title: Subsets of Lyt-2+ cells defined by differential expression of the 9F3 antigen: alterations in mice of the lpr/lpr genotype.
abstract: Recently, we found that a novel murine cell surface antigen recognized by the 9F3 monoclonal antibody demonstrates T cell heterogeneity in normal mice and in congenic strains homozygous for the lymphoproliferation- and autoimmunity-inducing lpr gene. The objective of the present work was to further characterize this heterogeneity by studying the distribution of the 9F3 marker among Lyt-2+ T cells. By using dual parameter flow cytofluorometry analysis, at least two subsets of peripheral Lyt-2+ cells differing in 9F3 expression could be distinguished. In MRL/Mp-++, C57BL/6, and C3H/HeJ mice, 9F3- and 9F3+ cells accounted, respectively, for 65 to 80% and 20 to 35% of the whole Lyt-2+ population. Interestingly, in lpr/lpr-bearing congenic strains, a three- to fivefold selective increase in the frequency and absolute number of 9F3+ Lyt-2+ cells was found to take place during aging. Functional analysis of Lyt-2+ cells isolated by panning revealed that in +/+ mice, these cells respond better to phytohemagglutinin and concanavalin A than in lpr/lpr mice, indicating that phenotypic changes of Lyt-2+ cells correlate with functional changes. Further evidence for the functional relevance of 9F3-defined Lyt-2+ cell heterogeneity was provided by the study of sorted cells from +/+ mice, showing that 9F3- cells exhibit higher mitogenic reactivities than 9F3+ cells. This finding suggests that 9F3+ Lyt-2+ cells in +/+ and lpr/lpr mice are functionally homologous. Together, these data indicate that, in addition to the known expansion of a population of abnormal Lyt-2-T cells, mice of the lpr/lpr genotype have an alteration of their Lyt-2+ cell population, characterized by an imbalance of 9F3-defined subsets and decreased mitogenic reactivities.
mesh_terms: D000375:Aging; D000818:Animals; D000950:Antigens, Ly / Q000032:analysis*; D002478:Cells, Cultured; D004261:DNA Replication; D005260:Female; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D005819:Genetic Markers; D005838:Genotype; D007518:Isoantibodies; D008213:Lymphocyte Activation; D051379:Mice; D008815:Mice, Inbred Strains / Q000276:immunology*; D008817:Mice, Mutant Strains / Q000276:immunology*; D010641:Phenotype; D013045:Species Specificity; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*
chemical_list: D000950:Antigens, Ly; D005819:Genetic Markers; D007518:Isoantibodies; C029805:Lyt antibodies