Special functional features of T-lymphocyte subpopulations in the effector compartment of the intestinal mucosa and their relation to mucosal transformation.
Recent studies indicate that intestinal lamina propria T cells are highly specialized lymphocytes, which differ from T cells in other compartments of the immune system in several respects. In the present study phenotypic and functional characteristics of lamina propria T cells and their possible relation to mucosal growth will be discussed. Lymphocytes from human and nonhuman primate intestine were isolated by an enzymatic procedure. Lymphocytes were studied using dual-color immunofluorescence (FACS) and functional in vitro assays. CD4 positive (helper-) lamina propria T-cells lack the CD45RA antigen and express the CD45RO antigen. This phenotype is characteristic for memory T cells. In addition intestinal T cells express IL-2 receptors and IL-2 receptor mRNA, and are able to synthesize high amounts of IL-2. Functional studies in nonhuman primates infected rectally with Chlamydia trachomatis have shown that lamina propria T cells do not proliferate after stimulation with antigen but rather provide helper function for immunoglobulin synthesis. The intestinal lamina propria therefore contains highly specialized T cells which have the phenotype of memory T cells and which are activated. Functionally these T cells can be characterized as differentiated effector lymphocytes. Recent studies from other laboratories have shown that the pattern of lymphokines produced by lamina propria T cells and the responsiveness to certain lymphokines also differ from those of other lymphocyte populations. Since T-cell-derived lymphokines are also important regulators for epithelial growth and differentiation as well as for connective tissue metabolism, lamina propria T cells might be of major importance in mucosal growth and transformation.
Zeitz
M
M
Department of Gastroenterology, Klinikum Steglitz, Free University of Berlin.
Schieferdecker
H L
HL
James
S P
SP
Riecken
E O
EO
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D005455:Fluorescent Antibody Technique; D006801:Humans; D016130:Immunophenotyping; D007413:Intestinal Mucosa / Q000254:growth & development / Q000276:immunology*; D008213:Lymphocyte Activation / Q000276:immunology; D016176:T-Lymphocyte Subsets / Q000276:immunology*
D000945:Antigens, Differentiation, T-Lymphocyte