Phosphoproteins recognized by an H-2-linked immune response gene and their association with cell proliferation.

An H-2-associated immune response gene which maps to the I-A subregion of the H-2 complex governs the ability of H-2 congenic mice to mount an antibody response to five phosphoproteins with molecular weights of 33,000, 29,000, 23,000, 17,000, and 16,000 when inoculated with BW5147, a spontaneous AKR T-cell leukemic cell line. The phosphoproteins are present in all tumor cell lines tested, including those of murine and human origins. The phosphoproteins are associated with the proliferative state of the cell as studied in many systems including growth stimulation of normal lymphoid cells with mitogens, interleukin 2 dependency for growth of a cloned T-cell line, cessation of proliferation by serum starvation of Swiss 3T3 fibroblasts, retention of the proliferative capacity of SV40-transformed 3T3 fibroblasts, and the differentiation and inhibition of proliferation of human promyelocytic leukemic cells. Phosphoproteins with molecular weights of 33,000, 29,000, 23,000, 17,000, and 16,000 are therefore not specific to a particular inducible cellular pathway but are associated with cell proliferation in general.