Immune Response of Zika prM Peptide PEG Conjugates in Peripheral Blood Mononuclear Cells

Despite the challenge in generating adequate immunogenicity, peptide-based vaccines offer a significant benefit in terms of improving immunity when combined with conjugates. In previous studies, three computationally designed immunogenic peptides of the Zika prM protein were reported to induce an immune response. In the current work, reported peptides were conjugated with polymer, polyethylene glycol 400, with the intention of enhancing the immune response. Conjugation was confirmed by Fourier transform infrared spectroscopy. We reckoned the immune response of all three peptide-PEG conjugates (MPC1, MPC2, and MPC3) on 10 different healthy blood samples. Assessment of MPC-induced human peripheral blood mononuclear cell (PBMC) proliferation and interferon-gamma (IFN-γ) secretion was done with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay and a sandwich enzyme-linked immunosorbent assay (ELISA). Conjugate MPC1 showed significantly enhanced cell proliferation in five and MPC2 and MPC3 in six samples, compared to the peptides. In case of IFN-γ release, conjugate MPC1 exhibited significant results in six, MPC2 in five, and MPC3 in seven samples elevated results, in contrast to peptides alone. Thus, conjugation of PEG to immunogenic peptides could be an effective way to increase the peptide immunogenicity, although further experimental validations are required before considering them as candidates for a vaccine against Zika virus infection.