Empowerment Summit for Graduating Students

FEDERAL UNIVERSITY OF TECHNOLOGY AKURE
ALUMNI ASSOCIATION
Empowerment Summit for Graduating Students
Module 2
-Finding & Securing Your Dream Job –
orEmpowerment Skills for Family Workers: A Worker Handbook,The Comprehensive Curriculum of the Cornell Family Development Credential
-Starting Your Dream Vocation/Business-
© Oseghe A.I. 2009








Empowerment Summit for Graduating Students
Outline
Finding & Securing Your Dream Job
• Job Prospecting Researching Your CV & Writing Cover Letters
• Preparing for pre-Employment Tests
• Attending Job Interviews
• Post Interview Follow-Up
Starting Your Dream Vocation/Business
• Assessing Self as an Entrepreneur
• Researching & Developing the Business Idea
• Critical Competencies &How to Acquire them
• The Need for Apprenticeship
Finding & Securing your Dream Job
Introduction.
Career prospecting is the process of looking for and securing the jobs of our dream.
Prospecting for a job:
1. Newspapers & Magazines
2. Parents, Parents Friends, Friends & Colleagues,
3. Family Relations ( uncles, Anties, Cousins e.t.c )
4. ReferralsEmpowerment Skills for Family Workers
5. Senior Colleagues & Mentors
6. Listening to conversations.
7. Professional Associations
8. Internet.
9. Recruitment Agencies
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2. Writing Curriculum Vitae & Cover Letters
SAMPLE CURRICULUM VITAE
12 Bajulaye,
xxxxxxxxxxxx
Cell Phone:
Agege-Ogba
Office:
Xxxxx xxxx ext xxx
Home:
XXXXXXXX
Ikeja, Lagos.
e-mail:
xxxx@hotmail.com
Anthony O. John
BSC (HONS),.
Can assist your Company to :
Mention the things you can do for the organisation :
•
Personal Data Date of Birth
: 12
July, 1920.
t h
Sex / Marital Status
: Male / Married with 20 Children.
State of origin
: Abia State. ( Optional)
Educational
Federal University of Technology, Akure
,
Nigeria
1945
–
1947
Qualifications
MBA ( General Management )
Final Result - 10 Distinctions, 9 Upper Credits, 1 Credit. (CGP 4.42 out of Max. of. 5)
DPMS/IBM Computer Institute, Lagos, Nigeria
1994 - 1995
Diploma in Computer Studies
Final Result - Distinction.
Lagos State University
,
Lagos, Nigeria
1984 - 1989
Bachelor of Science in Business Administration
Final Result - 2
Class Lower division (3
best graduating student in the department )
nd
r d
St Gregory College, Lagos, Nigeria
1983 - 1984
G . C .E '0' Level
Final Result - 4 Distinctions, 2 Credits.
Xxxxx Company Nig Plc.
Lagos
Working
Sept. 2003 – Jun. 2004
Experience
Logistics Officer (NYSC)
• Finished Products Output planning
• Preparation of Production Forecasts and Plans weekly, monthly, Quarterly &
Yearly.
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Specific Achievements in job function
• Assisted to save the company =N=000,000 from invoices that were represented
Specific Commendation or awards specific to job function.
• Employee of the month for August 2008
Relevant
Date COURSE ORGANISER
Training
Programs
24-25 Jul. 2003 Self Management Programme NCCF Lagos Branch
Professional
• Associate member, Nig erian Institute of Managemen t –1986.
Memberships
•
Evaluation of the impact of TQM implementation on productivity and corporate performance at NNPC
Relevant
(MBA Thesis.) June 1999.
Research
•
Assignments
The manufacturing sector of Nig. economy (The past, present, & future) Feb. 1999.
•
Small Business failures in Nigeria. (Causes, Consequences, & Success Factors) June 1998.
•
Effect of leadership style on motivation and performance of subordinates in a corporate setting.
Case of Xxxxxxx. (PG DIP Thesis.) Aug. 1997.
2001 XXXXXXXXX
Award recipient
for year 200x
Awards
Received
Oct 1990
XXXXXXXX Award recipient
for outstanding
- . performance during 198x/9x NYSC service year.
1985-89 Xxxxxxxxxx Undergraduate Scholarship award.
July 1983 College award for being the
Senior Prefect 198X/8X
session.
Languages
Eng lish, Yoruba, Xxxxxxxxx
Teaching, Coaching, Meeting people, Graphic arts, Music.
