Differential distribution of WC1(+) gammadelta TCR(+) T lymphocyte subsets within lymphoid tissues of the head and respiratory tract and effects of intranasal M. bovis BCG vaccination.

BCG vaccination of neonatal calves induces significant protection against bovine tuberculosis. The enhanced protection observed in neonatal calves may be linked to an enhanced capacity for IFNgamma production by innate cells, including WC1(+) gammadelta T cells, which constitute a major population in young cattle. Intranasal BCG vaccination of mice induces high levels of IFNgamma in the lungs, which may enhance protection against subsequent challenge with virulent strains of mycobacteria. We used an intranasal BCG vaccination model in calves to study the effect on the distribution of WC1(+) gammadelta T cells expressing two alternate forms of WC1: WC1.1 and WC1.2. These subsets of WC1(+) gammadelta T cells have previously been shown to have a differential capacity for IFNgamma secretion. Our results indicate that there is a selective expansion/recruitment of gammadelta T cells expressing the IFNgamma-associated WC1.1 isoform in tissues of the lungs and upper respiratory tract following intranasal BCG vaccination.