IN-VITRO INFECTION OF PRIMARY AND RETROVIRUS-INFECTED HUMAN-LEUKOCYTES BY HUMAN FOAMY VIRUS

The infectivity of human foamy virus (HFV) was examined in primary and cultured human leukocytes; Cell-free infectious viral stocks of HFV w ere prepared from the human kidney cell line 293 transfected with an i nfectious molecular clone of HFV. HFV productively infects a variety o f human myeloid and lymphoid cell lines. In addition, primary cell cul tures enriched for human CD4(+), monocytes and brain-derived microglia l cells, were readily infected by HFV. Interestingly, while infected p rimary CD4(+) lymphocytes and microglial cells showed marked cytopatho logy characteristic of foamy virus, HFV-infected monocyte-derived macr ophages failed to show any cytopathology. In addition, marked cytotoxi city due to HFV infection was seen in both human T-cell leukemia virus type 1- and human immunodeficiency virus type 1-infected T-cell lines and in human immunodeficiency virus type I-infected monocytoid cell l ines. Thus, HFV infection produces differential cytopathology in a wid e host range of primary human leukocytes and hematopoietic cell lines.