* Did you dialyze the lysate to get rid of the detergent?
* What kind of plates are you using?
* Is your "anti-HIV antibody" polyclonal? Monoclonal? Epitope of interest?
Point being, you could coat the plate with an antibody (that sees an
epitope other than the one(s) recognized by your anti-HIV antibody) in
order to capture the molecule of interest from the lysate.