Characterization of guinea pig mitogenic factors. I. Evidence that antigen-induced mitogenic factor and mitogenic factor from mixed leukocyte cultures are distinct molecular entities.
Mitogenic factor from BCG-sensitized cells stimulated with antigen (PPD) was found to have a m.w. between 20 and 25,000 daltons and an isoelectric point of about 7.5. The blastogenic activity of this factor was not affected by L-fucose or heating at 56 degrees C for up to 1 hr. Mitogenic factor obtained from supernatants of allogeneic cell mixtures (MLC-MF) on the other hand, had a m.w. at 15 to 18,000 daltons and an isoelectric point of 6.5. The blastogenic activity of MLC-MF was inhibited by 0.1 M L-fucose. The factor was stable at 56 degrees C for 1 hr. An antibody prepared against MLC-MF inhibited the MLC reaction as well as the activity of MLC-MF on non-committed cells. This antibody, however, did not affect the response of lymphocytes to PHA or PPD and had no suppressive effect on PPD-MF. The antibody was not cytotoxic and its suppressive activity in the MLC response could not be absorbed out by lymphoid cells indicating that it is probably directed against a lymphocyte activation product (MLC-MF) rather than membrane antigens. The chemical and immunologic differences exhibited by PPD-MF and MLC-MF indicate that these two lymphokines are distinct molecular entities.
D000818:Animals; D000906:Antibodies; D000941:Antigens; D005643:Fucose / Q000494:pharmacology; D006168:Guinea Pigs; D006358:Hot Temperature; D007428:Intradermal Tests; D007525:Isoelectric Focusing; D007959:Lymphocyte Culture Test, Mixed; D008934:Mitogens / Q000032:analysis*; D008970:Molecular Weight; D011817:Rabbits; D014373:Tuberculin
D000906:Antibodies; D000941:Antigens; D008934:Mitogens; D014373:Tuberculin; D005643:Fucose