Cell-surface molecules in the regulation of immune responsiveness

This paper reviews current knowledge genetics, structure and function on three categories of cell-surface molecules that affect immune responsiveness. It is focused on human molecules, but some references to murine analogues are made. First, the Major Histocompatibility Complex (MHC) molecules are discussed from the point of view of the associative recognition of antigenic peptides. The multiplicity, polymorphism and heterozygosity of MHC genes is correlated with the fine structure and the function of the molecules encoded by these genes. Second, selected CD molecules that are involved in cell-cell interaction and transduction of signals are discussed and correlated with discrete subsets of T cells, finally, some cell-surface receptors, antigen-specific and interleukin-specific, are analyzes, the effect of various molecules on immune responsiveness is illustrated by the actual experimental data. A minimal or parsimonious of triggering an immune response in which the discussed molecules are involved is described as a starting point for further discussion.