SARS coronavirus nucleocapsid immunodominant T-cell epitope cluster is common to both exogenous recombinant and endogenous DNA-encoded immunogens

Vandana Gupta, Tani M. Tabiin, Kai Sun, Ananth Chandrasekaran, Azlinda Anwar, Kun Yang, Priya Chikhlikar, Jerome Salmon, Vladimir Brusic, Ernesto T A Marques, Srinivasan N. Kellathur, Thomas J. August

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

Correspondence between the T-cell epitope responses of vaccine immunogens and those of pathogen antigens is critical to vaccine efficacy. In the present study, we analyzed the spectrum of immune responses of mice to three different forms of the SARS coronavirus nucleocapsid (N): (1) exogenous recombinant protein (N-GST) with Freund's adjuvant; (2) DNA encoding unmodified N as an endogenous cytoplasmic protein (pN); and (3) DNA encoding N as a LAMP-1 chimera targeted to the lysosomal MHC II compartment (p-LAMP-N). Lysosomal trafficking of the LAMP/N chimera in transfected cells was documented by both confocal and immunoelectron microscopy. The responses of the immunized mice differed markedly. The strongest T-cell IFN-γ and CTL responses were to the LAMP-N chimera followed by the pN immunogen. In contrast, N-GST elicited strong T cell IL-4 but minimal IFN-γ responses and a much greater antibody response. Despite these differences, however, the immunodominant T-cell ELISpot responses to each of the three immunogens were elicited by the same N peptides, with the greatest responses being generated by a cluster of five overlapping peptides, N76-114, each of which contained nonameric H2d binding domains with high binding scores for both class I and, except for N 76-93, class II alleles. These results demonstrate that processing and presentation of N, whether exogenously or endogenously derived, resulted in common immunodominant epitopes, supporting the usefulness of modified antigen delivery and trafficking forms and, in particular, LAMP chimeras as vaccine candidates. Nevertheless, the profiles of T-cell responses were distinctly different. The pronounced Th-2 and humoral response to N protein plus adjuvant are in contrast to the balanced IFN-γ and IL-4 responses and strong memory CTL responses to the LAMP-N chimera.

Original languageEnglish
Pages (from-to)127-139
Number of pages13
JournalVirology
Volume347
Issue number1
DOIs
Publication statusPublished - Mar 30 2006
Externally publishedYes

Keywords

  • Antigen peptide epitopes
  • ELISpot
  • LAMP-N DNA construct
  • N DNA construct
  • Nucleocapsid protein
  • Recombinant N
  • Rodent
  • SARS coronavirus
  • T cells

ASJC Scopus subject areas

  • Virology

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