An Effective CTL Peptide Vaccine for Ebola Zaire Based on Survivors’ CD8+ Targeting of a Particular Nucleocapsid Protein Epitope with Potential Implications for COVID-19 Vaccine Design

CV Herst; S Burkholz; J Sidney; A Sette; PE Harris; S Massey; T Brasel; E Cunha-Neto; DS Rosa; WCH Chao; R Carback; T Hodge; L Wang; S Ciotlos; P Lloyd; R Rubsamen

Wilson reported that protection seen in her experiment was due to a peptide sequence within NP-43-53. We hypothesized that the NP43-53 epitope was inefficiently processed into MHC binding sub-sequences during antigen presentation. In order to explore possible H2-D b matches for peptide sequences 95 contained within Ebola Zaire NP43-53 (VYQVNNLEEIC), we prepared three peptide vaccine formulations, each containing one of the three possible 9mer sub-sequences within NP43-53. These sequences are shown in Table 1 . We then vaccinated, via intradermal (tail) injection, three groups of mice with microspheres containing one of the three 9mer sub-sequences of NP43-53 (6 per 100 group). ELISPOT analysis was performed, stimulating harvested splenocytes with the three possible 9mer sub-sequences. Splenocytes from mice receiving the NP44-52 sub-sequence had a statistically higher ELISPOT response than mice vaccinated with the other two possible sub-sequence 9mers (P < 0.0001) as shown in Figure 1a . This is consistent with the predicted H2-D b binding 9mer Sub-sequences of VYQVNNLEEIC . This peptide has a predicted favorable H2-I b binding affinity as shown in Supplementary Material Table 5 .