Human lymphocyte-mouse myeloma somatic cell hybrids: selective hybrid formation

Human T cell hybridomas secreting immune interferon

Human T-cell hybridomas were established by hybridization of concanavalin A-stimulated human peripheral blood lymphocytes with a 6-thioguanine-resistant mutant cell line, designated SH9, derived by irradiation from a cloned human cutaneous T lymphoma line, Hut102-B2. High levels of interferon (IFN) were demonstrated in the supernatants of hybridoma L265 and its subclones. Whereas no IFN was detected in SH9 cell cultures, up to 1,330 units of IFN per ml were produced spontaneously by the hybrids. On induction with 12-omicron-tetradecanoylphorbol 13-acetate, IFN synthesis in hybridoma cultures was enhanced 8- to 16-fold. Neutralization with specific antisera and determination of antiviral activities in human and bovine cells showed that the IFN secreted by the hybridomas was immune IFN (IFN-gamma). Analysis of DNA content, karyotype, and cell surface phenotype, including T cell specific antigens and receptors, confirmed the T cell hybrid nature of L265 clones. No correlation was found in the hybridomas between IFN production and the expression of HTLV, a retrovirus released by Hut102-B2 and SH9 cells.

Expression of spleen cell immunoglobulin phenotype in hybrids with myeloma cell lines

Fusions were performed between myeloma cell lines, of mouse and rat origin, and mouse or rat spleen cells. Two statistical methods have been used to measure the proportion of hybrids expressing a spleen cell-derived immunoglobulin phenotype, one of them applicable to cells growing under nonlimiting dilution conditions. The results indicate that there is strong preferential selection for hybrid cell growth with an immunoglobulin-secreting phenotype. The degree of preferential selection is dependent upon the myeloma cell line used and is most marked in the case of the rat myeloma lines. Surviving hybrids seem to originate from fusions of myeloma and spleen B(but not T) cells, but immunoglobulin production is lost more readily in certain combinations.