CD4+ T cell-mediated HLA class II cross-restriction in HIV controllers.

Rare individuals, termed HIV controllers, spontaneously control HIV infection by mounting efficient T cell responses against the virus. Protective CD4+ T cell responses from HIV controllers involve high-affinity public T cell receptors (TCRs) recognizing an immunodominant capsid epitope (Gag293) presented by a remarkably broad array of human leukocyte antigen (HLA) class II molecules. Here, we determine the structures of a prototypical public TCR bound to HLA-DR1, HLA-DR11, and HLA-DR15 molecules presenting the Gag293 epitope. TCR recognition was driven by contacts with the Gag293 epitope, a feature that underpinned the extensive HLA cross-restriction. These high-affinity TCRs promoted mature immunological synapse formation and cytotoxic capacity in both CD4+ and CD8+ T cells. The public TCRs suppressed HIV replication in multiple genetic backgrounds ex vivo, emphasizing the functional advantage conferred by broad HLA class II cross-restriction.

Misidentification of recombinant hepatitis C virus leading to treatment failure with direct acting antivirals.

The use of new Direct Acting Antivirals, specific of HCV, has greatly improved the HCV treatment. Most of the DAA are specific of HCV genotypes. Genotyping methods may target different regions of the HCV genome, though only the whole genome sequencing could confirm the correct genotype. The present study describes the virological investigation of a treatment failure due to the false identification of an unusual 2k/1b recombinant HCV form. It describes the sequencing methods, and the similarity analysis of the sequences to different genotype query sequences, to identify the recombination breakpoint.