Signal transduction by different forms of the γδ T cell-specific pattern recognition receptor WC1.
WC1 coreceptors are scavenger receptor cysteine-rich (SRCR) family members, related to T19 in sheep, SCART in mice, and CD163c-α in humans, and form a 13-member subfamily in cattle exclusively expressed on γδ T cells. Subpopulations of γδ T cells are defined by anti-WC1 mAbs and respond to different pathogen species accordingly. In this study, variegated WC1 gene expression within subpopulations and differences in signaling and cell activation due to endodomain sequences are described. The endodomains designated types I to III differ by a 15- or 18-aa insert in type II and an additional 80 aa containing an additional eight tyrosines for type III. Anti-WC1 mAbs enhanced cell proliferation of γδ T cells when cross-linked with the TCR regardless of the endodomain sequences. Chimeric molecules of human CD4 ectodomain with WC1 endodomains transfected into Jurkat cells showed that the tyrosine phosphorylation of the type II was the same as that of the previously reported archetypal sequence (type I) with only Y24EEL phosphorylated, whereas for type III only Y199DDV and Y56TGD were phosphorylated despite conservation of the Y24EEL/Y24QEI and Y199DDV/I tyrosine motifs among the three types. Time to maximal phosphorylation was more rapid with type III endodomains and sustained longer. Differences in tyrosine phosphorylation were associated with differences in function in that cross-linking of type III chimeras with TCR resulted in significantly greater IL-2 production. Identification of differences in the signal transduction through the endodomains of WC1 contributes to understanding the functional role of the WC1 coreceptors in the γδ T cell responses.
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003; and.
Chuang
C
Chen
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003; and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003.
Haoting
H
Hsu
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003; and.
Edward
E
Hudgens
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003; and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003 cbaldwin@vasci.umass.edu telfer@vasci.umass.edu.
Janice C
JC
Telfer
Department of Veterinary and Animal Sciences, University of Massachusetts, Amherst, MA 01003; and Program in Molecular and Cellular Biology, University of Massachusetts, Amherst, MA 01003 cbaldwin@vasci.umass.edu telfer@vasci.umass.edu.
Cynthia L
CL
Baldwin
D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000494:pharmacology; D015703:Antigens, CD / Q000235:genetics / Q000276:immunology; D015214:Antigens, Differentiation, Myelomonocytic / Q000235:genetics / Q000276:immunology; D002417:Cattle; D057809:HEK293 Cells; D006801:Humans; D007376:Interleukin-2 / Q000235:genetics / Q000276:immunology; D019169:Jurkat Cells; D008562:Membrane Glycoproteins / Q000235:genetics / Q000276:immunology*; D051379:Mice; D010766:Phosphorylation / Q000187:drug effects / Q000276:immunology; D017434:Protein Structure, Tertiary; D016692:Receptors, Antigen, T-Cell, gamma-delta / Q000235:genetics / Q000276:immunology*; D011956:Receptors, Cell Surface / Q000235:genetics / Q000276:immunology; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics / Q000276:immunology*; D013601:T-Lymphocytes / Q000166:cytology / Q000276:immunology*; D000098902:CD163 Antigen
D058846:Antibodies, Monoclonal, Murine-Derived; D015703:Antigens, CD; D015214:Antigens, Differentiation, Myelomonocytic; D000098902:CD163 Antigen; C086500:DMBT1 protein, Bos taurus; D007376:Interleukin-2; D008562:Membrane Glycoproteins; D016692:Receptors, Antigen, T-Cell, gamma-delta; D011956:Receptors, Cell Surface