Enhancement of Lymphocyte Proliferation and Il-2 Receptor Expression by A Processed Form (Gm-1/P) of Monosialoganglioside GM-1

Abstract

In this study we investigated the ability of GM-l/P, a calcium mediated processed form of monosialoganglioside GM-1, of in vivo augmenting mouse T and B-lymphocyte blastogenesis induced by mitogens. We have also determined its effect on IL-2 responsiveness by analyzing the induction of the expression of IL-2 receptor (IL-2r) on mouse spleen cells. Lymphocyte blastogenesis was evaluated by 3H-TdR incorporation of spleen cells from untreated or GM-l/P (lmg/Kg, i.v., day-1) treated mice cultured in the presence of T (PHA, ConA) B (LPS) cell specific mitogens. the stimulatory effects appeared to be due to a direct action on T and B lymphocytes, since proliferative response was not abolished by removal of macrophages. Splenocytes from GM-l/P treated mice showed increased proliferation in response to various concentrations of HrIL-2; moreover under these conditions an increased generation of LAK activity was found. A direct evidence for enhanced expression of IL-2r was obtained by immunofluorescence and FACS analyeis using a monoclonal antibody (PC. 61) directed against the p55 subunit of murine IL-2r. 29% PC. 61+ cells were found in IL-2 cultures from treated spleen cells.