Modulation of human antibody production in vitro by D-penicillamine and CuSO4: inhibition of helper T cell function.

Pokeweed mitogen (PWM), a T cell dependent, polyclonal B cell activator, stimulates the differentiation of immunoglobulin secreting cells (ISC) from normal human peripheral blood mononuclear cells (PBM). In this in vitro study, PBM failed to generate ISC in response to PWN after brief exposure to penicillamine and CuSO4; preincubation with either penicillamine or CuSO4 alone had no effect. Experiments utilizing purified populations of B and T cells indicated that penicillamine and CuSO4 markedly inhibited helper T cell activity but not B cell function. These observations may explain the effectiveness of penicillamine in rheumatoid arthritis, especially in decreasing rheumatoid factor titers.