Lecture 2 Flashcards
Describe the features of the adaptive immune system.
(specificity, diversity, specialization, clonal expansion, memory, contraction, non-reactivity to self)
Specificity
ensures that distnict antigens elecit specific respones
diversity
enables immune system to respond to a large variety of antigens
memory
leads to enhanced response to repeated exposures to the same antigens
clonal expansion
increases the number on antigen specific lymphocytes to keep pace with microbes
specialization
generates responses that are optimal for defense against different types of microbes
contraction and homeostasis
allows immune system to respond to newly encountered antigens
non-reactivity to self
prevents injury to the host during responses to foreign antigens .
this is importnat because you do NOT want to develop an autoimmune disease
non-reactivity to self
prevents injury to the host during responses to foreign antigens .
this is important because you do NOT want to develop an autoimmune disease
How is the adaptive immune response diverse?
The number of antigens that the immune system can recognize is
virtually limitless, estimated between 107 and 109.
Diversity! There are about 2x10^12 lymphocytes in the human body, most of which express a unique antigen receptor capable of recognizing a different microbial antigen.
clonal expansion
Daughter cells bare antigen receptor identical to that expressed by the parent cell.
will all be able to recognize the pathogen
clonal selection hypothesis
- Lymphocyte clones specific for different antigens develop before encounter with these antigens.
- Antigen recognition triggers the expansion of lymphocytes of a specific clone.
- Thereby specifically increasing the number of cells capable of recognizing/fighting the current infection.
contraction
Once the infection is cleared, the adaptive response declines (contracts), however, long lived memory cells remain.
primary vs secondary response to antigen…
explain the picture
unique feature of the adaptive immune response
At 15 months of age, a child received a measles-mumps-rubella (MMR) vaccine. At age 22, she is living with a family in Mexico that has not been vaccinated and she is exposed to measles. Despite the exposure, she does not become infected. Which of the following properties of the adaptive immune system is illustrated in this scenario?
memory
