More information has emerged about the role of CD8 cells in preventing HIV disease progression. A study published today in Nature Immunology found that the CD8 cells of HIV non-progressors were better at reproducing themselves and are also able to produce an HIV inhibiting molecule. This is the second recently published study suggesting an important role for CD8 cells in long-term immune control of HIV.
A team of investigators in the US and Netherlands closely monitored the immune systems of 40 people, fifteen of whom were non-progressors and had remained well despite chronic HIV infection and without the use of antiretroviral drugs for up to 20 years.
Analyses showed that there was no difference in the absolute number of CD8 cells between the non-progressors and those with evidence of immune damage and HIV disease. However, the investigators discovered that the CD8 cells of non-progressors could divide and proliferate more readily when called upon to fight infection. In addition, they also produced higher levels of a molecule called perforin which assists in the destruction of HIV-infected cells.
It is now hoped to use the discovery in both preventative and therapeutic HIV vaccine research, particularly as many potential vaccines attempt to induce a strong CD8 response.
This is the second study in the space of a month to show the importance of CD8 cells to the ability of HIV non-progressors to mount an effective immune response and control the virus. Investigators at the Aaron Diamond AIDS Research Center found that the proteins alpha-defensin 1, 2 & 3 played an important part in the CD8 response of non-progressors. To read the story click here.
Migueles SA et al. HIV-specific CD8+ T cell proliferation is coupled to perforin expression and is maintained in nonprogressors. Nature Immunology (published online, October 7 2002).