HLA class I and II antigens

HLA matching

The human leukocyte antigens (HLA) have been defined by serological methods. There exist two kinds of receptor classes for major histocompatibility complexes (MHC): MHC class I and MHC class II. The class I antigens are HLA-A, HLA-B, and HLA-C and the class II are HLA-DR-, HLA-DQ, and HLA-DP. By determining HLA type an assessment of histocompatbility is made.

It is thought that HLA-A, HLA-B and HLA-DR are the most relevant for graft outcome. CD4 Th1 and CD8 T cells recognize the graft’s MHC class I and II. Most transplants are performed across some HLA class I and/or II difference, and thus generate T-cell mediated allo-reactions. This is called acute rejection, it takes days to develop and can be prevented.


Which one of the following interactions between surface molecules must take place for a T-cytotoxic cell to be stimulated to begin to destroy a virus-infected cell? (assume that the antigen and the receptor are also interacting correctly)