Phenotypic and functional heterogeneity of murine intestinal intraepithelial lymphocytes defined by cell density: implications for route of differentiation and responsiveness to proliferation induction.
The phenotype and function of murine intestinal intraepithelial lymphocytes (IEL) was studied in a Percoll-fractionated preparation that consisted of low-density cells which migrated to the 40-50% Percoll interface (IEL-40), medium-density cells which migrated to the 50-55% interface (IEL-50), and high-density cells which migrated to the 55-70% interface (IEL-55). IEL-40 and IEL-50 cells, the subsets phenotypically most similar to mature IEL, consisted of CD3+ T cells that included CD4- CD8+ and CD4+ CD8+ cells; CD4+ CD8- cells were present only in the IEL-50 fraction. T-cell receptor (TcR)alpha beta and TcR gamma delta cells were present in both IEL-40 and IEL-50 fractions. In contrast, most IEL-55 were CD3-, heat-stable antigen (HSA)+ cells that were not B cells; some IEL-55 cells were CD3lo HSA- or CD3lo HSA+ suggesting that IEL-55 are immature T cells. TcR alpha beta but not TcR gamma delta was expressed in the IEL-55 fraction. All three IEL fractions consisted of both CD8 alpha alpha and CD8 alpha beta cells. There was considerable functional heterogeneity between the three IEL fractions such that CD3-induced proliferation was greatest for IEL-50 cells and least for IEL-55 cells; that activity correlated with the proportion of Thy-1+ cells within the fractions. Both IEL-40 and IEL-50 fractions contained activated cytotoxic T lymphocytes (CTL) that were 8-16-fold more lytic than IEL-55 cells. That IEL-55 cells may be precursors of some IEL-40 and IEL-50 cells was demonstrated by a shift in cell density and by an increase in proportions of cells expressing markers of IEL-40 and IEL-50 cells following in vitro stimulation via CD3. The relevance of these findings to differences in functional activities reported for murine IEL is discussed.
Department of Biological Science, University of Tulsa, Oklahoma 74104.
M
M
Hamad
J R
JR
Klein
D000818:Animals; D000954:Antigens, Surface / Q000032:analysis; D017252:CD3 Complex / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology; D002455:Cell Division / Q000276:immunology; D002499:Centrifugation, Density Gradient; D003602:Cytotoxicity, Immunologic; D004848:Epithelium / Q000276:immunology; D007413:Intestinal Mucosa / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008811:Mice, Inbred DBA; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000032:analysis; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000032:analysis; D013154:Spleen / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D000954:Antigens, Surface; D017252:CD3 Complex; D016693:Receptors, Antigen, T-Cell, alpha-beta; D016692:Receptors, Antigen, T-Cell, gamma-delta