Antibody raised against soluble CD4-rgp120 complex recognizes the CD4 moiety and blocks membrane fusion without inhibiting CD4-gp120 binding.
We studied the humoral response of mice immunized with soluble CD4-rgp120 complex, testing polyclonal and monoclonal antibodies (mAbs) with the aim of identifying molecular changes that take place after the first interaction between human immunodeficiency virus and the cell surface. The antisera had a paradoxically high syncytia-blocking titer associated with anti-CD4 specificity, while their capacity to inhibit CD4-gp120 binding was relatively modest. One of the mAbs produced from these responders blocks syncytia formation but does not inhibit CD4 interaction with gp120. Apparently, this mAb interacts with the CD4 moiety of CD4-gp120 complex and prevents a post-binding event necessary for membrane fusion and viral infection.
Institute for Molecular Immunology, Hospital for Joint Disease, New York, New York.
F
F
Celada
C
C
Cambiaggi
J
J
Maccari
S
S
Burastero
T
T
Gregory
E
E
Patzer
J
J
Porter
C
C
McDanal
T
T
Matthews
D000818:Animals; D000906:Antibodies / Q000276:immunology*; D000911:Antibodies, Monoclonal / Q000276:immunology; D000918:Antibody Specificity; D001666:Binding Sites, Antibody; D015704:CD4 Antigens / Q000276:immunology*; D005260:Female; D015699:HIV Envelope Protein gp120 / Q000276:immunology*; D007114:Immunization; D051379:Mice; D008807:Mice, Inbred BALB C; D011994:Recombinant Proteins / Q000276:immunology
D000906:Antibodies; D000911:Antibodies, Monoclonal; D015704:CD4 Antigens; D015699:HIV Envelope Protein gp120; D011994:Recombinant Proteins