Classical MHC Molecules Function as Peptide-Binding Receptors That Present These $\alpha$

question 1

Multiple Choice

Classical MHC molecules function as peptide-binding receptors that present these peptides to $\alpha$ : $\beta$ T cells for recognition by $\alpha$ : $\beta$ T-cell receptors. MHC molecules can be detected as far back in evolution as sharks, the same time at which T-cell receptors can be identified. Examination of shark MHC proteins indicates that these molecules likely function identically to human MHC molecules. This conclusion is based on:

• A) The conservation of amino acid residues important in peptide binding in both shark and human MHC proteins
• B) The observation that MHC genes are highly polymorphic in sharks as well as humans
• C) The fact that sharks have both MHC class I and MHC class II molecules
• D) The finding that sharks have both classical and nonclassical MHC molecules, like humans
• E) The ability to trace the evolution of MHC protein sequences from the earliest vertebrates to humans

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Psychological Disorders

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