UNIQUE T-CELL DIFFERENTIATION MARKERS - GANGLIOSIDES WITH CHOLERA-TOXIN RECEPTOR ACTIVITY ON MURINE FETAL THYMOCYTES

Cholera toxin B subunit receptors (CTBR; gangliosides GM1a and GM1b-Ga lNAc-Gal) and GM1b-type gangliosides were examined during T cell devel opment in BALB/c mice by FACS or TLC immunostaining. Sixty-two percent of CD4(-)8(-) early fetal thymocytes express CTBR [58% low affinity ( GM1a(+)), 4% high affinity (GM1a(2+))] at 13 days gestation (Day 13); GM1a(2+) was expressed preferentially on Thy-1(+) fetal thymocytes aft er Day 13. GM1a(2+) Thy-1(+) cells increased from 4% on Day 13 to 95% on Day 17. Surface GM1a(2+) decreased beginning on Day 15 while GM1b-G alNAc-Gal (and CD4 and CD8) increased. GM1b-type(+) cells increased fr om 8% on Day 13 to 51% on Day 17 and then decreased to 16% at 4 weeks; few asialo GM1(+) cells (<5%) are seen during gestation. Thus, synthe sis of GM1a- and GM1b-type series was active until Days 15 and 17, res pectively, and then was suppressed; GM1b-GalNAc-Gal was synthesized fr om GM1b following Gestational Day 15. GM1a- and GM1b-type identify imm ature T cells in mice, while GM1b-GalNAc-Gal identifies mature T cells . (C) 1994 Academic Press, Inc.