Passive protection against bovine rotavirus-induced diarrhea in murine model by specific immunoglobulins from chicken egg yolk.

Chicken egg yolk immunoglobulins (yIg) specific against bovine rotavirus (BRV) serotypes 6 (strain Shimane) and 10 (strain KK-3) were used for oral passive immunization of suckling mice against experimental BRV challenge. The protective capacity of the antibody preparation was tested using different concentrations of yIg against a challenge dose of 10(7.5) TCID50 for Shimane and 10(7.0) TCID50 for KK-3 strain. There was a significant homotypic (P < 0.05) and heterotypic (P < 0.01) protection using 160 anti-Shimane or 160 anti-KK-3 neutralizing antibody titer (NAT) compared to control mice given yIg derived from eggs of mock-immunized (control) hens. The titer of infectious BRV recovered from intestinal tissue or luminal chyme decreased with increasing homotypic yIg NAT. A decrease in degree and duration of BRV antigen localization in the villus epithelial lining was observed in mice treated with homotypic yIg at optimum dose for prevention of diarrhea. The NAT in sera of challenged mice increased with decreasing NAT in the yIg given before challenge suggesting that protection was dose-dependent. The present findings indicate that a passive protection could be achieved by the use of yIg against BRV-induced diarrhea in this murine model.