Requirement of HLA compatibility between T- and B-cells in mitogen-induced in vitro immunoglobulin production.

The necessity for human leukocyte antigen (HLA) compatibility in T- and B-cells in the differentiation of B-cells into immunoglobulin-producing cells (Ig cells) was studied in cultured human lymphocytes stimulated with pokeweed mitogen. We found that, despite the histocompatibility antigen difference, allogeneic T-cells from healthy donors could help B-cells to differentiate into immunoglobulin-producing cells to almost the same degree as autologous T-cells. However, T-cells from an apparently healthy subject whose sister had died of severe combined immunodeficiency did not collaborate with HLA-incompatible allogeneic B-cells in vitro, although her T-cells collaborated with autologous B-cells as well as B-cells from a brother with identical HLA-A, -B and -D. This indicates that the mechanism which in normal cases overcomes HLA antigen incompatibility was defective in this case. It further indicates that one of the mechanisms necessary in B- and T-cell interaction requires HLA compatibility.