OBJECTIVETo study cellular and humoral immune responses to NS1 protein in mice inoculated intramuscularly with recombinant plasmid expressing dengue 2 NS1 gene.

METHODSThe eukaryotic expressing plasmid pCNX2-NS1 was injected into tibialis anterior muscle in mice. The mice were subsequently boosted with the same dose and same method twice after the initial inoculation. The mice were killed at four-week intervals and their serum and spleen cells were harvested for further test.

RESULTSDengue 2 antibodies were detectable in the sera from inoculated animals four weeks after the last boost. The changes of CD4+ T lymphocyte and CD8+ T lymphocyte were also determined by flow cytometry.

CONCLUSIONThe recombinant plasmid containing dengue 2 NS1 genes is immunogenic in intramuscularly inoculated mice. The vaccinated mice produced dengue-2 specific and long lasting immunity.