Table 1.

MECHANISMS OF HIV-PROTECTION BY ANTI-CD4 ANTIBODIES

1) interference with gp120 binding
Antibody	Binding site	Binding to CD4-gp120 complex	Characteristics
OKT4a[76]	First CD4 domain	Does not occur due to epitope masking	Difficult to generate in vivo Immune suppressive
2) interference with the sequence of conformational modifications subsequent to gp120 binding and permissive to coreceptor binding and membrane fusion
Antibody	Binding site	Binding to CD4-gp120 complex	Characteristics
Ibalizumab[46]	Second CD4 domain	Equivalent binding to free and complexed CD4	Non immune suppressive
DB-81[59,60]	Second CD4 domain	Increased binding to complexed CD4	a) Non immune suppressive; b) Fine specificity shared by ESN individuals