In a human lymphomyeloid progenitor cell line (KG-1) HIV-1 gp120 binds to chemokine-receptors CXC-R4 and CCR5, only in the presence of CD4.
A CD34+ human hematopoietic progenitor cell lines, KG-1, became susceptible to HIV-1 infection in the presence of a concurrent infection by human herpesvirus-6 (HHV-6). We have now analyzed the possible mechanism(s) underlying this phenomenon, in the light of the recent demonstration that at least two members of the chemokine receptor family, CXCR4 (LESTR/fusin) and CCR5 molecules, are the HIV-1-specific co-receptors, necessary, together with the high affinity receptor CD4, for the entry into target cells of HIV-1. Cytofluorimetric analysis demonstrated that in KG-1 cells, after HHV-6 infection, more than 40% of cell population became CD4 positive and only in KG-1 cells expressing the CD4+ phenotype, the exposure to r-gp120 masks a significant amount, not only of CD4, but also of both CXCR4 and CCR5 chemokine receptors. In fact, only when pre-infected by HHV-6, KG-1 cells, after exposure to r-gp120, exhibit a significant reduction in the percentage of CXCR4 or CCR5-positive cells.
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Department of Clinical and Experimental Medicine, University of Bologna, St. Orsola General Hospital, Italy.
Vignoli
M
M
Furlini
G
G
Ramazzotti
E
E
Maldini
C
C
La Placa
M
M
D015704:CD4 Antigens / Q000378:metabolism; D002460:Cell Line; D015699:HIV Envelope Protein gp120 / Q000378:metabolism*; D015658:HIV Infections / Q000821:virology; D015497:HIV-1 / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000821:virology*; D015654:Herpesvirus 6, Human / Q000502:physiology; D006801:Humans; D019713:Receptors, CCR5 / Q000378:metabolism*; D019718:Receptors, CXCR4 / Q000378:metabolism*
D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D019713:Receptors, CCR5; D019718:Receptors, CXCR4