In vitro stimulation of human peripheral blood B cells from normal individuals by activated T cells increases the efficiency of hybridoma generation

Peripheral blood B cells from normal individuals have been less than ideal as a resource for “fusible” cells for the generation of human hybridoma antibodies. In vitro stimulation of normal peripheral blood B cells by CD4+ T cells (HUT 78) that had been activated by a solid phase anti-CD3 monoclonal antibody (OKT3) was investigated to see if differentiation of B cells would result in an increased pool of B cells that could be immortalized. A comparison of the rate of successful fusion, an estimation of the frequency of the fusible cells from the input peripheral blood, and the amount of immunoglobulin secreted both in vitro, prior to fusion, and by the resulting clones in two different in vitro immunization protocols, with and without activated T cells indicated that inclusion of the activated T cells provided the necessary help to drive the B cells to a fusible state. Stimulation by activated T cells improves the efficiency of generating B cell hybrid clones from peripheral blood 10-fold compared to in vitro immunization with antigen alone.