CD4 and its role in infection of rabbit cell lines by human immunodeficiency virus type 1.
Human CD4 (HuCD4) is the principal receptor for human immunodeficiency virus type 1 (HIV-1) in human cell infection. Susceptibility of rabbit cell lines to infection with HIV-1 raised questions concerning whether a CD4 homolog serves as HIV-1 receptor on rabbit cells. Sequence comparisons of rabbit CD4 (RbCD4) cloned from a rabbit thymus cDNA library showed that 6 of the 18 residues implicated in HIV-1 binding by CD4 differ between the human and rabbit proteins. No correlation between RbCD4 expression by rabbit cell lines and their ability to support HIV-1 infection was seen. Transfection of RbCD4-negative, HTLV-I-transformed cell lines with HuCD4 significantly enhanced HIV-1 infectivity, suggesting that these lines lack a receptor present on other RbCD4-negative lines that produce high levels of p24 in their native state. Inhibition of HIV-1 infection with soluble HuCD4 was demonstrated for all rabbit lines tested, but complete inhibition was obtained only with a rabbit T-cell line expressing RbCD4 and with HuCD4 transfectants. The results suggest that HIV-1 infection of the RbCD4-positive line proceeds through a receptor similar to HuCD4 but that an additional receptor or receptors may serve this purpose in RbCD4-negative lines.
Hague
B F
BF
Laboratory of Immunogenetics, National Institute of Allergy and Infectious Diseases, National Institutes of Health, Rockville, MD 20852.
Sawasdikosol
S
S
Brown
T J
TJ
Lee
K
K
Recker
D P
DP
Kindt
T J
TJ
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D015704:CD4 Antigens / Q000235:genetics / Q000502:physiology*; D002478:Cells, Cultured; D003001:Cloning, Molecular; D015658:HIV Infections / Q000378:metabolism*; D015497:HIV-1 / Q000254:growth & development*; D066298:In Vitro Techniques; D008969:Molecular Sequence Data; D009838:Oligodeoxyribonucleotides / Q000737:chemistry; D011817:Rabbits; D015728:Receptors, HIV / Q000378:metabolism*; D016415:Sequence Alignment; D013045:Species Specificity
D015704:CD4 Antigens; D009838:Oligodeoxyribonucleotides; D015728:Receptors, HIV