DATA-BASE ANALYSIS OF PROTEIN EXPRESSION PATTERNS DURING T-CELL ONTOGENY AND ACTIVATION

We have developed a data base of lymphoid proteins detectable by two-d imensional polyacrylamide gel electrophoresis. The data base contains two-dimensional patterns and derived information pertaining to polypep tide constituents of unstimulated and stimulated mature T cells and im mature thymocytes, single-cell-derived T- and B-cell clones, leukemia cells, and lymphoid cell lines. Using this data base, we have compared the protein constituents of mature T cells and immature thymocytes be fore and after mitotic stimulation. A subset of polypeptides that are induced in mature T cells following mitotic stimulation were found to be constitutively expressed in immature thymocytes. Other polypeptides exhibited differences in their expression between mature and immature thymocytes in a manner unrelated to proliferation. The identity of se veral constitutively expressed or mitotically induced proteins in lymp hoid cells was established by microsequencing. These initial findings point to significant differences in the molecular pathways leading to proliferation between mature and immature T cells. The construction of this database should facilitate further studies of lymphoid different iation and function.