Binding of macrophages and B lymphocytes mediated by dengue virus antigen and the virus-induced helper cytokine.

Macrophage (M phi) process dengue type 2 virus (DV) antigen and present it to B cells leading to their clonal expansion and transmit DV-specific helper cytokine (HF) signal to B cells. The present study was, therefore, undertaken to investigate the binding of DV or HF-pulsed M phi with 51Cr- labelled B lymphocytes. The binding was dependent on the number of DV antigen positive M phi or dose of HF, period (peak with DV at 24 h and with HF at 4 h) and temperature of incubation. The binding was significantly increased by treating DV-pulsed M phi with DV-specific helper T cells or HF. Glutaraldehyde fixed M phi (which do not process DV antigen (Rizvi et al. 1989)) had poor binding capacity. The binding was DV- or HF-specific as it was inhibited by treatment of M phi with specific antisera. The findings thus show that M phi and B lymphocytes are actively bridged via DV antigen and HF to effectively transmit the antigen-specific signal.