One Striking Feature of TCR Interactions with Peptide:MHC Complexes Is

question 17

Multiple Choice

One striking feature of TCR interactions with peptide:MHC complexes is that amino acid residues in the MHC protein are as important to the TCR binding strength as are amino acid residues in the pathogen-derived peptide. This feature is in contrast to antigen recognition by antibodies, which is a direct interaction that is independent of other host proteins. Based on the different functions of T cells versus antibodies in the adaptive immune response, the fact that TCRs recognize components of both the MHC and the bound peptide exists to:

• A) Prevent TCRs from binding only to surface exposed epitopes of native pathogens
• B) Prevent immune evasion by a pathogen that has mutated the sequences required for antibody recognition
• C) Put constraints on T cell recognition, due to the potentially damaging effector molecules made by activated T cells
• D) Ensure that TCRs are focused on recognizing antigens associated with host cells, and not those that are free in solution
• E) Ensure that the pathogen has already been destroyed by the host cell before the T cell will recognize it

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A data field specifically used for storing the state portion of an address or geographical information in databases and applications.

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