Human cell lines secreting lymphokines. II. BCGF production by a T hybridoma and B cell lines.

B cell growth factor (BCGF) is a lymphokine (LK) primarily produced and secreted by activated T cells. This LK induces proliferation of B cells in culture and can maintain continuous growth of human B cells. One of the putative uses of this factor might be the establishment of monoclonal B cell lines which secrete specific antibodies. These antibodies could be used for passive immunization or in vivo immunodiagnostics. As conventional mitogen activation of T cells induces the secretion of many factors, some of them with opposite effects, the approach taken by us and others was to establish monoclonal hybridomas which produce constitutively a single factor. Such a human T-T cell hybridoma (TH-5), has been established and is growing and secreting constitutively BCGF for the tested 18 months. This BCGF induces proliferation of human B-cells without the requirement of B cell preactivation. No secretion of interleukin-2 or gamma-interferon by this hybridoma was detected. Furthermore, no influence of this factor was detected on T cells. Under optimal growth conditions, the generation time of this hybridoma is 16 hours and it reaches a maximum concentration of 3 X 10(6) cells/ml. The hybridoma cells could grow in serum-free-media and secrete BCGF for a limited time. The produced BCGF was found to be stable for the four tested months at -20 degrees C, at least one week at 4 degrees C and several hours at 37 degrees C. Its activity was destroyed at pH 2.(ABSTRACT TRUNCATED AT 250 WORDS)