Question XV. The genes encoding MHC class I and class II molecules are highly po

Question

Question XV. The genes encoding MHC class I and class II molecules are highly polymorphic in human populations. Specific MHC allotypes have been associated with increased susceptibility or resistance to certain viral infections. This influence of MHC molecules on disease susceptibility can be best explained by the fact that [complete the sentence and assess each subsequent statement (135-138) as either factually correct (= “true”) or incorrect (= “false”)]:

This question has confused me. The use of the word "best" seems to imply there is one answer that is true and all others are false. Please answer this question in the context that 1. you could only pick ONE answer as the BEST, which one you would pick and 2. if you could answer more than one as true/best which ones would be true

135. viral infection of DCs results in the presentation of viral peptides by MHC molecules, which stimulates the activation of naive T lymphocytes.
136. T cells become restricted to either MHC class I or MHC class II allotypes during their thymic development and this determines whether they become polarized towards TH1 or TH2 responses, respectively.
137. different MHC allotypes differ in their ability to distinguish harmful compounds from harmless self antigens.
138. different MHC allotypes bind different peptides and, therefore, some allotypes can present peptides from certain viruses better than peptides from other viruses.

Explanation / Answer

135. False. Viral infection can occur in any somatic cell. MHC-I are expressed by all somatic/nucleated cells and stimulate T cells

136. False. T cell subtypes are not concerned with differential abilities of individuals to respond to different antigens.

137. False. MHC cannot differentiate between hamrful and harmless antigens.

138. True. The ability of a person to react against an antigen depends on whether the antigenic peptides are presented to the T cells in context with MHC or not. Different alleles of MHC genes encode different peptides. These peptides vary in the ability and strength to bind the antigens. If an MHC peptide cannot bind an antigen, immune response cannot be elicited against that antigen.

Related Questions

Navigate

• Browse (All)
• Browse Q
• Subjects

Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.