?:definition
|
-
Combining with an MHC class II protein complex and transmitting the signal from one side of the membrane to the other to initiate a change in cell activity. [GOC:add, GOC:signaling, ISBN:0781735149]
-
OBSOLETE. A major histocompatibility complex class II receptor. These display processed antigens from virally-infected or transformed cells. Class-II-positive cells (\'antigen-presenting cells\') can take up antigens from outside by endocytosis, degrade them into small peptides, and re-export the peptides (now bound to MHC class II protein) to the cell surface. These peptide-MHC class II complexes can then be recognized by specific CD4+ lymphocytes. [ISBN:081533642X, ISBN:0879694971]
|