Shared immunogenic epitopes between host entry and exit proteins from monkeypox and Alaskapox viruses
Authors: Leonardo Pereira de Araújo, Evandro Neves Silva, Patrícia Paiva Corsetti, Leonardo Augusto de Almeida
Journal: The Lancet Microbe (2024)

Studies on emerging and re-emerging infectious diseases are crucial because of the constant threat of epidemics owing to unknown microorganisms or those already identified, with outbreak cases being reported annually.1Choi YK Emerging and re-emerging fatal viral diseases.Exp Mol Med. 2021; 53: 711-712Crossref PubMed Scopus (14) Google Scholar In 2015, a new virus called Alaskapox virus (AKPV) was isolated from an Alaska resident, and on the basis of sequencing, its taxonomy was assigned to the genus Orthopoxvirus (OPXV).2MacNeill AL Comparative pathology of zoonotic orthopoxviruses.Pathogens. 2022; 11: 892Crossref PubMed Scopus (15) Google Scholar In 2024, in The Lancet Infectious Diseases, Sharmila Devi reported the first death caused by AKPV in an immunocompromised patient, which exacerbated disease severity, thus illustrating the importance of a healthy immune system.3Devi S First fatality from Alaskapox virus.Lancet Infect Dis. 2024; (published online March 19)https://doi.org/10.1016/S1473-3099(24)00213-5Summary Full Text Full Text PDF Google Scholar Microorganisms belonging to the OPXV genus are a global threat as they trigger various infectious diseases worldwide.4Babkin IV Babkina IN Tikunova NV An update of Orthopoxvirus molecular evolution.Viruses. 2022; 14: 388Crossref PubMed Scopus (53) Google Scholar In 2022, an outbreak of infections caused by the monkeypox virus (MPXV) was induced by a new variant with mutations that favoured its spread.5Walter K Malani PN What is monkeypox?.JAMA. 2022; 328: 222Crossref PubMed Scopus (30) Google Scholar In 2024, in The Lancet Microbe, Raianna Fantin and Camila Coelho commented on the need for effective vaccines against MPXV considering the low antibody neutralisation levels of currently available vaccines against MPXV.6Fantin RF Coelho CH Human antibody responses to circulating monkeypox virus emphasise the need for the first mpox-specific vaccina.Lancet Microbe. 2024; 5: e204-e205Summary Full Text Full Text PDF PubMed Scopus (0) Google Scholar Because vaccination is a quick and effective strategy and subunit vaccines can be used to discover new vaccine agents, we focused efforts on developing a multiepitope immunogenic vaccine derived from proteins involved in viral entry and exit in host cells.7De Araújo LP Santos NCM Corsetti PP de Almeida LA Immunoinformatic approach for rational identification of immunogenic peptides against host entry and/or exit mpox proteins and potential multiepitope vaccine construction.J Infect Dis. 2024; 229: S285-S292Crossref PubMed Scopus (0) Google Scholar Thus, we aimed to investigate the presence of previously identified epitopes, from an earlier study on MPXV, in AKPV proteins and assess the effect of any mutations. Available genomes of AKPV were obtained from the NCBI database. Alignments between MPXV epitopes previously identified in AKPV proteins were performed. Epitopes with mutations identified in AKPV proteins underwent analyses of antigenicity, allergenicity, and physicochemical properties, as previously described.7De Araújo LP Santos NCM Corsetti PP de Almeida LA Immunoinformatic approach for rational identification of immunogenic peptides against host entry and/or exit mpox proteins and potential multiepitope vaccine construction.J Infect Dis. 2024; 229: S285-S292Crossref PubMed Scopus (0) Google Scholar Nine of ten MPXV proteins exhibited identity and similarity values with AKPV proteins, with only the A-type inclusion protein showing low identity and similarity values (table). Three of the ten epitopes showed 100% conservation among the proteins, and of the remaining seven epitopes, six exhibited missense substitution mutations and only one was completely deleted in AKPV. Of the six epitopes with mutations, two showed antigenicity and physicochemical property values beyond the cutoff threshold (table).TableComparison of MPXV and AKPV proteins and analysis of antigenicity and structural stability by AKPV proteinsMPXV ProteinIdentification of MPXV proteinCorresponding protein in AKPVIdentity (%)Similarity (%)Gaps (%)Epitope in MPXVEpitope in AKPVMutationMutation typeVaxiJenProtparamA17LURP85069.1QED21147.191·2950YFTFGDTALYFTFGDTAL····1·55·9A26L/A30LURP85080.1QED21129.180·189·34SLNTKFKTLNISLNTKFKTLNI····1·527·7L1RURP85026.1QED21242.190·893·50·7LATTAIDPVLATATIEPVT → AA → TD → EMissense substitution1·0100·5∗Stability value outside the cutoff threshold.A33RURP85087.1QED21259.173·877·916·6NYNNYNNYNC····Deletion····H2RURP85034.1QED21222.196·898·40KCVDFGAYFRCVDFGAYFK → RMissense substitution2·4−34·0B5RURP85107.1QED21126.180·986·92·7KGANVNARNRKGANVNARNKR → KMissense substitution1·728·0A27LURP85079.1QED21098.145·953·539·9KSGDLKYTYKSGDIKYTYL → IMissense substitution1·8−10·0A35RURP85095.1QED21225.177·386·52·7RVIGLCIRISHVIGLCIRISR → HMissense substitution1·59·0A36RURP85097.1QED21233.186·995·20VSLKKTNDKWLDIVSLKKNSDKWVDIT → NN → SL → VMissense substitution0·5†Antigenicity value less than the cutoff threshold.