CD4 and infection: Immunological analysis suggested that CD4+ T cells might be an integral component of the immune response and might associate with worm development in yellow cattle and Th1 dominated the immune response during early infection, then the response shifted to Th2-type polarized immunity at 6-7 weeks, but no obvious shift of Th1-type to Th2-type polarized immunity was observed in schistosome-infected water buffalo.