Hobbies
References
Name,
Address,
Telephone Number & E-mail Address
Usually of 3 (1 Current Employer, 1 Past Lecturer, and 1 Senior colleague or mentor)
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SAMPLE APPLICATION COVER LETTER
15 BAJULAIYE STREET LAGOS.
Office Phone
: XXXXXXXX EXT. XXX, GSM: 0 8 0 3 3 0 5 0 7 7 5,
E-mail
: xxxxxx@hotmail.com
September 30, 2008
The Head of Human Resources (or as advertised)
22 Xxxxxxxx X xxxxxxxxxxx,
Lagos, Nigeria.
Dear Sir,
For unsolicited applications :
APPLICATION FOR EMPLOYMENT
I wish to be considered for a suitable position or (state the position you are interested in) in your organization. My brief profile is as summarized below: Go straight to Age as
shown below.
If you are responding to an advert , please refer to the advert :
RE: VACANCY ( Title of Job as Advertised) (REF. SNE1)
I wish to be considered for the above vacancy as advertised in the Guardian Newspaper of 15 July, 2004.
In relation to your requirements as specified, my profile is as summarized below:
AGE
: XX years
QUALIFICATIONS:
Start with the most recent Certificate or the one that relates most to the job you are applying for and let them know some of the other development
and training programmes you have attended. e.g
Bachelors degree in Chemical Engineering. I have attended many professional and personality development programs and retreats on xxxxxxxxx.
Academic awards can also be slotted in here.
MEMBERSHIP OF PROFESSIONAL ASSOCIATIONS:
Nigerian Institute of Management (
NIM
) , Institute of Management Consultants of Nigeria (
IMC
) , and the xxxxxxxxxxxx
EXPERIENCE:
I have a total of
xx years
of working experience covering (
what has been advertised or related to what has been advertised
). I was part of
The team that ( …..Achievements related to what you’ve applied for) . At the moment I work for XXXXXXXl Ltd where I have responsibility for XXXXXxxxxxxxxx. OR During
my Youth Service in 2004 I worked for Xxxxxxxxxxxx LTD as Xxxxxxxxxxxxxxxxxxxx where I was involved in xxxxxxxxxxxxxxxxxxxxxxxxxx.
SPECIAL SKILLS & ATTRIBUTES:
• .XXXXXXXXXXXX ( Usually from the advert if you are familiar with it)
• XXxxxxxxxxxxxxxxx
Please find attached my CV which details my capabilities. I believe you will find my service useful to your organization, and would appreciate the opportunity of an interview.
Yours Sincerely,
Anthony O. John
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Grace Agbakoba
Block 88, Flat 7 Obanla Medium Estate beside Futa Gate, Akure.
Cell Phone- 08033050887 E-mail- graceagbakoba@yahoo.com
16-May-2007
The Managing Director
Peoples Bank Plc
Marina, Lagos
Dear Sir,
APPLICATION FOR JOB AS INFORMATION TECHNOLOGY(IT) PROFESSIONAL AT PEOPLES BANK PLC
I wish to be considered for the above position. My Profile is as summarised below.
Age
23years
Qualification
A Bachelors degree in Computer Science in addition to a Post-Graduate Diploma in Business
Administration. I am a certified Oracle Database Management (9i) Professional and have passed
the Foundation Stage examination of the Association of Certified Chartered Accountant (ACCA). I
have also attended many professional and personality development programs and retreats on
Information/Communication Technology (ICT) and Business Management.
Membership of Professional Associations.
Student, member of ACCA, Member, Oracle Professionals Association, Member, Computer
Association of Nigeria.
Experience
Total of 14years work experience covering System Administration in the Banking industry,
independent ICT consulting and IT business solution services in Accounting, Human Resources
Management, Inventory Management/Point of Sale Systems
Special Skills & Attributes
• Business application development, customization, implementation and support.
• Proficient in the use of Microsoft Office Tools
• Formulation of policies and procedures on Information Technology Management
• Consulting, Project Management, Communications and Presentation.
Please refer to the attached CV for details on my experience, achievements and the various projects handled to date.
I believe you will find my experience and exposure useful to your organization, and would appreciate meeting with you at
your earliest convenience.
Yours Sincerely,
Grace Agbakoba
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3. Attending Interviews.
Employee of Choice:
What the Interviewer would like to see.
• Appearance
• Interest
• Knowledge, experience, skills, and abilities to perform the job
• Expectation about job duties
• Attitude
• Time Availability
• Reasonable Expectation
• Intelligence
• Adjustment
• High Motivation and Achievement
Preparation for the Interview
• Arrive 5 minute early
• Know the exact about the place and time of the interview, the name of the interviewer
• Know what interview is all about
• Get the information about the company, even the small thing
• Take a deep breath that make you keep calm
• Know how to answer common question
• Showing that you are really interest with the opening job
• Don't forget to brush your teeth before you go to the interview
• Select the appropriate clothing, accessories and perfume
• Boldness
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5. Answering Interview Questions
15 Common General Interview Questions & How to answer them.
Tell me about yourself.
