T-cell receptor variable beta genes show differential expression in CD4 and CD8 T cells.
Studies in transgenic and inbred strains of mice have shown that the critical molecular interactions controlling positive selection involve major histocompatibility complex (MHC), T-cell receptor (TCR), and CD4 or CD8 coreceptor molecules. Correlations have been established between MHC gene products and the percentage of CD4 or CD8 T cells that express specific variable (V) beta-gene products as part of the alpha beta heterodimer. These studies have important implications regarding potential mechanisms of HLA-linked autoimmune diseases in humans. If similar interactions are required for positive selection in humans, one would predict that the TCR repertoire expressed by mature, peripheral blood CD4 and CD8 T cells would vary. To test this hypothesis the expression of specific TCR V beta-region genes by CD4 and CD8 T cells from healthy individuals was compared using both triple-color flow cytometry and polymerase chain reaction based experimental approaches. The results show that the TCR repertoire does vary as a function of CD4 and CD8 T-cell subsets. Among unrelated individuals certain V beta genes were consistently overrepresented in the CD4 population (V beta-5.1, -6.7a, and -18); some were skewed to the CD8 population (V beta-14) while others showed variable patterns (V beta-12 and -17). Deletion of entire V beta gene families was not observed suggesting that this is a rare event in humans. Attempts to correlate the expressed TCR repertoire in humans with HLA alleles will require consideration of these differences in expression as a function of subset.
Department of Veterans Affairs Medical Center, Portland, OR 97207.
M P
MP
Davey
M M
MM
Meyer
D D
DD
Munkirs
D
D
Babcock
M P
MP
Braun
J B
JB
Hayden
A C
AC
Bakke
D000911:Antibodies, Monoclonal; D001483:Base Sequence; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D002851:Chromatography, High Pressure Liquid; D004247:DNA / Q000032:analysis; D005434:Flow Cytometry; D015870:Gene Expression; D014644:Genetic Variation; D006801:Humans; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics*; D050378:T-Lymphocytes, Regulatory / Q000276:immunology*
D000911:Antibodies, Monoclonal; D016693:Receptors, Antigen, T-Cell, alpha-beta; D004247:DNA