Functional Characterization in Vitro of Two Human T-cell Subpopuiations with Different Affinities to Sheep Erythrocytes

Publisher Website
Google Scholar
Abstract
On the basis of their different abilities to form rosettes with unsensitized sheep erythrocytes (SRBC), two subpopuiations of human T lymphocytes were separated by the rosette sedi-mentation technique. In a series of in vitro experiments the T cells carrying high-avidity receptors for SRBC (‘active’ T cells) were shown to respond significantly better when stimulated with purified protein derivative (PPD) and allogeneic cells than the subpopulation carrying low-avidity reecplors ‘non-active’ T cells). On the other hand, the latter responded better to phytohaemaggiutinin, concanavalin A and pokcweed mitogen; it was likewise demonstrated that these cells were better stimulators in a mixed lymphocyte reaction. The role of monocytcs in mitogen and PPD responses was investigated by adding such cells to Fe-treated suspensions. These were found io be crucial for an optimal response of both subpopuiations. Furthermore, ditfereni patterns of activation were observed for the active and non-active cells. Especially interesting was the observation that the Con A response of the active fraction was more mono-cyte-dependent than that of the non-active one.