* Keep your answer to one or two minutes; don't ramble. * Use a ''positioning statement''
as a base to start. Your positioning statement is the boiled-down story of your resume -- general goals, skills and
background.
What do you know about our company?
* Know products, size, income, reputation, image, goals, problems,
management talent, management style, people, skills, history and philosophy. * Project an informed interest. Ask
several open-ended questions about the company's course and the department's goals so the interviewer can tell
you about the company. Let her define the business in her terms.
Why do you want to work for us?
* Don't talk about what you want; first talk about their needs.
* You wish to be part of a company project. * You would like to solve a company problem. * You can make a
definite contribution to specific company goals: identify its management talent, increase sales in the Northeast
region, and so on.
What would you do for us? What can you do for us that someone else can't?
* Relate past successes in solving previous employer problems, which may be similar to those of the prospective
employer.
What about our position do you find the most attractive? Least attractive?
* List three or more attractive
factors and only one minor unattractive factor.
Why are you leaving your present job?
* Refine your answer based on your comfort level and honesty. * Give a
"group" answer if possible; for instance, "Our department was consolidated or eliminated."
How do you feel about leaving all of your benefits?
* Concerned but not panicked.
Describe what you feel to be an ideal working environment.
* Where people are treated as fairly as possible.
How would you evaluate your present firm?
* An excellent company that afforded me many fine experiences.
Why should we hire you?
* Because of knowledge, experience, abilities and skills. Tell what these are.
What do you looking for in a job?
* An opportunity to use skills, perform and be recognized.
Please give me your definition of a ... (the job for which you are being interviewed).
* Keep it brief and action- and results-oriented
How long would it take you to make a meaningful contribution to our firm?
* Very quickly after a little orientation and a brief period of adjustment on the learning curve.
How long would you stay with us? *
As long as we both feel I'm contributing, achieving, growing and so on.
What important trends do you see in our industry?
* Keep your answer to two or three trends.
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8 Questions on Your Work Habits and Style:
If I spoke with your previous boss, what would he say are your greatest strengths and weaknesses? * Emphasize
skills -- don't be overly negative about your weaknesses; it's always safe to identify a lack of a skill or experience
as a shortcoming rather than a personal characteristic.
Can you work under pressures and deadlines? * Yes. Quite simply, it is a way of life in business.
How have you changed the nature of your job? * Improved it, of course.
Do you prefer staff or line work? Why? * It depends on the job and its challenges.
In your present position, what problems have you identified that had previously been overlooked? * Keep it brief
and don't brag -- that is, stick to the facts.
Don't you feel you might be better off in a different size company? Different type company? * Depends on the job -
- elaborate slightly.
How do you resolve conflict on a project team? * First discuss issues privately.
What was the most difficult decision you ever had to make? * Attempt to relate your response to the prospective
employment situation
Salary Questions:
How much are you looking for? * Answer with a question: ''What is the salary range for similar jobs in your
company?'' * If they don't answer, then give a range of what you understand you are worth in the marketplace.
How much do you expect, if we offer this position to you? * Be careful; the market value of the job may be the key
answer -- ''My understanding is that a job like the one you're describing may be in the range of $______.''
What kind of salary are you worth? * Have a specific figure in mind, but don't necessarily volunteer it. . Show your
willingness to reach a mutually agreeable solution
Personality Questions:
What was the last book you read? Movie you saw? Sporting event you attended? * Talk about books, sports or
films to represent balance in you life.
How would you describe your own personality? * Balanced.
What are your strong points? * Present at least three and relate them to the interviewing company and job
opening.
What are your weak points? * Don't say you have none. * Try not to cite personal characteristics as weaknesses,
but be ready to have one if interviewer presses. * Turn a negative into a positive answer: "I am sometimes intent
on completing an assignment and get too deeply involved when we are late."
Comportment at Interviews.
• Don't panic, but be natural and relaxed
• Maintain the eye contact
• Be self-assured and honest, so you can avoid being worried about inconsistency in your answers
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• Keep away from the things negative about yourself, others or past employers
• Don't answer anything when you don't have the question
• Keep enthusiasm in your voice
• Don't show that you loose your hope when you can not answer the question
• Asked for the good reason and answer appropriately
• Avoid showing non-verbal communication signals when you get bored or not interest
• Take some time before you answer the question
• Be focused on the question
• Don't blame the previous company
Common Mistakes at the Interview
1. Not listening that make the interviewer asked you again with the same question
2. Showing you are not prepared about the interview, just sit down and keep silent
3. Talking too much especially about the irrelevant topic
4. You are not sure what you want to do
5. Showing the body signals that you are disinterest
6. Chew the gum and smoking
7. Use the slang language
8. Blame your previous company
9. Only focus the salary and benefits, when the interviewer not initiated to ask you
10. Being hesitate to work for long hours
Summaries & Conclusions
• Research jobs and opportunities
• Prepare a good CV and Covering letter.
