One HIV Vaccine Trial Provided Some Small Measure of Hope

Multiple Choice

One HIV vaccine trial provided some small measure of hope for the development of an effective HIV vaccine. This vaccine, known as RV144, was administered to a high risk population in Thailand, and reduced new infections by ~30%. To address the mechanism of immune protection correlating with vaccine efficacy, a series of studies were performed. In one study, total IgG antibodies from four non-infected vaccinees were isolated and were mixed with HIV-infected cells plus peripheral blood lymphocytes from healthy unrelated donors. As a control, IgG antibodies were purified from four donors receiving the placebo, rather than the RV144 vaccine. Six hours later, lysis of the HIV-infected target cells was assessed, as shown in Figure Q40) . Figure Q40) The immune mechanism that correlates with protection based on these data is:

A) CD8-dependent target cell lysis
B) Complement-dependent cell lysis
C) Induction of apoptosis by TNF-R stimulation
D) Target cell apoptosis induced by Fas-ligand stimulation
E) ADCC induced by NK cells