title: Implication of gammadelta T cells in the human immune response to cytomegalovirus.
abstract: In normal individuals, gammadelta T cells account for less than 6% of total peripheral T lymphocytes and mainly express T-cell receptor (TCR) Vdelta2-Vgamma9 chains. We have previously observed a dramatic expansion of gammadelta T cells in the peripheral blood of renal allograft recipients only when they developed cytomegalovirus (CMV) infection. This increase was long lasting (more than 1 year), was associated with an activation of gammadelta T cells, and concerned only Vdelta1 or Vdelta3 T-cell subpopulations. Analysis of gammadelta TCR junctional diversity revealed that CMV infection in these patients was accompanied by (a) a marked restriction of CDR3 size distribution in Vdelta3 and, to a lesser extent, in Vdelta1 chains; and (b) a selective expansion of Vdelta1 cells bearing recurrent junctional amino acid motifs. These features are highly suggestive of an in vivo antigen-driven selection of gammadelta T-cell subsets during the course of CMV infection. Furthermore, Vdelta1 and Vdelta3 T cells from CMV-infected kidney recipients were able to proliferate in vitro in the presence of free CMV or CMV-infected fibroblast lysates but not uninfected or other herpes virus-infected fibroblast lysates. This in vitro expansion was inhibited by anti-gammadelta TCR mAb's. These findings suggest that a population of gammadelta T cells might play an important role in the immune response of immunosuppressed patients to CMV infection.
mesh_terms: D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001483:Base Sequence; D002648:Child; D003587:Cytomegalovirus / Q000276:immunology*; D003586:Cytomegalovirus Infections / Q000209:etiology / Q000276:immunology; D017931:DNA Primers / Q000235:genetics; D005260:Female; D006801:Humans; D066298:In Vitro Techniques; D016030:Kidney Transplantation / Q000009:adverse effects / Q000276:immunology; D008213:Lymphocyte Activation; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000378:metabolism*; D016176:T-Lymphocyte Subsets / Q000276:immunology*; D013997:Time Factors