Using a panel of monoclonal antibodies to detect Maedi virus (MV) in chronic pulmonary distress of sheep

A selected panel of six monoclonal antibodies (mAbs) against Maedi-Visna vi rus (MVV), recognising the core proteins (p27 and p15) and the envelope pro tein (gp105) of MVV, was tested using different unmasking techniques on par affin embedded lung samples of a seropositive sheep. Only three mAbs were c hosen, according to their strong reactivity. mAbs 1A7, 1B6 and 4B3 were emp loyed in an immunohistochemical trial focused on the diagnosis of the lungs of 26 sheep with progressive pulmonary distress. These mAbs demonstrated M VV in 21 out of 26 cases including lymphoid interstitial pneumonia (LIP) an d pulmonary adenomatosis. In only nine cases did all three mAbs react posit ively with the same sample. The sensitivity of immunohistochemical diagnosi s of Maedi pneumonia can be increased by using mAbs 1A7, 4B3 and 1B6 togeth er; that is a panel of mAbs direct against the envelope (gp105) and capsid (p27) viral proteins. The positive signal was focal and confined to the cyt oplasm of bronchoalveolar epithelial cells and alveolar-interstitial macrop hages. The results suggest that this panel of mAbs is useful to confirm sev ere LIP lesions such as Maedi pneumonia, to demonstrate Maedi infections in mild LIP, to demonstrate MVV in mixed pulmonary changes, and to investigat e the pathogenesis of Maedi-Visna. (C) 2000 Elsevier Science B.V. All right s reserved.