Poster Presentation Asia-Pacific Vaccine and Immunotherapy Congress 2024

Analysis of T-cell responses to the epitopes derived from SARS-CoV-2 nucleocapsid protein presented by HLA Class II alleles in Indonesian population (#163)

Marsia Gustiananda 1 , Caroline Nadia Bahana 1 , Ellen Budiono 1 , Fanie Tansil 1 , Michael Jonathan 1 , Jyothsna Girish 1 , Vivi Julietta 1 , Sita Andarini 2 , Yacine Maringer 3 4 5 , Annika Nelde 3 5 6 , Jaturong Sewatanon 7 , Juliane Walz 3 4 5
  1. Department of Biomedicine, School of Life Sciences, Indonesia International Institute for Life Sciences, Jakarta, Indonesia
  2. Department of Pulmonology and Respiratory Medicine, Faculty of Medicine University of Indonesia -Persahabatan Hospital, Jakarta, DKI Jakarta, Indonesia
  3. Department of Peptide-based Immunotherapy, University and University Hospital Tübingen, Tübingen, Germany
  4. Cluster of Excellence iFIT (EXC2180) "Image-Guided and Functionally Instructed Tumor Therapies", University of Tübingen, Tübingen, Germany
  5. Clinical Collaboration Unit Translational Immunology, German Cancer Consortium (DKTK), Department of Internal Medicine, University Hospital Tübingen, Tuebingen , Germany
  6. Institute for Cell Biology, Department of Immunology, University of Tübingen, Tübingen, Germany
  7. Department of Pulmonology and Respiratory Medicine, Faculty of Medicine Siriraj Hospital, Mahidol University, Bangkoknoi, Bangkok, Thailand

Cell-mediated immunity provided by T-cells is very important to combat SARS-CoV-2 infection. CD8+ T-cells or cytotoxic T-cells (CTL) kill the virus-infected cell thereby removing the virus reservoir and CD4+ T-cells or helper T-cells (HTL) orchestrating the appropriate immune responses and help B-cells to produce antibody. T-cells recognize SARS-CoV-2 peptide presented by human leukocyte antigen (HLA) on the surface of the infected cells. Knowledge about what viral peptides seen by T-cells is very important for vaccine development, immunotherapy and diagnostic. However, as sought in the Immune Epitope Database (IEDB) there remains limited research on the peptide presented by the HLA alleles of the Indonesian population. We conducted immunoinformatics analysis to predict peptides from the SARS-CoV-2 nucleocapsid protein (NP) that are presented by HLA Class II alleles of Indonesian population such as HLA-DRB1*12:02 (allele frequency 36.8%), HLA-DRB1*15:02 (24.1%), and HLA-DRB1*07:01 (13.7%). The immunogenicity of six nucleocapsid protein peptides, predicted to be presented by HLA class II, was validated through interferon gamma enzyme-linked immunospot (IFN-γ ELISpot) assay. One peptide (NP_263-280) has been reported in IEDB, while the remaining five (NP_104-122, NP_125-144, NP_166-183, NP_352-371, and NP_387-406) are new. The IFN-γ ELISpot assay on 23 peripheral blood mononuclear cells (PBMC) samples revealed positive T-cell responses for NP_104-122, NP_125-144, NP_166-183, NP_263-280, and NP_352-371 peptides. Kinetic analysis of T-cell responses toward each epitope shown negative correlation between the number of spots and time since a COVID-19 positive test, suggesting a gradual decline. Enzyme-linked immunosorbent assay (ELISA) was performed on the same samples as ELISpot to measure anti-SARS-CoV-2 NP IgG antibody levels. ELISA on 24 serum samples exhibited significant anti-SARS-CoV-2 NP IgG differences between donors with a history of COVID-19 infection (47.17±22.54 μg/ml) and those without (26.76±12.91 μg/ml) (p=0.036). Kinetic analysis on the antibody level was conducted and compared to the T-cell responses. It was revealed that antibody responses declined more than T-cell responses, emphasizing the durability of T-cells and the importance of understanding long-term T-cell responses.