Multiple subsets of anti-tetanus toxoid antibody-producing cells in human peripheral blood differ by size, expression of membrane receptors, and mitogen reactivity
Thiele, C.J.; Morrow, C.D.; Stevens, R.H.
Journal of Immunology 126(3): 1146-1153
1981
ISSN/ISBN: 0022-1767 PMID: 6970218 Document Number: 181974
Mitogenic reactivity, unit gravity sedimentation, surface membrane phenotype, and in vivo booster immunization were used to delineate B cell subsets that secrete anti-tetanus toxoid antibody (Ig-Tet) in vitro. These subsets were characterized by their in vitro reactivity to pokeweed mitogen (PWM), bacterial -Ia+, were detected in the circulation and produced IgG-Tet without T cell or mitogen stimulation during a 3 day culture period. These cells were consistently the fastest sedimenting B cell subset observed, ranging from 6-12 mm/h. These cells also showed considerable size heterogeneity and required DNA synthesis for maximum antibody production. IgM anti-tetanus toxoid antibody (IgM-Tet) synthesis was detected in B cells cultured with PWM-stimulated T cells and was not dependent on recent in vivo booster immunization. The majority of IgM-Tet synthesis was by cells bearing the phenotype .mu.+ .delta.+ Fc.gamma.R .+-. Ia+. By 12 days after immunization, IgG-Tet synthesis was only detected in PWM- or PPD-stimulated B and T cell cultures. The majority of IgG-Tet produced by PWM-reactive B cells had the phenotype Ig+CR+Fc.gamma.R-Ia+, yet they were heterogeneous in their expression of .mu. and .delta. PWM-stimulated IgG-Tet production occurred over a narrow range of sedimentation velocities (4-6 mm/h) that were slightly faster than the majority of the B cells (2-4 mm/h). Total Ig stimulated by PWM gave a similar profile, but faster sedimenting cells (8-12 mm/h) were found in some donors. LPS primarily stimulated Ig production in cells that sedimented slightly faster than the majority of B cells. The surface phenotype of LPS-reactive cells was similar to the PWM-reactive cells, i.e., Ig+Cr+Fc.gamma.R-Ia+. Little IgG-Tet was detected by LPS stimulation of lymphocyte cultures of 2-wk immunized donors, suggesting that differences between LPS- and PWM-reactive cells exist in vivo. PPD stimulated at least 2 B cell subsets. One subset sedimented between 8 and 12 mm/h and secreted IgG-Tet, whereas a 2nd was found primarily in the 2-6 mm/h velocities and synthesized total IgG. The phenotype of PPD-induced B cells that synthesized the majority of IgM and IgG and IgG-Tet was .mu.+.delta.-CR+Fc.gamma.R. The absence of surface membrane IgD thus distinguished PPD-reactive from PWM-reactive IgG- Tet-producing cells.