CAPRINE ARTHRITIS-ENCEPHALITIS LENTIVIRUS (CAEV) CHALLENGE OF GOATS IMMUNIZED WITH RECOMBINANT VACCINIA VIRUS EXPRESSING CAEV SURFACE AND TRANSMEMBRANE ENVELOPE GLYCOPROTEINS

This study evaluated infection and disease following caprine arthritis -encephalitis lentivirus (CAEV) challenge of goats with existent immun e response to CAEV surface and transmembrane envelope glycoproteins. S ix Saanen goats were vaccinated three times with recombinant vaccinia virus rWR63 expressing glycoproteins encoded by the CAEV-63 envelope g ene. Two goats were immunized with rWRSC11, a control vaccinia virus d erived from the pSC11 vaccinia expression plasmid without the CAEV env elope gene. One pair of rWR63 vaccinated goats received a booster immu nization with recombinant surface glycoprotein in Freund's complete ad juvant, a second pair was boosted by intravenous inoculation with rWR6 3, and the third pair was boosted by immunization with HPLC purified n ative CAEV surface glycoprotein in Freund's complete adjuvant. All six goats vaccinated with rWR63 developed antibody responses to CAEV enve lope glycoproteins; however, CAEV-63 neutralizing antibody was not det ected. Neither of the rWRSC11-vaccinated goats developed CAEV reactive antibody. All goats were challenged by intravenous inoculation with 1 0(6) TCID50 CAEV-63. All goats became infected following challenge inf ection, shown by detection of serum antibody to CAEV core proteins and virus isolation. Existent CAEV-63 immune responses did not detectably alter the severity of inflammatory joint lesions at 24 weeks postchal lenge.