Conjugation of Latent Membrane Protein (LMP)-2 Epitope to Gold Nanoparticles as Highly Immunogenic Multiple Antigenic Peptides for Induction of Epstein−Barr Virus-Specific Cytotoxic T-Lymphocyte Responses in Vitro

Abstract

Nasopharyngeal carcinoma is a neoplasm with a high incidence in Southeast Asia, and it is strongly associated with Epstein-Barr virus (EBV) activation involving the expression of a weakly immunogenic protein, namely, latent membrane protein (LMP)-2. Previous immunological studies already identified the human leukocyte antigen (HLA)-A11 restricted peptide epitope (SSCSSCPLSK) in the LMP-2 antigen. In this work, we prepared gold nanoparticle (AuNP)-peptide conjugate 1 by treating the nanoparticles with the N-cysteinated LMP-2 epitope. The AuNP-peptide conjugates have been characterized by TEM (15-24 nm in diameter) and UV-vis spectroscopy (surface plasmon resonance absorption band at lambda(max) = 520 nm). In the presence of a CALNN capping peptide, the AuNP-peptide conjugates are stable in solution without aggregation at room temperature for at least 48 h. By ELIspot studies, AuNP-peptide conjugate 1 was found to elicit a significantly stronger INF-gamma response [number of spot forming cells (SPC) = 727 +/- 198] from peripheral blood mononuclear cells of healthy HLA-A11 donors when compared to that induced by the unconjugated LMP-2 peptides (SFC = 73 +/- 28). Further studies showed that dendritic cells treated with conjugate 1 can effect CD8+ T-cell activation leading to epitope-specific cytotoxic T lymphocyte killing responses in vitro.

Use of a synthetic foot-and-mouth disease virus peptide conjugated to gold nanoparticles for enhancing immunological response

“…This finding may indicate that AuNPs conjugated to the viral antigen are able to induce T lymphocytes and NK cells to elaborate IFN-γ and trigger a cascade of reactions directed to the immunological regulation of the antiviral immune response. A similar response of the immune system to AuNPs conjugated to a viral antigen was demonstrated earlier [47,48]. IFN-γ, which is a major mediator of inflammation in viral infections, inhibits virus replication in cells, enhances the specific immune response by promoting an increased expression of major histocompatibility complex II, and activates macrophages and NK cells.…”

Cancer Nanotheranostics: Improving Imaging and Therapy by Targeted Delivery Across Biological Barriers

“…Solid gold NPs have also been used for epitope delivery. The peptide epitope of latent membrane protein‐2 from the Epstein–Barr virus organized onto the surface of gold NPs elicits a significantly stronger IFNγ response compared to free epitope in vitro 199. Furthermore, dendritic cells treated with these epitope‐loaded NPs effect CD8+ T cell activation for epitope‐specific cytotoxic T lymphocyte killing responses in vitro.…”

Immunological Properties of Gold Nanoparticles

“…52 GNPs have been named, among other carriers, for application in antigen delivery to dendritic cells. For example, Cheung et al 53 described the use of 15 nm GNPs for presenting a peptide antigen associated with Epstein-Barr virus to dendritic cells. According to their TEM data, peptide-functionalized GNPs penetrated the dendritic cell cytoplasm but were not found in the nuclei.…”