CIITA and infection: Furthermore, genes encoding complement pathway factors (C4BP, CFHR5) were significantly up-regulated at 4 hour post infection with E. granulosus. It’s worth noting that CIITA, the major histocompatibility class II (MHCII) transactivator (CIITA), which specifically regulates MHCII expression, manifested a significantly higher expression level in CE infection sheep at four hour post infection (Table 2).