Isolation and quantitation of HIV in peripheral blood.

Quantitation of replication-competent human immunodeficiency virus (HIV) in peripheral blood of infected individuals is critical for investigations of HIV pathogenesis and therapy. In this unit, the basic protocol determines the HIV titer in seropositive blood by measuring the tissue culture infectious dose (TCID) by an end-point dilution method. A second basic protocol utilizes the PHA-stimulated T cell blasts (activated T cells) in co-culture with PBMC as described in the first basic protocol for the short-term growth of HIV in vitro. An Alternate Protocol describes the accumulative method of determining 50% tissue culture infectious dose (TCID(50)) of HIV using the Reed-Muench equation when multiple replicates of a given sample are employed in the assay. A consequence of HIV infection is the depletion of CD4(+) target cells, evidenced by syncytia formation or single-cell death; two support protocols detail the evaluation of these cytopathic effects.