Hmmnnn..CD4 binding sites bind to CD4, a necessary component, (T-cell surface receptor for antigens), of immune responses. If this antibody is introduced to a patient, to what extent will the introduced antibody become competitive against endogenous CD4 function?? If competition is high enough, couldn't this then just lead to the same level of immune compromisation as occurring after the HIV virus has done it's dirty deed? There needs to be considerable specificty if this is going to work, ensuring that the patients immune system can function properly, otherwise, this just defeats the object!!