• Follow up with your application
• Prepare well for the interview
• Put your self at ease during the interview
• Only ask work related questions.
• Thank the panel after the interview.
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Starting Your Dream Vocation/Business
Nine Steps to Starting Your Business:
1 Assess your self as an entrepreneur.
2 Develop a business idea
3 Assess your market and develop a marketing plan
4 Organise your business
5 Cost your product or Services
6 Estimate your start up capital
7 Make financial plans
8 Choose a legal form for your Business
9 Make an action plan to actualise your business.
1. Assessing Self as an Entrepreneur:
Skills & How to Acquire them
Technical Skills
:
Practical abilities you need to provide the product or provide the services. This will depend on the type of
business.
Business Management Skills:
Abilities required to run the business e.g Selling skills, Costing and Record-keeping skills .
•
Knowledge of your specific line of business :
Nature of the raw material
Handling and storage
What type of the product people need
The process of making each item
What staff, tools and equipment are needed,
How the product is marketed.
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Many business owners do not have all the skills before they began:
Learn the skill, and develop all the characteristics by talking to people, observe other business people,
attend formal training, Read books on the abilities and subject you need to learn more about.
Financial Situation
If your proposed business will require a lot of capital, then you’ll need lots of personal money to start it.
You can not put in all your money into business.
The amount of money to invest in your business must be assessed.
A. Assess what is available now + what will come in the next 5 months.
B. Assess what you need to spend in the next 5 months on personal maintenance.
Investable funds = B – A.
2. Researching & Developing the Business Idea
A successful business starts from a good business idea. Before you can plan your business, you need a
detailed description of what your business will do and how it will operate. This is the starting point. By doing
this you will easily know if there are weaknesses in your business idea.
Types of Business you can start:
A Retail Business: Buys goods from Manufactures or retailers and sells directly to customers.
•
A Wholesale Business: Buying from Manufacturers and selling to retailers.
•
A Manufacturing Business: Making thingsSearch Amazon.com for empowerment skills for family workersEmpowerment Skills for Family Workers: A Worker Handbook,The Comprehensive Curriculum of the Cornell Family Development Credential
•
A Service Business: Provision of advice or labour.
•
A Combination of any of the above.
•
Documenting your Business Ideas
What products or service your business will sell?.
•
Is it many different products or service or only one?.
•
Is your product something completely new?
•
Do you have the technical skills to provide it?
•
Would you need to employ people to make these products or services or outsource it?.
•
Who is going to buy your product or service?.
•
Private people or other businesses?
•
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Are they within a small area or are spread over a large area?
•
Why your customers are going to buy your products or services?
•
What needs does the customer need to satisfy?
•
How your business is going to sell its products or services?.
•
Sell directly to customers or retailers?
Home sales?
Internet? e-commerce.
Delivering a service to customers in their homes?
Document your business idea in a written Business Plan.
Executive Summary
Business Idea
Marketing plan
Business Organisation
Costing
Start-up Capital
Financing and Profit
Legal form of the Business.
3. Assess your market and develop a marketing plan
. You need customers to succeed in Business.
. All the people who might want to buy your products or services is your market.
. Your business must attract people who might want to buy from you.
. To start your business, you need to understand the characteristics of your customers, your
competitors, and the size of the market.
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4. Organise your business
A business must be organised to run smoothly, efficiently, and successfully. Organising is all about knowing
what needs to be done, how and where it is to be done, and having the people and resources to do the work.
Ascertain:
. What staff your business needs and what jobs they should perform and how you will manage them.
. How much space your business needs for shop, workshop, storeroom, office and public facilities.
. What machines and equipment are necessary?
. Estimate the rew material input that will be required.
5. Cost your product or Services
a. Costing helps you to :
Set prices
•
Reduce and control costs
•
Make better decisions about what to do in your business.
•
Plan for the future.
•
b. As a business owner you need to know in details the cost of running your business as you cannot set
your prices without it.
c. Lack of ability to do costing properly has resulted in the failure of many businesses.
d. You need to know whether the sale coming from your businesses will cover the cost of running it.
6. Estimate your start up capital
a. Pre- Operating expenses
. Payment for land & building , furniture, machinery and equipment, legal fees, connection charges,
advertisement before opening.
. Start you business in a rented apartment or from home.
b. Initial Operating payments (Working Capital).
. Money you will pay out during the first 3-6 months of operation. e.g Rent, Purchase of stock,
insurance, utilities, telephone, office supplies, promotion and advertising, owners salary, staff wages.
. You must have enough to cover these payments until you can pay them from your sales revenue.
. Amount depends on the nature of the business.
