Patients suffering from chronic CHIKV disease exhibit circulating CHIKV specific CD4+ T cell responses, primarily targeting viral E1 and nsP1 proteins.71 To assess the local CD4+ T cell response, we isolated joint-associated cells at 28 dpi from uninfected control mice and mice infected with a recombinant CHIKV strain encoding a CD8+ T cell receptor epitope from ovalbumin (OVA).72 Stimulation with overlapping CHIKV E1 peptides triggered responses in CD4+ T cells, confirming antigen specificity (Figure 4H), while CD8+ T cells responded only to the OVA-257 epitope (Figure 4I). Here, CD8A is linked to glycogen storage disease VI.