Analysis and PCR detection of antigen compositions of ovine progressive pneumonia virus.

Abstract

Ovine progressive pneumonia virus (OPPV) was proliferated utilizing sheep foetal lung cells, and the cytopathic effect (CPE) of the virus was investigated. OPPV was purified with a 10%-sucrose cushion and then with 20%-55% discontinuous sucrose density gradient centrifugation. The structural proteins and antigen compositions of OPPV were analysed by SDS-PAGE and Western blotting. Besides, the OPP proviral cDNAs of the virus-infected cell cultures and the peripheral blood monocytes from sheep infected by the virus were detected using polymerase chain reaction (PCR). The results show that the CPE of sheep foetal lung cells infected by OPPV is typical of the disease. The purified virions are intact and of high purity when observed with an electron microscope. OPPV proteins consist of 18 polypeptide bands and the molecular weights range from 18 to 120 kd. Among these, 3 were glycoproteins (designated by gp120, gp50 and gp47). The appearance and peak time of the p28 antibody from sheep inoculated with OPPV are earlier than those of the p94 antibody to OPPV. Besides, the strength of immune reaction of p28 antibody is greater than that of p94 antibody. With PCR, it is demonstrated that the initial time for OPP proviral cDNAs to be integrated into the sheep foetal lung cells and the peripheral blood monocytes in sheep were 24 h and 9 d after inoculation, respectively.