If a researcher introduces a modified MHC class I molecule that cannot bind beta-2 microglobulin into a human cell culture, which consequence follows regarding the adaptive immune response?

💡 Explanation

Cytotoxic T-cells (CTLs) require MHC class I molecules to present intracellular antigens. The association with beta-2 microglobulin is crucial for MHC class I stability and surface expression; because the modified MHC cannot bind it, surface expression is severely reduced, and CTL activation is impaired. Therefore, the correct answer is C, rather than A, B, or D, because MHC class I presentation is necessary for T-cell activation, not antibody or complement responses.

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