BIPHASIC IMMUNE-RESPONSES OF CATS UNDER CONTROLLED INFECTION WITH A FELINE ENTERIC CORONAVIRUS-79-1683 STRAIN

Kittens inoculated orally with 10(2) PFU of feline enteric coronavirus developed no antibody to the virus despite the repeated challenges. H owever, they developed antibody for a long period with 5 x 10(3) - 1.6 x 10(5) (mean 3 x 10(4)) and with 2.5 x 10(3) - 2 x 10(4) (mean 6 x 1 0(3)) immunoperoxidase antibody titer when they were challenged with 1 0(5) and 10(3) PFU of virus following previous challenges, respectivel y. Viremia was found when kittens were inoculated with 10(5) PFU of vi rus, but not with 10(3) PFU of virus. The dose of 10(3) PFU of virus s eemed to be a lower limit to establish infection. These results indica te that local infection induces a low antibody response and systemic i nfection induces a high antibody response.