IV3α(NeuGcα2-8NeuGc)-Gg4Cer is restricted to CD4+ T cells producing interleukin-2 and a small population of mature thymocytes in mice

Abstract

Monoclonal antibody YK-3 was established by immunization with IV3α(NeuGcα2-8NeuGc)-Gg4Cer (G(D1c)-(NeuGc-NeuGc-)), and its epitope was determined to be NeuGcα2-8NeuGcα2-3Galβ1. Thin layer chromatography immunostaining with YK-3 detected only G(D1c)-(NeuGc-NeuGc-) among the gangliosides of mouse thymocytes and splenocytes. Immunohistochemical staining with YK-3 visualized the medulla of mouse thymus and T cell- dependent areas of mouse spleen and mesenteric lymph nodes. Two-color flow cytometry demonstrated that G(D1c)(NeuGc-NeuGc-) was expressed on a quarter of CD3+ mature thymocytes and strongly expressed on three quarters of CD4+ T cells in the spleen, lymph nodes, and peripheral blood but not on CD8+ T cells or B cells. G(D1c)(NeuGc-NeuGc-)-positive cells and negative cells were separated by panning with YK-3 on Petri dishes into adherent and nonadherent fractions. Following stimulation with concanavalin A, adherent cells, predominantly G(D1c)(NeuGc-NeuGc-)+, produced more interleukin-2 (IL-2) and markedly less interleukin-4 (IL-4) than nonadherent cells. This conclusion is supported by data obtained by lysis of cells by YK-3 and complement. These data indicate that the cell surface expression of G(D1c)(NeuGc-NeuGc-) is restricted to a small number of mature thymocytes and a subset of CD4+ T cells, which produce abundant IL-2 and very little IL-4, suggesting that G(D1c)(NeuGc-NeuGc-) is an excellent marker for mouse naive T or T helper 1- like cells in vivo.