GENETIC AND ANTIGENIC CHARACTERIZATION OF CAEV (CAPRINE ARTHRITIS-ENCEPHALITIS VIRUS) RECOMBINANT TRANSMEMBRANE PROTEIN

The env gene fragment of an Italian strain of Caprine Arthritis Enceph alitis virus (CAEV) coding for the hydrophilic region of transmembrane protein was amplified, cloned and expressed in prokaryotic system as fusion protein with glutathione-S-transferase. Sequence analysis revea led 63 to 66% amino acid homology, when compared with three ovine lent iviruses and 83% when compared with one caprine lentivirus. The recomb inant transmembrane protein was efficiently expressed, purified under denaturing conditions and used as antigen in western blotting and ELIS A. Sera from clinically diseased goats strongly reacted in western blo tting and naturally infected animals seroconverted between 20 and 33 w eeks of age. An indirect ELISA performed with this antigen showed impr oved sensitivity in comparison with agar gel immunodiffusion test. Our results confirm that transmembrane protein is an important immunologi cal marker in CAEV infection and its use as antigen may enhance the va lidity of serological diagnosis of Caprine Arthritis Encephalitis.