D. Vidovic et al., DOWN-REGULATION OF CLASS-II MAJOR HISTOCOMPATIBILITY COMPLEX-MOLECULES ON ANTIGEN-PRESENTING CELLS AFTER INTERACTION WITH HELPER T-CELLS, European Journal of Immunology, 25(5), 1995, pp. 1326-1331
The recognition of antigenic peptides by CD4(+) helper T cells is demo
nstrated here to result in a dramatic (up to 90%) decrease in expressi
on of major histocompatibility complex (MHC) class II molecules on the
surface of antigen-presenting cells (APC). The reduction is selective
to the class II isotype presenting the antigen, but if affects both a
llelic forms of the same isotype in heterozygous APC. The observed MHC
down-regulation requires a specific T cell receptor-peptide-class II
interaction, a direct contact between T cell and APC, and the involvem
ent of CD2 molecules. These findings have important implications for t
he regulation of immune response, self tolerance, and autoimmunity.