Mouse strain variation in Ly-24 (Pgp-1) expression by peripheral T cells and thymocytes: implications for T cell differentiation.
The cell surface glycoprotein Ly-24 has been proposed as a useful marker for the identification of in vivo-primed T cells. Analysis of Ly-24 surface expression by T cells from different mouse strains has shown variation in Ly-24 expression that is not H-2 linked; however, mice of the Ly-24.1 allele (e.g. BALB/c) express relatively high amounts, whereas Ly-24.2 strains (e.g. C57BL/6) are low expressors. In BALB/c (Ly-24 high) and C57BL/6 (Ly-24 low) mice, Ly-24 was expressed by both CD4- CD8+ and CD4+ CD8- subpopulations of single-positive T cells and thymocytes Among CD4- CD8- thymocytes, the overall expression of Ly-24 was similar in both mouse strains. Analysis of CD4+ and CD8+ single-positive thymocytes from newborn and adult BALB/c mice showed that the neonatal population contained fewer Ly-24+ cells. However, using the cell surface markers J11d and CD3, neonatal single-positive thymocytes were found to contain larger numbers of cells with the Ly-24-J11d+CD3 low to negative phenotype. Taken together, these results show that in BALB/c (Ly-24 high) mice, as soon as functional mature phenotype (CD3+) CD4+ and CD8+ single-positive thymocytes are generated, they already express Ly-24. These data cast doubt on the usefulness of Ly-24 expression as a universal marker of in vivo-primed T cells and suggest that in BALB/c mice thymus migrants may well be Ly-24+. Expression of Ly-24 by thymocytes is discussed in the context of current models of intrathymic T cell differentiation.
Lynch
F
F
Department of Experimental Pathology, John Curtin School of Medical Research, Canberra, Australia.
Ceredig
R
R
D000375:Aging; D000818:Animals; D000950:Antigens, Ly / Q000032:analysis*; D002454:Cell Differentiation; D008562:Membrane Glycoproteins / Q000032:analysis*; D051379:Mice; D008806:Mice, Inbred AKR; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008811:Mice, Inbred DBA; D013045:Species Specificity; D013601:T-Lymphocytes / Q000276:immunology* / Q000502:physiology; D013950:Thymus Gland / Q000196:embryology / Q000254:growth & development / Q000276:immunology*
D000950:Antigens, Ly; D008562:Membrane Glycoproteins