We learned in Chapter 5 that the benefit of having and expressing multiple MHC class I and class II genes is that it increases the number and variety of pathogen-derived peptide antigens that can potentially be presented to T cells
If more is better, then why has natural selection not favored the evolution of more than three genes each for MHC class I and MHC class II?
What will be an ideal response?
Beyond a certain number of isotypes, the T-cell repertoire will be decreased, owing to the disproportionate increase in negative selection events as the number of different isotypes increases. Each additional isotype will decrease the number of T cells exported to the periphery, compromising the diversity of the T-cell population.
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Indicate whether the statement is true or false
T cells and B cells are the main types of
A. cytokines. B. lymphocytes. C. leukocytes. D. macrophages.
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Answer the following statement true (T) or false (F)