The presence of HIV in SCID MICE with HIV encephalitis correlates with gliosis

Reactive astrocytosis is a characteristic pathologic finding germane to the condition of HIV encephalitis (HIVE) and its quantitation likely provides an index to the severity of CNS infection. A model of HIV encephalitis in severe combined immunodeficient (seid }mice has been developed and offers a unique opportunity to study factors which result in the development of gliosis in this disorder. In this paradigm, seid mice are intracerebrally inoculated with human cells and/or HIV-1 and subsequently sacrificed. We report on reverse transcriptase polymerase chain reaction (PCR) data obtained on 55 separate cases of seid mice injected with HIV and human cells, human cells only, or HIV only. Also, pathologic analysis of seid mouse brain tissues was performed on 30 of these cases and this data was collated against corresponding PCR results. HIV gag, and less frequently nef and tat/rev mRNA was detected in an area of brain remote from the inoculation site in two thirds of cases tested and at sacrifice dates up to 3 months after inoculation of human cells and virus. HIV gag and nef mRNA were also detected in 30% of the HIV only injection cases as late as 18 days after inoculation. The mean astrocyte counts of individual cases were used as a measure of the severity of CNS infection caused by various injection groups. We have shown that positive PCR results, positive p24 results, the presence of macrophages, and the HIV plus cells f H+C) injection group were all predictive of higher mean astrocyte counts in this model.