Sources of Startup Capital
Equity funds : Owners money
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Borrowing: Friends, financial institutions and Cooperatives, Special loans and grants from government.
When borrowing, beware of :
The loan period,
Payback condition,
Grace period,
Interest rate.
Rent or lease resources.
You will need to make a finance scheme to cover your payback conditions and interest payments.
It is tough raising money for start-up businesses. You may wish to consider combining funds from
various sources.
Plan to start small and expand the business over time.
7. Make financial plans
. Estimate what your costs and sales are likely to be during the 1st year of business.
. Find out when the business is expected to make profit during the year.
. Identify the financial problems the business may have during the first year and work out what you
need to do to solve them before they happen.
. Present a clear picture of your cash flow.
Sales & Cost Plan
Sales of each month (-) Staff and operations cost - Depreciation
(-)Interest(=) Gross profit (-) Income tax (=) Net profit. Note: Income tax and Net profit are only calculated
at the end of the year. The sales and cost plan is what investors and lending institutions will look at carefully.
8. Choose a legal form for your Business
Types of Legal forms of Business:
. Sole Proprietorship
. Partnership
. Limited Liability
. Public Liability Company.
.
You need to choose the most convenient legal form for your business.
9. Make an action plan to actualise your business.
Complete your Business Plan. A good one should contain:
. Executive Summary
. Business Idea
. Marketing plan
. Business Organisation
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. Costing
. Start-up Capital
. Financing and Profit
. Legal Form of the Business
Critical Success Factors for the Entrepreneur
Success in business is a function of the entrepreneur’s:
1. Personal Characteristics and situation,
Strong commitment to the business.
Strong motivation to own a business
Be able to taking well considered risks
Be able to make important decisions
Have support of family & friends
2. Skills. ( Technical, Business Management Skills, Knowledge of your specific line of business,
3. Financial situation.
Should You Start a Business?
Ask your self the following questions:
Do you have the time and commitment to manage your new business?
Will your business have customers?
Can you supply what your customers want?
Will your customers pay enough to cover your business costs?
Can you raise enough money you need to start the business?
Will the profit be high enough to pay you an acceptable salary?
If your answer to all the above is 100% , then you can go ahead with the business plans implementation.
If not, you may need time to think everything thoroughly.
To Actualise Your Business Plan
Find a suitable business location
Find the start-up capital
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Register the business
Have the utilities connected
Buy or rent, or lease equipment and machinery
Buy stock
Employ staff if need be
Take out insurance
Promote and advertise the business
Meet every special requirements you may have
.
References
1. Various materials fro the internet
2. ILO publication of Start Your Business.
Innocent Oseghe
Cell Phone: 08033045547
Land line: 2798949
E-mail:
innocent.oseghe@ng.kpmg.com
or innocentoseghe@aol.com
‘‘Please note that information contained herein are of generic nature and are not intended to address the circumstances of any particular
individual or entity. No one should act on this information without appropriate guidance/advice and after a thorough examination of the
particular situation’’. Every individual is expected to prepare theirs based on their circumstance’’.
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Immune System

Immune System
I INTRODUCTION
Immune System, group of cells, molecules, and organs that act together to defend the body against foreign invaders that may cause disease, such as bacteria, viruses, and fungi. The health of the body is dependent on the immune system’s ability to recognize and then repel or destroy these invaders.
II IMMUNITY: INNATE AND ADAPTIVE
Most animals have systems that resist disease. The disease resistance provided by these systems is called immunity. There are two types of immunity: innate and adaptive. Innate, or nonspecific, immunity is the body’s first, generalized line of defense against all invaders. Innate immunity is furnished by barriers such as skin, tears, mucus, and saliva, as well as by the rapid inflammation of tissues that takes place shortly after injury or infection. These innate immune mechanisms hinder the entrance and spread of disease but can rarely prevent disease completely.
If an invader gets past this first line of defense, the cells, molecules, and organs of the immune system develop specifically tailored defenses against the invader. The immune system can call upon these defenses whenever this particular invader attacks again in the future. These specifically adapted defenses are known as adaptive, or specific, immunity.
Adaptive immunity has four distinguishing properties: First, it responds only after the invader is present. Second, it is specific, tailoring each response to act only on a specific type of invader. Third, it displays memory, responding better after the first exposure to an invader, even if the second exposure is years later. Fourth, it does not usually attack normal body components, only those substances it recognizes as nonself.
Adaptive immune responses are actually reactions of the immune system to structures on the surface of the invading organism called antigens. There are two types of adaptive immune responses: humoral and cell mediated. During humoral immune responses, proteins called antibodies, which can stick to and destroy antigens, appear in the blood and other body fluids. Humoral immune responses resist invaders that act outside of cells, such as bacteria and toxins (poisonous substances produced by living organisms). Humoral immune responses can also prevent viruses from entering cells.
