Role of calcium in induction of dengue virus-specific helper T cells.

Dengue type 2 virus (DV) induces the generation of T helper cells (TH) in the mouse spleen. These TH on adoptive transfer to DV primed syngeneic mice enhance the clonal expansion of antigen-specific antibody plaque forming cells. The present study was undertaken to investigate the role of M phi and Ca2+ in the induction of DV-specific TH. The results show that M phi are obligatory for the induction of DV-specific TH. It was observed that DV antigen stimulate the influx of calcium ion (Ca2+) into T cells as shown by radiolabelled (45Ca) and the influx of Ca2+ increases with time of incubation, reaching a maximum level after 1 hr of incubation. The proliferation of T cells was found to be dependent on presence of Ca2+ as it was inhibited by Ca channel blocking drugs and in the absence of Ca in the medium. Thus showing that Ca2+ plays an important role in the induction of DV-specific TH cells.