FIG. 7.
EtxB(H57S) is capable of delivering a peptide into the MHC-I antigen presentation pathway. EtxB(H57S)-mediated delivery of class I peptides as assessed by analysis of IL-2 release by RF33.70 T-cell hybridoma. JAWSII cells were incubated with 19-mer peptide alone or peptide admixed with or conjugated to EtxB, EtxB(G33D), or EtxB(H57S) at the equivalent concentration of 100 nM peptide for 2 h. Cells were then fixed with 1% paraformaldehyde and incubated overnight with RF33.70 T-cell hybridoma, specific for SIINFEKL peptide in the context of MHC-I. The 8-mer peptide SIINFEKL and PBS were used as positive and negative control, respectively. Duplicate samples were tested, and presented data are given as means + SEM (error bars).