RABBIT HEMORRHAGIC-DISEASE VIRUS (RHDV) - ULTRASTRUCTURE AND BIOCHEMICAL-STUDIES OF TYPICAL AND CORE-LIKE PARTICLES PRESENT IN LIVER HOMOGENATES

Calicivirus particles isolated from rabbits suffering from acute RHD w ere compared with virions found in rabbits with chronic disease. Liver homogenates of rabbits with the protracted disease display no hemaggl utinating activity and contain viral particles with diameters of 25-27 nm. These virions contain only one structural protein of 30 kDa and a re distinctly smaller than intact rabbit hemorrhagic disease virus (RH DV) (32-40 ma). To prove the RHDV identity of the smaller virions, the ir reactivity with RHDV specific antibodies was investigated by immuno blots of the virion protein and by immunoelectron microscopy. Proteoly tic digestion of RHDV particles with alpha-chymotrypsin did not transf orm RHDV into the smaller form. We assume that these core-like particl es (CLPs) are not a result of proteolytic digestion but arise from a t runcated RHDV genome or defective expression.