Gene Transcription Profile in Mice Vaccinated with Ultraviolet‐attenuated Cercariae of Schistosoma japonicum Reveals Molecules Contributing to Elevated IFN‐γ Levels

Vaccination with ultraviolet‐attenuated cercariae of Schistosoma japonicum induced protective immunity against challenge infection in experimental animal models. Our preliminary study on the transcription levels of IFN‐γ and IL‐4 in splenic CD4+ T cells revealed that attenuated cercariae elicited predominantly a Th1 response in mice at the early stage, whereas normal cercariae stimulated primarily Independent responses. Further analysis on the gene profile of the skin‐draining lymph nodes demonstrated that the levels of IFN‐γ were significantly higher in vaccinated mice than those in infected mice at day 4, 7 and 14 post‐vaccination or post‐infection. However, for IL‐12 and IL‐4, the potent inducers of Th1 and Th2 responses, respectively, as well as IL‐10, there were no differences over the course of the experiment between the infected and vaccinated mice. To explore the underlying factors that may potentially contribute to elevated IFN‐γ in vaccinated mice, the mRNA profiles of the skin‐draining lymph nodes at day 4 post‐exposure were compared using oligonucleotide microarrays. Within the 847 probe sets with increased signal values, we focused on chemokines, cytokines and relevant receptors, which were validated by semi‐quantitative RT‐PCR. A comprehensive understanding of the immune mechanisms of attenuated cercariae‐induced protection may contribute to developing efficient vaccination strategies against S. japonicum, especially during the early stage of infection. Edited by: Zu‐Xun GONG