Figure 4.
CD4 T cell recognition of ZIKV peptide NS1 81–100 is restricted by two distinct HLA alleles. APC expressing defined HLA class II heterodimers or non-expressing parental cells DAP.3 or RM3 (at left) were incubated with 20-mer peptide NS 81–100, washed, and co-cultured with expanded polyclonal CD4 T cells enriched using CD137 expression after contact with whole UV-treated ZIKV viral lysate. Data from triplicate assays are mean and standard deviation of IFNγ secretion at 24 hours as measured by ELISA. Insets are 14 to 15 AA peptides internal to NS1 81–100 and their predicted binding to the indicated HLA heterodimers, with core HLA binding motifs bold and underlined. The vertical arrow in the lower portion connects the peptide sequence with HLA DQA1*01:02/DQB1*06:02, the heterodimer used to predict that IC50 value in the figure.