Antibody-mediated Enhancement of Rabies Virus Infection in a Mouse Macrophage Cell Line (P388D1)

The suggestion that antibodies might enhance rabies virus infection of macrophages through opsonization of immune complexes was tested in vitro by adaptation of the rapid fluorescent focus inhibition technique for the examination of a macrophage c ll line (P388D1). Some enhancement of rabies virus infection was shown. The relationship between such enhancement with the 'early death ' phenomenon and its occurrence in vivo is discussed. The precise way in which rabies vaccine confers protection against disease, and the pathogenesis of rabies virus infection are not fully understood. There are occasional failures even when vaccines of established potency have have used. In both monkeys and mice immunized with rabies vaccine and subsequently challenged with rabies virus, some die sooner than non-vaccinated controls given the same challenge (Sikes et al., 1971; Blancou et al., 1980). The mechanism underlying this 'early death ' phenomenon is obscure, but it appears to be mediated by antibody, rather than by cell-mediated immune processes (Prabhakar & Nathanson, 1981). It has been suggested (Porterfield, 1981) that antibodies might enhance rabies virus infection of macrophages through their opsonization of immune complexes in