−22·0C19LURP84978.1QED21148.188·894·11·1HLAIVPTTRHLAIVPTTR····2·020·9MPXV=monkeypox virus. AKPV=Alaskapox virus.∗ Stability value outside the cutoff threshold.† Antigenicity value less than the cutoff threshold. Open table in a new tab MPXV=monkeypox virus. AKPV=Alaskapox virus. An in-silico evaluation showed that the multiepitope protein was effective in inducing an immune response by producing antibodies capable of neutralising viral proteins before infection and leaving traces in infected cells.2MacNeill AL Comparative pathology of zoonotic orthopoxviruses.Pathogens. 2022; 11: 892Crossref PubMed Scopus (15) Google Scholar These proteins, present on infected cell membranes, can serve as targets for cellular immune response, such as cytolytic CD8 cells.8Kalimuddin S Tham CYL Qui M et al.Early T cell and binding antibody responses are associated with COVID-19 RNA vaccine efficacy onset.Med. 2021; 2: 682-688.e4Summary Full Text Full Text PDF PubMed Google Scholar The presence of conserved proteins or epitopes among different species of microorganisms, with multieffector characteristics in both humoral and cellular responses, has great potential to be widely used. The current report showed the conservation between entry and exit proteins from MPXV and AKPV, including epitopes present in the abovementioned multiepitope construct. Because of the urgency to develop potential vaccines and diagnostic tools, the versatility of the immunoinformatics project assumes some rationality in its use by obtaining fast and promising results to control emerging and re-emerging diseases. In addition to the application of the studied peptide as a vaccine, the peptide can be used in diagnostic tests, including ELISA, for the rapid detection of antibodies present in patients' serum.9Poltavchenko AG Ersh AV Filatov PV Yakubitskiy SN Rapid protocol of dot-immunnoassay for orthopoxviruses detection.J Virol Methods. 2020; 279113859Crossref PubMed Scopus (2) Google Scholar The results showed the presence of conservation sequences and differences that could be used to differentiate between infections caused by MPXV and AKPV. This approach, while not specifically targeted in all cases, is effective and plays an important role in early infection identification.9Poltavchenko AG Ersh AV Filatov PV Yakubitskiy SN Rapid protocol of dot-immunnoassay for orthopoxviruses detection.J Virol Methods. 2020; 279113859Crossref PubMed Scopus (2) Google Scholar The observation of peptide conservation in proteins similar to those in APKV reinforces the relevance of the study, highlighting the potential applicability of the study findings in different contexts. Furthermore, the ability to adapt the study findings to address issues related to MPXV control extends the usefulness of the study, demonstrating a multi-efficient approach that can benefit various public health scenarios. The conserved and non-conserved epitopes between the entry and exit proteins from MPXV and AKPV have potential for use in rapid identification and characterisation tests for diseases caused by the viruses. Further analyses are recommended to assess the conservation of the epitopes in OPXV proteins to ascertain if the conservation occurs across the entire genus. Additionally, the epitopes show promising predictions of antigenicity, allergenicity, and structural stability, suggesting that the epitopes can be effectively used in the prevention and control of diseases caused by APKV and MPXV. We declare no competing interests. The authors acknowledge the financial support by Brazilian agencies. This study was supported in part by the Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES) (Grant/Award Number: 001) and Fundação de Amparo à Pesquisa do Estado de Minas Gerais (FAPEMIG) (Grant/Award Number: BPD-00626-22 and APQ-01297-23). LPDA: conceptualisation, data curation, formal analysis, investigation, methodology, validation, and writing - original draft. ENS: conceptualisation, formal analysis, validation, and writing. PPC and LADA: conceptualisation, data curation, formal analysis, investigation, resources, supervision, validation, visualisation, and writing - original draft.