( reased attention to the role that T cel...)The quest for an effective HIV vaccine presents new possibilities, challenges

reased attention to the role that T cells could play in an HIV vaccine by spurring cellular immunity. Numerous animal and human studies have confirmed how important cellular immunity is in the early and later stages of HIV infection, even though the virus is never completely eliminated. Vaccines that induce strong cellular immune responses may have some benefits, say the authors. In non-human primate models of HIV infection, T-cell vaccines have reportedly decreased the total amount of virus produced during early infection, caused a reduction in virus levels following the acute stage of infection, or produced some combination of these effects. In many of these animals, disease progression was also delayed.

Based on the scientific evidence, several questions remain, say Drs. Johnston and Fauci: Can a vaccine that does not prevent HIV infection but reduces virus levels and preserves a segment of uninfected CD4+ T cells from destruction benefit the immunized individual" Might people immunized with T-cell vaccines before HIV exposure remain disease-free for a prolonged period once they are infected"

Additionally, T-cell vaccines may reduce secondary HIV transmission if they can help the immune system keep viral replication at a very low level for a long time. Studies have suggested that people with high levels of virus--namely those in the early and late stages of infection--are most likely to infect their sexual partners. A preventive vaccine given before exposure to HIV might stifle the initial burst of virus, better control virus levels and potentially reduce that person’s ability to infect other people, Drs. Johnston and Fauci assert.

Vaccines of this type present several complications, however. T-cell-mediated control of HIV infection may not stave off disease forever. Additional human studies would be needed to determine if the vaccine also reduces the spread of HIV. Finally, an HIV vaccine that delays but does not completely preve
'"/>

Source:NIH/National Institute of Allergy and Infectious Diseases

Page: 1 2 3 4
Related biology news :

1. Association of herpesvirus with lung disorder questioned
2. Research advances quest for HIV-1 vaccine
3. New research questions basic tenet of neuron function
4. Double triumph in stem cell quest
5. Climate change will affect carbon sequestration in oceans, model shows
6. Amazon trees much older than assumed, raising questions on global climate impact of region
7. New evidence questions the simple link between prion proteins and madcow disease
8. Mute swan population helps explain longstanding evolutionary question
9. One big biology question solved
10. Tests may help answer questions about GMOs and allergies
11. Soil nutrition affects carbon sequestration in forests