RABIES VIRUSES INFECT PRIMARY CULTURES OF MURINE, FELINE, AND HUMAN MICROGLIA AND ASTROCYTES

Recent studies have reported the detection of rabies viral antigens an d virions in astrocytes and microglia of rabies-infected animals. As a first step toward understanding whether these glial cells may be invo lved in rabies virus replication, persistence, and/or pathogenesis, we explored their potential to be infected in vitro. Primary cultures of murine, feline, and human microglia and astrocytes were infected with several different rabies viruses: two unpassaged street virus isolate s, a cell culture-adapted strain, and a mouse brain-passaged strain. I nfection, as determined by immunofluorescence, was detected in 15 of t he 16 (94%) virus-glial cell combinations. Replication of infectious v irus, determined by infectivity assay, was detected in 7 of the 8 (88% ) virus-cell combinations. These results show that astrocytes and micr oglia can be infected by rabies viruses, suggesting that they may have a potential role in disease, perhaps contributing to viral spread, pe rsistence and/or neuronal dysfunction.