Differences in the interaction of HIV-1 and HIV-2 with CD4.
Inhibition of infectivity, cytopathicity, and binding by soluble CD4 was determined for several human immunodeficiency virus (HIV)-1 and HIV-2 strains. Although infectivity and binding of both groups were blocked equally well by OKT4A, HIV-2 viruses were more refractory to inhibition by soluble CD4. Rates of envelope shedding, as determined by thermal stability, did not differ between HIV-1 and HIV-2; however, Scatchard plot analysis of radiolabeled virus binding revealed that fewer HIV-2 virions were bound to CD4+ cells under saturating conditions. The HIV-2 viruses also possessed consistently greater infectivity, whereas greater concentrations of gp120 were found in supernatants of HIV-1-infected cells and in HIV-2 virus pellets, suggesting that more envelope glycoprotein remains associated with HIV-2 virions. This factor may contribute to the observed in-vitro resistance of HIV-2 viruses to soluble CD4.
Department of Retroviral Research, Walter Reed Army Institute of Research, Rockville, Maryland.
D J
DJ
Looney
S
S
Hayashi
M
M
Nicklas
R R
RR
Redfield
S
S
Broder
F
F
Wong-Staal
H
H
Mitsuya
D000911:Antibodies, Monoclonal; D015703:Antigens, CD / Q000276:immunology; D000945:Antigens, Differentiation, T-Lymphocyte / Q000276:immunology; D001667:Binding, Competitive; D015704:CD4 Antigens / Q000378:metabolism / Q000494:pharmacology*; D016827:CD8 Antigens; D002460:Cell Line; D002498:Centrifugation; D003588:Cytopathogenic Effect, Viral; D016264:Dextran Sulfate; D003911:Dextrans / Q000494:pharmacology; D015699:HIV Envelope Protein gp120 / Q000032:analysis; D015497:HIV-1 / Q000378:metabolism / Q000502:physiology*; D015498:HIV-2 / Q000378:metabolism / Q000502:physiology*; D006801:Humans; D007700:Kinetics; D011994:Recombinant Proteins / Q000494:pharmacology; D012044:Regression Analysis; D015302:Simian Immunodeficiency Virus / Q000502:physiology; D014461:Ultracentrifugation
D000911:Antibodies, Monoclonal; D015703:Antigens, CD; D000945:Antigens, Differentiation, T-Lymphocyte; D015704:CD4 Antigens; D016827:CD8 Antigens; D003911:Dextrans; D015699:HIV Envelope Protein gp120; D011994:Recombinant Proteins; D016264:Dextran Sulfate