Infection of mouse brain by HIV‐1

We performed virological and neuropathological studies of the brains of mice that had been infected with chimeric HIV‐1, constructed by replacing the gp120 coding region with gp80 of ecotropic murine leukemia retrovirus. Mice were inoculated at varying ages, ranging from pups of 2 weeks age to more mature mice of three months age. Several modes of virus inoculation were investigated including intravenous, intraperitoneal and intranasal. Animals were investigated for the presence of virus at several time points post infection (p.i.). In addition to standard inbred strains, mice deficient in acquired or innate immunity were utilized. At necropsy, brains were cut in half sagittally, with one half used for virus identification by QPCR and p24 ELISA. The other half was fixed in formalin and embedded in paraffin for standard histopathological evaluation and immunohistochemistry. Viral sequences were detected in brain at early or later time points p.i., in part depending on the age of the mouse at the time of infection and on the immune status of the animal. Neuropathological lesions were infrequent, with the most obvious lesions demonstrating focal necrosis. This mouse model of HIV‐1 infection is useful for the study of the timing and control of virus infection of the brain. Supported by NIDA R01‐DA 017618.