Long-lasting changes in the T-cell receptor V beta repertoires of CD4 memory T-cell populations in the peripheral blood of radiation-exposed people

Kusunoki Y, Yamaoka M, Kasagi F, Hayashi T, MacPhee DG, Kyoizumi S
Br J Haematol 122(6):975-84, 2003

Summary

To study the long-term effects of radiation-induced T-cell depletion on the T-cell receptor (TCR) V beta repertoires of human peripheral CD4 T-cell populations, we measured the percentages of CD4 T cells representing each of the full range of possible TCR V beta families in a cohort of atomic bomb survivors. We then estimated the extent to which the expression levels for individual TCR V beta families differed from the average expression level for that particular TCR V beta family across the entire cohort. We found no evidence of a systematic change in the TCR V beta repertoires of the naive CD4 T-cell populations, but memory CD4 T-cell TCR V beta family expression levels diverged significantly from the population average for counterpart families, especially in individuals who had been exposed to higher doses and were at least 20 years of age at the time of the bombing. Comparisons of the TCR V beta family expression profiles in the naive and memory CD4 T-cell pools of the same group of adult survivors revealed that differences in the TCR V beta repertoires of these two types of CD4 T-cell pool were larger in more heavily exposed survivors than in unexposed controls. These findings suggest that the memory CD4 T-cell pools of individuals who received significant radiation doses in adulthood may well have become (and could still be) dependent upon a much less diverse complement of TCR V beta families than would otherwise have been the case.