Conserved amino acids 193-324 of non-structural protein 3 are a dominant source of peptide determinants for CD4+ and CD8+ T cells in a healthy Japanese encephalitis virus-endemic cohort.
Our earlier identification of the non-structural protein 3 (NS3) of Japanese encephalitis virus (JEV) as a dominant CD4+ as well as CD8+ T cell-eliciting antigen in a healthy JEV-endemic cohort with a wide HLA distribution implied the presence of several epitopes dispersed over the length of the protein. Use of various truncated versions of NS3 in lymphocyte stimulation and interferon (IFN)-gamma secretion assays revealed that amino acids (aa) 193-324 of NS3 were comparable with, if not superior to, the full-length protein in evoking Th1 responses. The potential of this 14.4 kDa stretch to stimulate IFN-gamma production from both subtypes of T cells in a manner qualitatively and quantitatively similar to the 68 kDa parent protein suggested the presence within it of both class I and II epitopes and demonstrated that the entire immunogenicity of NS3 was focused on aa 193-324. Interestingly, this segment contained five of the eight helicase motifs of NS3. Analysis of variability of the NS3 protein sequence across 16 JEV isolates revealed complete identity of aa 219-318, which is contained within the above segment, suggesting that NS3-specific epitopes tend to cluster in relatively conserved regions that harbour functionally critical domains of the protein.
Kumar
Priti
P
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India.
Sulochana
Paramadevanapalli
P
Department of Pediatrics, Vijayanagar Institute of Medical Sciences, Bellary, Karnataka 583104, India.
Nirmala
Gejjehalli
G
Department of Pediatrics, Vijayanagar Institute of Medical Sciences, Bellary, Karnataka 583104, India.
Haridattatreya
Maganti
M
Department of Pediatrics, Vijayanagar Institute of Medical Sciences, Bellary, Karnataka 583104, India.
Satchidanandam
Vijaya
V
Department of Microbiology and Cell Biology, Indian Institute of Science, Bangalore, Karnataka 560012, India.
D000293:Adolescent; D000595:Amino Acid Sequence; D000956:Antigens, Viral / Q000235:genetics* / Q000276:immunology; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology*; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D002478:Cells, Cultured; D002648:Child; D002675:Child, Preschool; D004664:Encephalitis Virus, Japanese / Q000276:immunology*; D004672:Encephalitis, Japanese / Q000453:epidemiology / Q000276:immunology*; D019353:Endemic Diseases; D000939:Epitopes / Q000276:immunology; D005260:Female; D006801:Humans; D007111:Immunity, Cellular; D007194:India / Q000453:epidemiology; D007371:Interferon-gamma / Q000096:biosynthesis; D008297:Male; D008969:Molecular Sequence Data; D020365:RNA Helicases; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins / Q000235:genetics* / Q000276:immunology; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases
D000956:Antigens, Viral; D000939:Epitopes; D007371:Interferon-gamma; D020365:RNA Helicases; D012697:Serine Endopeptidases; D017361:Viral Nonstructural Proteins; C060028:NS3 protein, flavivirus; D043583:Nucleoside-Triphosphatase; D053487:DEAD-box RNA Helicases; D000085242:Viral Proteases