MHC Specified Lymphocyte Activating and Suppressor Activating Determinants in Human Mixed Lymphocyte Reactions

Abstract

The presence of HLA-linked Sad/s [suppressor activating determinants] on a [human] homozygous typing cell (HTC) FPA (8W321) was shown. When it was used to type the P family, which included an HLA-B/DR recombinant sibling, its genes mapped towards the HLA-B-A end of the HLA haplotype separate from HLA-D/DR and was associated with HLA-Bw35 homozygosity. This same recombinant maps the C4 complement genes on the HLA-D/DR end of the chromosome away from HLA-B. The suppressor T cell subpopulation which was activated by the Sad of this consanguineous HTC FPA was left behind after separating the OKT4 positive cells with a monomorphic [mouse] monoclonal anti-T cell antibody (OKT4). These OKT4 positive cells reacted normally in MLC [mixed lymphocyte culture] to the FPA Lad [lymphocyte activating determinants] Fes 6. At least part of the genetic control of suppressor recognition apparently is outside the HLA complex.