Cytokine responses to various larval stages of equine strongyles and modulatory effects of the adjuvant G3 in vitro

Aims To generate different larval stages ofStrongylus vulgarisand to study cytokine responses in cultures of eqPBMC exposed to defined larval stages ofS. vulgarisand cyathostomins with the aim to understand the early immune reaction to these parasites. Methods and results EqPBMC were exposed toS. vulgarislarvae (L3, exsheated L3 and L4) and cyathostomin L3 and analysed for cytokine gene expression. Procedures for decontamination, culturing and attenuation of larvae were established. Transcription of IL-4, IL-5 and IL-13 was induced by bothS. vulgarisand cyathostomin L3. Moulting ofS. vulgarisfrom L3 to L4 stage was accompanied by a shift to high expression of IL-5 and IL-9 (exsheated L3 and L4) and IFN-gamma (L4 only). In parallel, the adjuvant G3 modified the cytokine profile induced by both parasites by reducing the expression of IL-4, IL-5 and IL-10 while concomitantly enhancing the expression of IFN-gamma. Conclusion The L4 stage ofS. vulgarisgenerated a cytokine profile different from that induced by the earlier L3 stage ofS. vulgarisand cyathostomins. This diversity depending on the life cycle stage will have implications for the choice of antigen and adjuvant in future vaccine design.