CD4 POSITIVE T-CELLS PRODUCE CYTOTOXIC FACTOR IN CASES OF DENGUE HEMORRHAGIC-FEVER

During dengue virus infection of mice and man, an unique cytokine, cyt otoxic factor (CF), is produced which reproduces various pathological lesions in mice that are seen in human cases of dengue fever (DF) and dengue haemorrhagic fever (DHF). The present study was undertaken on 1 5 cases of DF/DHF and 5 normal healthy control individuals to find out the cell responsible for the production of the human cytotoxic factor (hCF), Peripheral blood mononuclear cells (PBMC) or their enriched su bpopulations of monocytes, B- or T-cells were cultured for 24 h and th e culture supernatants were assayed for the presence of hCF by ELISA, dot blot and cytotoxicity assay. The findings showed that hCF was prod uced by T-cells and not by the monocytes or B-cells. Pretreatment of t he T-cells with anti-CD4 antibody abrogated the production of hCF whil e anti-CD8 had no effect. Presence of hCF-specific mRNA was found by N orthern hybridization in the CD4 positive T-cells only of the cases an d not in the CD8 positive T-cells, B-cells or monocytes, thus confirmi ng, for the first time, production of hCF by CD4 positive T-cells.