Clonal predominance, but preservation of a polyclonal reservoir, in the normal alpha beta T-cell repertoire.
We recently demonstrated that the peripheral gamma delta T-cell repertoire becomes oligoclonal with increasing age. Although this junctional homogeneity should not severely affect the ability of gamma delta T cells to respond to foreign antigens, we reasoned that a similar oligoclonal repertoire of alpha beta T cells would lead to a profound impairment of the MHC-restricted response. We used heteroduplex analysis in this research to study the clonal complexity of the peripheral alpha beta T-cell repertoire in human subjects and supply evidence for the presence of alpha beta clonal expansions. Clonal predominance in the alpha beta T-cell repertoire of normal subjects was not simply related to age, since the PBL of young donors also showed clonal expansions and did not always correlate with a numeric increase in the corresponding V beta family. However, the type of alpha beta expansion appears to be strikingly different from the gamma delta expansions. In the case of alpha beta T cells, even in the presence of clonal dominance, evidence for a residual polyclonal background was found in all the donors tested, irrespective of age. The observation that true oligoclonality is exceptionally rare among alpha beta T lymphocytes could mean that maintenance of a highly diversified reservoir of TCR is primary for these cells throughout life.
Lantelme
E
E
Department of Genetics, Biology, and Medical chemistry, University of Turin, Italy.
Granziero
L
L
Angman
L
L
Giachino
C
C
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000595:Amino Acid Sequence; D002455:Cell Division / Q000235:genetics / Q000276:immunology; D002648:Child; D002675:Child, Preschool; D002999:Clone Cells; D005434:Flow Cytometry; D015329:Gene Rearrangement, T-Lymphocyte / Q000276:immunology; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D005810:Multigene Family / Q000276:immunology; D009692:Nucleic Acid Heteroduplexes / Q000276:immunology; D016133:Polymerase Chain Reaction; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000097:blood / Q000235:genetics*; D012680:Sensitivity and Specificity; D013601:T-Lymphocytes / Q000276:immunology*
D009692:Nucleic Acid Heteroduplexes; D016693:Receptors, Antigen, T-Cell, alpha-beta