Highly pathogenic avian influenza H5N1 viruses are capable of causing poultry epidemics and human mortality. Vaccines that induce protective neutralizing antibodies can prevent outbreaks and decrease the potential for influenza A pandemics. Identifying unique H5N1 virus-specific HLA class II-restricted epitopes is essential for monitoring cellular strain-specific immunity. Our results indicate that 80% of the 30 study participants who were inoculated with an H5N1 vaccine produced neutralizing antibodies. We used intracellular cytokine staining (ICS) to screen and identify six DR1501-restricted H5N1 virus epitopes: H5HA148-162, H5HA 155-169, H5HA253-267, H5HA260-274, H5HA 267-281 and H5HA309-323. Tetramer staining results confirmed that two immunodominant epitopes were DR1501-restricted: H5HA 155-169 and H5HA267-281. Both are located at the HA surface and are highly conserved in currently circulating H5N1 clades. These results suggest that a combination of ICS and tetramer staining can be used as a T-cell epitope-mapping platform, and the identified epitopes may serve as markers for monitoring vaccine efficacy.
ASJC Scopus subject areas
- Molecular Medicine