Protection against bovine leukemia virus infection in sheep by active and passive immunization.

Publisher Website
Google Scholar
Abstract
The protective effect of active and passive immunization against bovine leukemia virus (BLV) infection was tested in sheep. Eight sheep were immunized 3 times at 2-week interval with concentrated BLV antigen treated with Triton X-100. Two weeks after the last immunization, when antibody titers to glycoprotein (gp) (gp antibody) were 32 to 256, 4 of the 8 immunized sheep were challenged with infected sheep blood and remained uninfected. These 8 sheep were challenged or rechallenged when their gp antibody titers fell to 1 to 8, and all animals were infected. Of 10 sheep immunized passively with various doses of immunoglobulin obtained from infected sheep serum, animals that had gp antibody titers of 64 showed protection against challenge inoculation. To sum up the relationship between serum antibody titers and protective effect, all sheep that had gp antibody titers of 64 or more and half the sheep that had titers of 32 showed resistance to infection. Resistance was observed in only one of the 13 sheep that had titers of 16 or less.