Differential response of human naive and memory/effector T cells to dendritic cells infected by respiratory syncytial virus

Summary In vitro studies have contributed substantially to the understanding of immunopathology of respiratory syncytial virus (RSV)‐mediated disease. In the present study we compared the effect of RSV‐infected dendritic cells on the time–course of the primary and memory/effector T cell response in vitro . Cultures with uninfected dendritic cells known to elicit T helper 2 (Th2) responses and with polyinosinic‐polycytidylic acid (poly‐IC)‐stimulated dendritic cells known to elicit Th1 responses served as controls. At day 1 after stimulation there was a high proportion of interleukin (IL)‐2 and tumour necrosis factor (TNF)‐α‐producing T cells with no difference in number of producing T cells as well as concentration of secreted cytokines between RSV‐infected and control cultures. However, up to day 3 generation of IFN‐γ was reduced markedly. In addition, there was a reduced proliferation in RSV cultures. At day 7 the RSV‐treated cultures showed a preponderance of IL‐4 generation. At days 21–24, after three rounds of restimulation, memory/effector T cells matured under the influence of RSV were still not fully polarized but in contrast to the primary response displayed a predominance of Th1 cytokines. Contact with RSV‐infected HEp‐2 cells inhibited proliferation of T cells; memory effector T cells were less sensitive to contact inhibition than naive T cells. In addition, RSV inhibited the stimulated rearrangement of cortical actin more effectively in naive compared to memory T cells. In summary, we have shown that RSV infection of dendritic cells has a distinct modulatory effect on the primary response and a less pronounced effect on the memory response.