Purified preparations of SP-PG, a bacterial cell wall sulfated polysaccharide-peptidoglycan, show even better in vivo activity than crude preparations in inhibiting angiogenic lesions induced in nude mice by cultured Kaposi's sarcoma (KS)-derived cells. Apolipoprotein E is another promising compound for the therapy of KS. The percentage of spindle cells in peripheral blood mononuclear cell cultures correlates well with the risk for human immunodeficiency virus type 1-infected individuals to develop KS. Immunodeficient mice that have been inoculated with CD1+ Sup-T1 cells infected with human T cell leukemia/lymphotropic virus type I (HTLV-I) derived from spontaneous T-cell colonies from patients with HTLV-I- associated neurological disease or with conditioned medium of those cells develop a neurological pathology similar to that seen in human patients. The mechanism is likely to be indirect, since no HTLV-I has been recovered from the injected mice. Human herpesvirus (HHV)-6 can infect cervical epithelial cell lines. HHV- 6, but no HHV-7 sequences, have been detected in primary cervical carcinoma samples. No HHV-7 sequences were detected by Southern blot hybridization in Hodgkin's and non-Hodgkin's lymphoma samples. To date, approximately one-half of the genome of HHV7 has been cloned. HHV-7 can reproducibly be propagated in the Sup-T1 cell line, provided that hydrocortisone is added to the culture medium.