Functional properties of Salmonella minnesota Rb-bound and Rb-unbound cell fractions in elderly donors.

The capacity of Salmonella minnesota R345 (Rb) binding to human peripheral blood lymphocytes allows the recovery of Rb-bound and Rb-unbound cell populations that elicit different functions. Here, we have applied this method to lymphocytes from aged individuals to evaluate the possibility that such an approach could reverse the senescence-related impaired immune responsiveness. In this regard we show that Rb binding augments either spontaneous or T-dependent plaque-forming cell generation in Rb-unbound fraction. By contrast, Rb-bound cells are enriched for lymphocytes releasing several lymphokines. This experimental approach seems to represent a useful tool to elucidate better the age-related alterations of the immune function.