There are two different approaches to designing an AIDS vaccine. One focuses on spurring the body to make armies of killer T cells — the 'foot soldiers' of our cell-based immune response — that track down and destroy cells that have been infiltrated by a viral invader.
The other stimulates the production of antibodies, which can in theory lock onto viruses in the bloodstream and prevent them from infecting their target cells.
In this article, Erika Check explores the pitfalls and advantages of both approaches and reports that ultimately, many vaccine developers believe that success may come from a combination of vaccines that stimulate both cellular immunity and the production of antibodies.
Reference: Nature 423, 912 (2003)