{
  "abstract": "Infections due to Cryptococcus species are estimated to cause over 100,000 deaths a year. No cryptococcal vaccines are approved for human use. We have shown that vaccine formulations consisting of C. neoformans chitin deacetylase 2 (Cda2) and Cda1 adjuvanted with Cationic Adjuvant Formulation 01 (CAF01) protect mice against experimental cryptococcosis by a mechanism dependent upon CD4 ⁺ T cells. Here, using overlapping peptide libraries, we mapped epitopes in Cda2 and Cda1 that stimulated interferon-gamma (IFNγ) release from splenocytes of C57BL/6 and DR4 mice immunized with these proteins. DR4 mice lack mouse major histocompatibility class II (MHC-II) proteins and express chimeric MHC-II proteins with the specificity of the human HLA-DR allele, HLA-DRB1*04:01. Experimental results were then compared with MHC-II binding predictions using the Immune Epitope Database NetMHCIIpan 4.1 BA MHC-II epitope prediction tool. Unique epitopes in Cda2 and Cda1 were discovered for each mouse strain, some of which were not predicted to bind well to MHC-II. CD4 ⁺ T cells were responsible for cytokine release as IFNγ production was lost if CD4 ⁺ T cells were depleted from the splenocyte population. Finally, we tested a hybrid recombinant protein that consisted of portions of Cda2 and Cda1 containing the MHC-II/CD4 ⁺ T-cell epitopes that induce CD4 ⁺ T cells in DR4 mice. When administered as a CAF01-adjuvanted vaccine, the hybrid protein protected DR4 mice from an otherwise lethal C. neoformans pulmonary challenge. These results provide a proof of principle regarding the utility of MHC-II/CD4 ⁺ T-cell epitope mapping in cryptococcal vaccine development.\n\nIMPORTANCE: The development of vaccines to prevent cryptococcosis, a fungal disease which causes over 100,000 deaths annually, is a public health priority. We have demonstrated that adjuvanted vaccines containing two Cryptococcus neoformans protein antigens, chitin deacetylase (Cda)2 and Cda1, protect mice against experimental cryptococcosis by a mechanism dependent upon CD4 ⁺ T cells. In this study, we determined which 15-amino-acid peptides of Cda2 and Cda1 stimulate CD4 ⁺ T cells in C57BL/6 and DR4 mice; the latter mouse strain has human major histocompatibility class II (MHC-II) specificity. We then synthesized a small hybrid protein containing those portions of Cda2 and Cda1 that strongly stimulated CD4 ⁺ T-cell responses in DR4 mice. As an adjuvanted vaccine, the hybrid Cda2/1 protein protected DR4 mice from a C. neoformans pulmonary challenge. Thus, CD4 ⁺ T-cell/MHC-II epitope mapping experimentally validated the design of a protective multi-epitope protein for use in cryptococcal vaccines.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Medicine, University of Massachusetts Chan Medical School",
    "Center for Vaccine Research, Statens Serum Institut"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "Charles A. Specht",
      "orcid": "0000-0002-5749-3112"
    },
    {
      "affs": [
        0
      ],
      "name": "Lorena V. N. Oliveira",
      "orcid": "0000-0002-1762-0076"
    },
    {
      "affs": [
        0
      ],
      "name": "Diana Carlson",
      "orcid": "0009-0009-5268-0646"
    },
    {
      "affs": [
        0
      ],
      "name": "Maureen M. Hester",
      "orcid": "0000-0002-2680-4854"
    },
    {
      "affs": [
        0
      ],
      "name": "Satya Sahu",
      "orcid": "0000-0001-5762-439X"
    },
    {
      "affs": [
        1
      ],
      "name": "Gabriel Kristian Pedersen",
      "orcid": "0000-0001-6872-3975"
    },
    {
      "affs": [
        0
      ],
      "name": "Stuart M. Levitz",
      "orcid": "0000-0002-3799-3064"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/8vfmzhes5n8bg.bib",
  "cited_by": 1,
  "doi": "10.1128/mbio.02176-26",
  "fulltext_url": null,
  "id": "8vfmzhes5n8bg",
  "issns": [
    "2150-7511"
  ],
  "landing_url": "https://journals.asm.org/doi/10.1128/mbio.02176-26",
  "language": null,
  "licence": "CC-BY-4.0",
  "licence_label": "CC BY 4.0",
  "licence_source": "article",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1312|vaccines and immunoinformatics approaches"
    ]
  ],
  "openalex": "W7221835429",
  "pdf_url": "https://journals.asm.org/doi/pdf/10.1128/mbio.02176-26",
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-14",
  "publisher": "American Society for Microbiology",
  "ris": "https://research.draconitic.com/paper/8vfmzhes5n8bg.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:19:28Z",
      "native_id": "10.1128/mbio.02176-26",
      "source": "crossref",
      "url": "https://journals.asm.org/doi/10.1128/mbio.02176-26"
    }
  ],
  "subjects": [
    {
      "field": "biochemistry",
      "origin": "openalex:1312|vaccines and immunoinformatics approaches",
      "subfield": "molecular-biology"
    }
  ],
  "title": "A protective hybrid protein vaccine informed by mapping major histocompatibility class II epitopes in Cryptococcus neoformans chitin deacetylases that stimulate CD4 ⁺ T-cell responses",
  "title_text": "A protective hybrid protein vaccine informed by mapping major histocompatibility class II epitopes in Cryptococcus neoformans chitin deacetylases that stimulate CD4 ⁺ T-cell responses",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T12:19:28Z",
  "url": "https://research.draconitic.com/paper/8vfmzhes5n8bg",
  "venue": "mBio",
  "versions": []
}