During cell-mediated immune responses, cells that can destroy other cells become active. Their destructive activity is limited to cells that are either infected with, or producing, a specific antigen. Cell-mediated immune responses resist invaders that reproduce within the body cells, such as viruses. Cell-mediated responses may also destroy cells making mutated (changed) forms of normal molecules, as in some cancers.
III COMPONENTS OF THE IMMUNE SYSTEM
The ability of the immune system to mount a response to disease is dependent on many complex interactions between the components of the immune system and the antigens on the invading pathogens, or disease-causing agents.
A Macrophages

Macrophage Engulfing Bacterium
A macrophage, in yellow, engulfs and consumes a bacterium. Macrophages are large phagocytes, cells that wander through the body consuming foreign particles such as dust, asbestos particles, and bacteria. They help protect the body against infection.
Dennis Kunkel/CNRI/Phototake NYC
White blood cells are the mainstay of the immune system. Some white blood cells, known as macrophages, play a function in innate immunity by surrounding, ingesting, and destroying invading bacteria and other foreign organisms in a process called phagocytosis (literally, “cell eating”), which is part of the inflammatory reaction. Macrophages also play an important role in adaptive immunity in that they attach to invading antigens and deliver them to be destroyed by other components of the adaptive immune system.
B Lymphocytes

Lymphocyte
Scanning electron micrograph of a normal T lymphocyte. T lymphocytes are specialized white blood cells that identify and destroy invading organisms such as bacteria and viruses. Some T lymphocytes directly destroy invading organisms, whereas other T lymphocytes regulate the immune system by directing immune responses.
NIBSC/Science Source/Photo Researchers, Inc.
Lymphocytes are specialized white blood cells whose function is to identify and destroy invading antigens. All lymphocytes begin as “stem cells” in the bone marrow, the soft tissue that fills most bone cavities, but they mature in two different places. Some lymphocytes mature in the bone marrow and are called B lymphocytes. B lymphocytes, or B cells, make antibodies, which circulate through the blood and other body fluids, binding to antigens and helping to destroy them in humoral immune responses.
Other lymphocytes, called T lymphocytes, or T cells, mature in the thymus, a small glandular organ located behind the breastbone. Some T lymphocytes, called cytotoxic (cell-poisoning) or killer T lymphocytes, generate cell-mediated immune responses, directly destroying cells that have specific antigens on their surface that are recognized by the killer T cells. Helper T lymphocytes, a second kind of T lymphocyte, regulate the immune system by controlling the strength and quality of all immune responses.
Most contact between antigens and lymphocytes occurs in the lymphoid organs—the lymph nodes, spleen, and tonsils, as well as specialized areas of the intestine and lungs (see Lymphatic System). Mature lymphocytes constantly travel through the blood to the lymphoid organs and then back to the blood again. This recirculation ensures that the body is continuously monitored for invading substances.
C Antigen Receptors
One of the characteristics of adaptive immunity is that it is specific: Each response is tailored to a specific type of invading antigen. Each lymphocyte, as it matures, makes an antigen receptor—that is, a specific structure on its surface that can bind with a matching structure on the antigen like a lock and key. Although lymphocytes can make billions of different kinds of antigen receptors, each individual lymphocyte makes only one kind. When an antigen enters the body, it activates only the lymphocytes whose receptors match up with it.
D Antigen-Presenting Cells
When an antigen enters a body cell, certain transport molecules within the cell attach themselves to the antigen and transport it to the surface of the cell, where they “present” the antigen to T lymphocytes. These transport molecules are made by a group of genes called the major histocompatibility complex (MHC) and are therefore known as MHC molecules. Some MHC molecules, called class I MHC molecules, present antigens to killer T cells; other MHC molecules, called class II MHC molecules, present antigens to helper T cells.
IV HUMORAL IMMUNE RESPONSE
The humoral immune response involves a complex series of events after antigens enter the body. First, macrophages take up some of the antigen and attach it to class II MHC molecules, which then present the antigen to T helper cells. The T helper cells bind the presented antigen, which stimulates the T helper cells to divide and secrete stimulatory molecules called interleukins. The interleukins in turn activate any B lymphocytes that have also bound the antigen. The activated B cells then divide and secrete antibodies. Finally, the secreted antibodies bind the antigen and help destroy it.
A Antibodies
Antibodies are Y-shaped proteins called immunoglobulins (Ig) and are made only by B cells. The antibody binds to the antigen at the ends of the arms of the Y. The area at the base of the Y determines how the antibody will destroy the antigen. This area is used to categorize antibodies into five main classes: IgM, IgG, IgA, IgD, and IgE. During the humoral immune response, IgM is the first class of antibody made. After several days, other classes appear. Exactly which other Ig classes a B cell makes depends on the kind of interleukins it receives from the T helper cells.
