The goal of this project is to supplement light and electron microscopic studies of HIV-infected experimental and human tissues with in situ nucleic acid hybridization techniques and immunocytochemical methods to investigate the distribution of HIV in the CNS and other tissues from patients with AIDS and experimental animals. Our major findings were: 1 ) in transgenic mice, created by J. Leonard, M. Martin (LMM, NIAID) and associates, our in situ hybridization and electron microscope studies showed that HIV-specific nucleotides were present in abnormal keratinocytes found in skin lesions. 2) Affected transgenic mice were small and had retarded CNS development, especially in neuronal populations still migrating postnatally to destinations found in mature animals (i. e. , cerebellar granule cells) . 3) In bone marrow cultures infected with HIV-1 by B. Potts, electron microscope and in situ hybridization studies showed that HIV-specific nucleotides were localized in cells of the promonocyte/macrophage lineage.