NEW YORK (Reuters Health) - An allele-associated sequence variation within the flanking region of cytotoxic T lymphocyte (CTL) epitopes can prevent HIV detection by the immune system, researchers report in the April 5th issue of the Journal of Experimental Medicine.
As senior investigator Dr. Philip J. R. Goulder told Reuters Health, “this study shows that HIV can evade the immune response via an additional mechanism to that which has been best described to date.”
“The best characterized method of HIV ‘escape’,” he noted, “is by variation--mutation--within the fragments of viral proteins--epitopes--that are presented on the surface of the infected cell for recognition by the host immune cells.”
However, in a study involving specimens from HLA-57+ HIV infected patients, Dr. Goulder of the University of Oxford, UK and colleagues found mutations that interfered with antigen processing by a different means. Variant virus-infected cells were not well seen in cytotoxicity assays or in viral inhibition assays in vitro.
This study, he continued, “demonstrated that mutations in regions flanking but outside the epitopes, may prevent the epitopes from ever reaching the cell surface. Thus, this is potent mechanism by which the virus can evade the immune response.”
“Construction of vaccines,” he concluded, “needs to take into account this fact that protein sequences outside particular epitopes may critically affect the presentation of the epitopes.”
Source: J Exp Med 2004;199:1-11. [ Google search on this article ]
MeSH Headings:Epitopes, T-LymphocyteCopyright © 2002 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
