PASSIVE-IMMUNIZATION AGAINST SOMATOSTATIN INCREASES RESISTANCE TO EIMERIA-VERMIFORMIS INFECTION IN SUSCEPTIBLE MICE

The effect of in vivo immunoneutralization of somatostatin (SRIF) on E imeria vermiformis intestinal infection was studied in resistant (BALB /c), and susceptible (C57BL/6) mouse strains. An anti-SRIF monoclonal antibody (MAb-SRIF) was used to passively immunize the mice by intrape ritoneal injection. The animals were subsequently orally infected with oocysts of E. vermiformis. Individual fecal samples were collected da ily for 21 days to monitor the kinetics of oocyst shedding. The fecal oocyst shedding was significantly higher in the C57BL/6 strain than in the BALB/c strain (P < 0.01). Passive immunization with MAb-SRIF in t he C57BL/6 mice significantly reduced the number of oocysts in feces ( P < 0.05), when compared to the infected non-immunized mice of the sam e strain. Infected BALB/c mice showed no difference in oocyst shedding in response to the passive immunoneutralization with MAb-SRIF. In con clusion, passive immunization with MAb-SRIF increased resistance to E. vermiformis infection in the susceptible C57BL/6 mice, but not in the resistant BALB/c mice. This suggests that SRIF modulates gut immune f unction in parasitic infection.