Maedi-Visna. Etiology and Immune Response. In: Pétursson G, Hoff-jørgensen R, editors. Maedi-Visna and Related Diseases. Boston: Springer US; 1989. pp. 55-74. [DOI: 10.1007/978-1-4613-1613-8_4]

Evaluation of two recombinant Maedi-visna virus proteins for use in an enzyme-linked immunosorbent assay for the detection of serum antibodies to ovine lentiviruses

Defined segments of the gag polyprotein and transmembrane envelope glycoprotein from Maedi-visna virus were expressed as glutathione S-transferase fusion proteins in Escherichia coli and evaluated singly and in combination for use in an enzyme-linked immunosorbent assay (ELISA). Two hundred sixty field serum specimens from 15 sheep flocks were tested in parallel with recombinant and whole-virus antigens, and the relative sensitivities and specificities of the recombinant antigens were calculated. When the recombinant gag and transmembrane proteins were used in combination, a sensitivity of 97.4% and a specificity of 99.4% relative to whole-virus antigen were observed, indicating the utility of these proteins in diagnostic testing.

Comparison of immunoblots with neutralizing and complement fixing antibodies in experimental and natural cases of visna-maedi

In this study the humoral antibody response in visna-maedi virus disease in sheep during long-term infection was analyzed utilizing immunoblot assays, neutralization tests and complement fixation tests. In immunoblot assays antibodies to several virus specific protein bands were detected, both against the viral envelope glycoproteins and internal proteins of the virus. The immunoblot reaction pattern resembled that found in HIV-1 infection in humans, consistent with reported similar molecular weight of the major proteins of these two viruses. The immunoblot band pattern was compared with the pattern of complement fixing and neutralizing antibodies through the preclinical and clinical course in natural and experimental cases of visna-maedi. Of six immunoblot bands identified as virus specific, the antibody response against three gag products and the major env glycoprotein appeared early in infection, at a similar time as the complement fixing antibodies. The response against two proteins, one presumably the transmembrane protein and the other possibly a gag precursor, was delayed.