LYMPHOCYTE SURFACE - DIFFERENCES IN SURFACE-CHEMISTRY OF MURINE SPLEEN T LYMPHOCYTES OF VARYING MAJOR HISTOCOMPATIBILITY HAPLOTYPES

Spleen lymphocytes and erythrocytes from congenic mice of different m.h.c. haplotypes were characterized on a biophysical basis (the anodic electrophoretic mobility, e.p.m.) to correlate any subtle differences in the cell surface topochemistry with the H-2 specificity. Spleen T lymphocytes from A.CA (H-2(f)) and A.SW (H-2(s)) mice exhibited high values of e.p.m., which were significantly different. In contrast, significant differences in the e.p.ms of B cells and erythrocytes of the two m.h.c. haplotypes were not observed. Cell electrophoresis of live, intact T lymphocytes of spleen (without the 'contaminating' B cells), before and after the chemical modification of the cell surface by treatment with small, non-toxic concentrations of maleic anhydride (MA), showed the number of lysine side chain amino groups of surface membrane proteins of cells with H-2(f) specificity to be about twice that on cells with H-2(s) specificity. Such a difference was observed both in the case of T lymphocytes from cyclophosphamide-treated mice, and the effluent from nylon wool columns. The difference in the number of the cationogenic amino groups (-NH2 + H+ ⇆ -NH3+) in the cell periphery (within about 1 nm of the cell surface in physiological saline), contributing a positive charge, would explain the observed difference in the e.p.ms of H-2(f) and H-2(s) spleen T lymphocytes. An interpretation of the data is that the macromolecules coded by the H-2 genes or other genes under H-2 control might be responsible for delicate differences in the chemical composition of the surface membranes of cells of the two m.h.c. haplotypes, detectable only on high e.p.m. lymphocytes of spleen (T or T-like cells). The possibilities of other factors influencing the observed differences in the surface chemistry are discussed.