Researchers reporting in the JCI were studying cases where HLA-B27 was expressed, which is known to offer protection.
A team of scientists have explained how the expression of protein HLA-B27 offers safety against HCV. It forces the virus to mutate often, creating a less-fit virus in each successive mutated form, they explain.
Protection has been previously linked to CD8+ T cells that recognize HLA-B27 bound to a defined fragment of the viral protein RdRp. The investigators found that to avoid the CD8+ T-cell immune response, HCV accumulates additional compensatory clustered mutations within the immune-dominant epitope.
The research team analyzed HCV isolated from individuals who expressed HLA-B27 but were chronically infected with HCV. In these patients, the HCV escaped the CD8+ T-cell immune response by mutating several parts of the RdRp fragment of interest.
Since each mutation affected the part of the fragment recognized by the CD8+ T cells, the scientists concluded that HLA-B27 provides efficient protection against HCV, because if the virus is to escape recognition by the CD8+ T-cell immune response, it must mutate the RdRp fragment several times.
The study, conducted by investigators from the University of Freiburg and the University of Heidelberg, appears online January 12 in the Journal of Clinical Investigation.