the specific immune response

characteristics of the specific immune response
1. specificity
IR is specific for specific Ag or specific component of Ag; epitopes/determinants = portion of Ag recognized by lymphocytes

2. memory
IS remembers Ag; therefore the second response = quicker, more intense

3. self regulation
feedback regulation of IR; normal IR wanes/decreases after time, return to dormant state

4. diversity
lymphocytes can respond to a very large number of Ag

5. distinguish self from non self i.e. recognizes foreign
IS can distinguish between foreign and self Ag (define self Ag)


The specific immune response has 2 components
1. primary IR
2. secondary IR


primary response
This can be illustrated in a graph showing the different stages as described below

specific Ab appear in blood after 3 – 14 days
latent period (lag phase) involves Ag recognition and development of lymphocyte clones
log phase shows a rise in [Ab] logarithmically until it reaches a peak
IgM is the principal Ab synthesized.
decline phase depicts a drop of [Ab] to very low levels

primary response vs secondary response
(Features of secondary IR that are different to primary IR)

1. more rapid than primary response
2. shorter latent period
3. decreased amount of Ag needed to invoke response
4. more Ab produced
5. decline phase is slower
6. predominant Ab is IgG
7. affinity of Ab increases

remember the above differences as we will be doing an in class exercise using this information.

questions for all students (mainstream and extended group)

Classify the following as either specific, non specific, primary, secondary, non immunogenic:

IV injection of penicillin; Anti diarrhoeal tablets; Inflammation; Sore throat
Fever; Sinusitis; Hay fever; WBC; neutrophils; urine; tears; lysozyme; tea; allergy; no symptoms on exposure to German measles; HIV; AIDS; food; lactose in lactose intolerant people;