The document discusses the immune response and antibodies. It defines antigens and antibodies, and describes the properties of antigens. There are two types of immunity: innate and acquired. Acquired immunity involves both humoral immunity through antibodies produced by B cells, and cell-mediated immunity through T cells. Antibodies are produced in response to antigens and have a specific structure. The stages of the humoral immune response include the primary and secondary responses, which differ in speed and antibody levels produced. Factors like age, genetics, nutrition, and antigen dose can affect antibody production.

1. 18 October 2020 1VIGNAN PHARMACY COLLEGE, VADLAMUDI
Dr. Pulipati Sowjanya
Professor & Head
Dept. of Pharmaceutical Biotechnology
Vignan Pharmacy College
Vadlamudi, Guntur (Dt)

2. • The specific reactivity induced in a host by an antigenic
stimulus is known as the immune response.
• The immune response has a much wider scope and includes
reactions against any antigen, living or nonliving.
• It may lead to consequences that are beneficial, indifferent or
injurious to the host.
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3. The Immune Response
• Innate (nonspecific) Defenses against any pathogen
• Acquired immunity Developed during an
individual's lifetime
• Humoral immunity Involves antibodies produced
by B cells
• Cell-mediated immunity Involves T cells
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4. Specific Defenses of the Host:
The Immune Response
• Antigen (Ag) A substances that causes the body to produce
specific antibodies or sensitized T cells
• Antibody (Ab) Proteins made in response to an antigen
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5. Properties of Antigens
Antigens cause an immune response, also called immunogens
Protein or complex
carbohydrates
Antigens are larger than
10,000 Daltons
Epitopes are regions
recognized by antibodies
or T cell receptors
This protein would have
several epitopes
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6. Antigenic Determinants
Antibodies recognize and react with antigenic determinants or epitopes.
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8. Antibody Structure
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9. B cells and Antibodies
B cells produce antibodies
Antibodies are complex proteins
Variable region is highly specific
for antigen
There are 5 classes of heavy chains
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10. CLASSES OF IMMUNOGLOBULINS

11. Different Immunoglobulins
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12. Stages of Humoral Immune Response
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13. PRIMARY IMMUNE RESPONSE
• The antibody response to an initial antigenic stimulus differs
qualitatively and quantitatively from the response to subsequent
stimuli with the same antigen.
• The former is called the primary response and the latter the
secondary response.
• The primary response is slow, sluggish and short-lived, with a
long lag phase and low titre of antibodies that does not persist
for long.
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14. SECONDARY RESPONSE
• The secondary response is prompt, powerful and prolonged,
with a short or negligible lag phase and much higher level of
antibodies that lasts for long periods.
• The antibody formed in the primary response is
predominantly IgM and in the secondary response IgG.
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Primary Vs Secondary Immune Response

16. FACTORS AFFECTING ANTIBODY PRODUCTION
1. AGE: The immune response shows rapid improvement after
birth and this response continues to improve at least upto the age
of one year.
2. GENETIC FACTOR: Immune response is under the control of
genes. Response in different individuals to same antigen varies
due to genetic factor.
Persons capable of responding to a particular antigen are called
responder & those who cannot respond are termed non responder.
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17. 3. NUTRITIONAL STATUS:-
Immune response is suppressed in protein, calorie, mal
nutrition and in deficiency of some essential Amino acids and
vitamins.
4 . DOSE OFANTIGEN:-
An Antigen is immunogenic only when adminstered above a
minimal critical dose.
Small dose does not stimulate antibody production and large
dose may inhibit antibody production.
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18. References
1. RamReddy, Textbook of Microbiology, Volume-III (Pg. 9-25 )
2. S.B. Sullia & S.Santharam, General Microbiology, (Pg. 415,418 )
3. Guyton and Hall, Textbook of Medical Physiology, (Pg. 444 )
4. Harshmohan, Textbook of Pathology, ( Pg. 68 )
5. S.P.Vyas and V.K.Dixith, Pharmaceutical Biotechnology, ( Pg.
456)
6. Ananthanarayan & Paniker’s, Text book of Microbiology 7th
Edition (Pg.117-129)
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