Antibodies can sometimes stop an antigen’s disease-causing activities simply by neutralization—that is, by binding the antigen and preventing it from interfering with the cell’s normal activities. For example, the toxin made by tetanus bacteria binds to nerve cells and interferes with their control of muscles. Antibodies against tetanus toxin stick to the toxin and cover the part of it that binds to nerve cells, thereby preventing serious disease. All classes of antibodies can neutralize antigens.
Antibodies also help destroy antigens by preparing them for ingestion by macrophages in a process called opsonization. In opsonization, antibodies coat the surface of antigens. Since macrophages have receptors that stick to the base of the antibody’s Y structure, antigens coated with antibodies are more likely to stick to the macrophages and be ingested. Opsonization is especially important in helping the body resist bacterial diseases.
Finally, IgM and IgG antibodies can trigger the complement system, a group of proteins that cause cells to disintegrate by cutting holes in the cell membrane. Complement is important in resisting bacteria that are hard to destroy in other ways. For example, some of the bacteria that cause pneumonia have a slimy coating, making it hard for macrophages to ingest and eliminate them. However, if IgM and IgG antibodies bind to the pneumonia bacteria and activate the complement system, it is able to cut holes in the bacteria to destroy them.
Although the IgM and IgG classes of antibodies work best in the circulatory system, IgA can exit the bloodstream and appear in other body fluids. IgA is thus important in preventing infection at mucosal surfaces, such as the intestine and the lung. Since these are the sites where most infectious agents enter, IgA is particularly important in resistance to many diseases. IgA is also found in mother’s milk and may help nursing newborns resist disease.
V CELL-MEDIATED IMMUNE RESPONSE
As with the humoral immune response, the cell-mediated immune response involves a complex series of events after antigens enter the body. Helper T cells are required, so some of the antigen must be taken up by macrophages and presented to helper T cells. The helper T cells bind the presented antigen and thereby become activated to divide and secrete interleukins. The interleukins in turn activate any killer T cells that have already bound antigen attached to class I MHC molecules on infected cells. The activated killer T cells can then kill any cells displaying antigen attached to class I MHC molecules, effectively eliminating any cells infected with the antigen.
VI IMMUNIZATION

Immunization Schedule for Infants and Children
Physicians recommend that infants and children receive vaccinations to protect them from highly contagious diseases. Many vaccines require more than one dose to provide full immunity, and sometimes combination vaccines are used to lessen the number of injections a child receives. This chart provides the ages for immunization with specific vaccines that the American Academy of Pediatrics recommends for children living in the United States.
When the body is first exposed to an antigen, several days pass before the adaptive immune response becomes active. Immune activity then rises, levels off, and falls. During following exposures to the same antigen, the immune system responds much more quickly and reaches higher levels. Because the first, or primary, immune response is slow, it cannot prevent disease, although it may help in recovery. In contrast, subsequent, or secondary, immune responses usually can prevent disease because the pathogen is detected, attacked, and destroyed before symptoms appear. This complete resistance to disease is called immunity and may be achieved through either active or passive immunization.
A Active Immunization
Active immunization occurs when a person’s own immune system is activated and generates a primary immune response. Active immunization can be triggered in two ways, either by natural immunization or by vaccination.
In natural immunization, the body contracts a disease and recovers. Because a primary immune response occurs during the illness, the immune system will mount a disease-preventing secondary response every time it is subsequently exposed to the disease. Natural immunization is developed during childhood diseases, such as chicken pox. After having had the disease once, a person is no longer susceptible to it.
Vaccination is intentional immunization against a particular disease by the use of vaccines, substances that are structurally similar to the actual disease-producing agents but that do not produce disease themselves. Most vaccines take one of two forms. The first type of vaccine, such as the vaccines for tetanus and whooping cough, contains chemically killed bacteria or other pathogenic organisms. The other type, such as the oral polio vaccine, contains weakened forms of living organisms that have been genetically selected so they do not produce disease.
B Passive Immunization
Another way to provide immunity is by means of passive immunization. Passive immunization does not engage the person’s own immune system. Instead, the individual receives antibodies that were created in another person or animal. Such antibodies can be lifesaving when a disease progresses too rapidly for natural immunization to occur. For example, if a person who has not been immunized against tetanus bacteria is exposed to tetanus, the toxin produced by these bacteria would reach a deadly level before a primary immune response could begin. Administering antibodies against tetanus toxin quickly neutralizes the toxin and prevents death.
Passive immunization has two drawbacks: First, the person does not mount an active immune response, so the immunizing effect is temporary and the person is not immune after recovery. Second, if passive immunization is used repeatedly, it occasionally produces side effects.

