MHC class II gene products specific autoreactive T cell clones provide inducer as well as amplifier function for B cell Ig production.

Autoreactive T lymphocytes were generated by culturing human peripheral blood mononuclear cells with an antigen-specific/MHC restricted autologous inducer T cell, termed RW17C and subsequently cloned in soft agar. The majority of such clones expressed the T3+T4+T8-T11+Ia+ phenotype and were directed at autologous class II MHC gene products found on B cells, macrophages and B lymphoblastoid cells as judged by their proliferative response to the latter. For this recognition, the clones employed a T3-Ti molecular complex and a T4 structure analogous to those found on allospecific T cells. Perhaps more importantly, it was observed that the same AC (autoreactive clone) induced autologous B cells to produce high levels of immunoglobulin in the absence of exogenous antigen and could synergize with the RW17C clone to effect maximal B cell Ig production. In addition, supernatant from T3-Ti triggering of AC clone induced both polyclonal proliferation and differentiation of small B lymphocytes. These results support the notion that such autoreactive cells can function in a physiologic amplifier role by facilitating induction via an internal set of signals (i.e. autologous MHC).