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.
Hamad
M
M
Department of Biological Science, University of Tulsa, Oklahoma 74104.
Klein
J R
JR
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