Human infection with Ascaris lumbricoides is associated with suppression of the interleukin-2 response to recombinant cholera toxin B subunit following vaccination with the live oral cholera vaccine CVD 103-HgR

To investigate the potential immunomodulatory effects of concurrent ascaria sis on the cytokine response to a live oral vaccine, we measured cytokine r esponses to cholera toxin B subunit (CT-B) following vaccination with the l ive oral cholera vaccine CVD 103-HgR in Ascaris lumbricoides-infected subje cts randomized in a double-blind study to receive two doses of either alben dazole or placebo prior to vaccination and in a group of healthy U.S. contr ols. Postvaccination cytokine responses to CT-B were characterized by trans ient increases in the production of interleukin-2 (IL-2; P = 0.02) and gamm a interferon (IFN-gamma; P = 0.001) in the three study groups combined; how ever, postvaccination increases in IFN-gamma were significant only in the a lbendazole-treated A, lumbricoides infection group (P = 0.008). Postvaccina tion levels of IL-2 were significantly greater in the albendazole-treated g roup compared with the placebo group (P = 0.03), No changes in levels of Th 1 and Th2 cytokines in response to control ascaris antigens were observed o ver the same period, These findings indicate that vaccination with CVD 103- HgR is associated with a Th1 cytokine response (IL-2 and IFN-gamma) to CT-B , that infection with A, lumbricoides diminishes the magnitude of this resp onse, and that albendazole treatment prior to vaccination was able to parti ally reverse the deficit in IL-2, The potential modulation of the immune re sponse to oral vaccines by geohelminth parasites has important implications for the design of vaccination campaigns in geohelminth-endemic areas.