The AIDS VACCINE 2004 conference today announced the major trends in research that the different research teams throughout the world are pursuing.
The science will be presented during the conference which is taking place in Lausanne until September 1, 2004. The advances in fundamental research, notably through a better understanding of the complex processes of immune defence, HIV and the functioning of vaccines, promote the genesis and development of new vaccine candidates.
Understanding protection correlates
Today, one of the major focuses in HIV research consists in understanding how our immunity is stimulated by a vaccine and how the latter enables our body to defend itself. In technical terms, these are called “protection correlates”. New discoveries have been made in this field and some will be presented at the AIDS VACCINE 2004 conference. While cytotoxic CTL cells (CD8+) are indispensable for killing cells infected by HIV, these cells lose their cytotoxic capacity when the virus replicates continually. They become exhausted. Researchers have recently discovered that certain molecules and cells in our body precede and preserve the eliminating activity of CTLs. For example, T CD4+ lymphocytes secrete interleukin-2 (IL-2), an immune system regulating factor which seems to have a crucial role in controlling the proliferation of HIV.
Renewal in the search for HIV neutralising antibodies
Because HIV mutates so rapidly, and the targets at which antibodies are directed are often hidden or folded in on themselves, research for a “humoral” vaccine has slowed down in recent years. Indeed, researchers have progressively moved away from trying to provoke an immune reaction (humoral) that seeks to produce antibodies that can neutralise the virus, instead pursuing more actively the option of creating so-called cellular immunity. However, recent research has moved current thinking in HIV vaccine research to revisit the idea and clinical studies will be looking at how antibodies can fix themselves on HIV and thus efficiently block its entry into host cells, thereby facilitating its elimination.
Hopes for a “prime boost”
Contrary to classical vaccine boosters, a new strategy is being developed comprising two different “antigen transporters” (vectors). A first dose of antigen A in vector X is administered, followed by a booster using the same antigen A in vector Y this time. In this way, immune reactions to, and the consequent destruction of, the transporter are reduced. The first injection wakes up (“primes”) the immune system, the second “boosts” it. This has been developed since single administration does not seem to offer efficient protection against HIV.