Induction of Autoantibody-Producing Cells after the Coculture of Haptenated and Normal Human Mononuclear Leukocytes 1

Abstract

Abstract

The coculture of normal human peripheral blood mononuclear leukocytes (PBL) and autologous mononuclear leukocytes coupled to the trinitrophenyl (TNP) hapten (TNP-PBL) was found to induce a polyclonal activation of antibody-producing cells. The polyclonal activation of antibody-producing cells was demonstrated by detecting the induction of cells producing antibody to sheep red blood cells using a complement-dependent, direct, hemolytic plaque-forming cell (PFC) assay. A ratio of four normal to one haptenated mononuclear leukocyte was found to be optimal for inducing the polyclonal activation of antibody-producing cells in these cultures. The plaque-forming cell assay in these experiments utilized monolayers of indicator red cells. Further evidence for the polyclonal induction of antibody-producing cells by TNP-PBL was provided by demonstrating PFC on monolayers of not only sheep red blood cells, but also autologous human red cells, bromelain-treated autologous red cells, TNP-coupled human and sheep red cells, and human autologous red cells coupled to human heat-aggregated IgG with chromic chloride. Thus cells secreting antibody to TNP, human red cells, and human IgG were induced. Anti-IgG and anti-human red cell-producing cells were first detected on Day 2 of culture and were still present on Day 9. Mononuclear leukocytes altered by chemical haptenation polyclonally stimulate normal mononuclear leukocytes to become antibody-producing cells. This polyclonal stimulation of antibody-producing cells includes cells producing antibodies to human IgG and human autologous red blood cells suggesting that autoantibody-producing cells are induced.