Hierarchal utilization of different T-cell receptor Vbeta gene segments in the CD8(+)-T-cell response to an immunodominant Moloney leukemia virus-encoded epitope in vivo.
The CD8(+)-T-cell response to Moloney murine leukemia virus (M-MuLV)-associated antigens in C57BL/6 mice is directed against an immunodominant gag-encoded epitope (CCLCLTVFL) presented in the context of H-2D(b) and is restricted primarily to cytotoxic T lymphocytes (CTL) expressing the Valpha3.2 and Vbeta5.2 gene segments. We decided to examine the M-MuLV response in congenic C57BL/6 Vbeta(a) mice which are unable to express the dominant Valpha3.2(+) Vbeta5.2(+) T-cell receptor (TCR) due to a large deletion at the TCR locus that includes the Vbeta5.2 gene segment. Interestingly, M-MuLV-immune C57BL/6 Vbeta(a) mice were still able to reject M-MuLV-infected tumor cells and direct ex vivo analysis of peripheral blood lymphocytes from these immune mice revealed a dramatic increase in CD8(+) cells utilizing the same Valpha3.2 gene segment in association with two different Vbeta segments (Vbeta3 and Vbeta17). Surprisingly, all these CTL recognized the same immunodominant M-MuLV gag epitope. Analysis of the TCR repertoire of individual M-MuLV-immune (C57BL/6 x C57BL/6 Vbeta(a))F(1) mice revealed a clear hierarchy in Vbeta utilization, with a preferential usage of the Vbeta17 gene segment, whereas Vbeta3 and especially Vbeta5.2 were used to much lesser extents. Sequencing of TCRalpha- and -beta-chain junctional regions of CTL clones specific for the M-MuLV gag epitope revealed a diverse repertoire of TCRbeta chains in Vbeta(a) mice and a highly restricted TCRbeta-chain repertoire in Vbeta(b) mice, whereas TCRalpha-chain sequences were highly conserved in both cases. Collectively, our data indicate that the H-2D(b)-restricted M-MuLV gag epitope can be recognized in a hierarchal fashion by different Vbeta domains and that the degree of beta-chain diversity varies according to Vbeta utilization.
Brawand
P
P
Ludwig Institute for Cancer Research, Lausanne Branch, 1066 Epalinges, Switzerland.
Cerottini
J C
JC
MacDonald
H R
HR
D000595:Amino Acid Sequence; D000818:Animals; D003592:Cytophotometry; D003601:Cytotoxicity Tests, Immunologic; D003602:Cytotoxicity, Immunologic; D005434:Flow Cytometry; D015683:Gene Products, gag / Q000276:immunology*; D019674:Genes, T-Cell Receptor beta; D007114:Immunization; D016056:Immunodominant Epitopes / Q000276:immunology*; D019041:L-Selectin / Q000378:metabolism; D051379:Mice; D008969:Molecular Sequence Data; D008979:Moloney murine leukemia virus / Q000235:genetics / Q000276:immunology*; D016133:Polymerase Chain Reaction / Q000379:methods; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000737:chemistry / Q000235:genetics / Q000276:immunology*; D017422:Sequence Analysis, DNA; D013602:T-Lymphocytes, Cytotoxic / Q000276:immunology*; D014407:Tumor Cells, Cultured
D015683:Gene Products, gag; D016056:Immunodominant Epitopes; D016693:Receptors, Antigen, T-Cell, alpha-beta; D019041:L-Selectin