VII IMMUNE SYSTEM DISORDERS
Disorders of the immune system can range from the less serious, such as mild allergy, to the life threatening, such as more serious allergy, transplant rejection, immune deficiencies, and autoimmune diseases.
A Allergy
Allergy, sometimes called hypersensitivity, is caused by immune responses to some antigens. Antigens that provoke an allergic response are known as allergens. The two major categories of allergic reaction, rapid and delayed, correspond to the two major types of immune responses.
Rapid allergic reactions, such as those to bee venom, pollen or pets, are caused by humoral immune mechanisms. These immediate hypersensitivity reactions result from the production of IgE antibodies when a person is first exposed to an allergen. The IgE antibodies become attached to mast cells—white blood cells containing histamine, the chemical that causes the familiar allergic symptoms of runny nose, watery eyes, and sneezing. Mast cells are particularly abundant in the lungs and intestine. If the antigen-binding sites of mast cells become filled with an allergen, the mast cells release histamine.
Allergic reactions that are slow in onset (known as delayed-type hypersensitivity, or DTH), such as those to poison ivy or poison oak, are cell mediated. Extreme examples of DTH occur when macrophages cannot easily destroy invading substances. As a result, T cells are activated, leading to inflammation of the body tissue. This inflammation continues for as long as the T cells are activated. The bacterium that causes tuberculosis also falls into this category because this bacterium is covered with a waxy coat that macrophages cannot destroy. The resulting DTH leads to the lung and liver damage associated with tuberculosis.
B Transplant Rejection
The immune system recognizes and attacks anything different from the substances normally present within an individual, even substances that are only slightly different, such as transplanted tissues and organs (see Transplantation, Medical).
When an organ is transplanted, the MHC of the donor organ is recognized as foreign and attacked by the recipient’s immune system. To minimize the chances of transplant rejection, physicians seek transplant donors who share as many MHC genes as possible with the transplant recipient. Even then, most transplant recipients are given drugs to suppress their immune response and prevent rejection of the transplant.
If the transplanted tissue contains T lymphocytes from the donor, as in bone marrow transplants, these donor T lymphocytes may recognize the recipient’s tissues as foreign and attack them. Physicians can reduce or prevent this potentially fatal graft-versus-host (GVH) reaction by removing all mature T lymphocytes from the organ or tissue before performing the transplant.
C Immune Deficiency
Deficiencies in immune function may be either inherited or acquired. Inherited immune deficiencies usually reflect the failure of a gene important to the generation or function of immune system components.
Some inherited diseases damage a person’s innate immunity by making macrophages incapable of ingesting or breaking down invading organisms. Individuals affected by these diseases are especially susceptible to opportunistic infections—that is, infections by normally harmless organisms that can flourish in a person whose immune system has been weakened.
DiGeorge syndrome is an inherited immune disorder in which a person has no thymus and, therefore, cannot produce mature T lymphocytes. People with this disorder can mount only limited humoral immune responses, and their cell-mediated immune responses are severely limited.
The most extreme example of a hereditary immune deficiency is severe combined immunodeficiency (SCID). Individuals with this disease completely lack both T and B lymphocytes and thus have no adaptive immune responses. People with SCID must live in a completely sterile environment, or else they will quickly die from infections.
Acquired immune deficiencies can be caused by infections and also other agents. For example, radiation therapy (see Radiology) and some kinds of drugs used in treating disease reduce lymphocyte production, resulting in damaged immune function. People undergoing such therapies must be carefully monitored for lowered immune function and susceptibility to infections. Environmental and lifestyle factors, such as poor nutrition or stress, can also affect the immune system’s general status.
An infectious agent resulting in fatal immune deficiency is the human immunodeficiency virus (HIV). This virus causes acquired immunodeficiency syndrome (AIDS) by infecting and eventually destroying helper T cells. Because helper T cells regulate all immune responses, their loss results in an inability to make adaptive immune responses. This complete lack of immune function makes individuals with AIDS highly susceptible to all infectious agents.


D Autoimmune Diseases
Autoimmunity is the immune response of the body turned against its own cells and tissues. Autoimmune diseases may involve either cell-mediated responses, humoral responses, or both. For example, in Type 1 diabetes, the body makes an immune response against its insulin-producing cells and destroys them, with the result that the body cannot use sugars. In myasthenia gravis, the immune system makes antibodies against the normal molecules that control neuromuscular activity, causing weakness and paralysis. In rheumatic fever, the immune system makes antibodies that bind to the heart’s valves, leading to permanent heart damage. In systemic lupus erythematosus, commonly known as lupus, the body makes antibodies against many different body tissues, resulting in widespread symptoms.
The mechanisms of autoimmune diseases are poorly understood, and thus the basis for autoimmunity is unclear. Much research focuses on trying to understand these mechanisms and should eventually result in cures.

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