Research Article| Volume 249, P28-36, November 2022

Cyclic constrained immunoreactive peptides from crucial P. falciparum proteins: potential implications in malaria diagnostics

      Malaria is still a global challenge with significant morbidity and mortality, especially in the African, South-East Asian, and Latin American regions. Malaria diagnosis is a crucial pillar in the control and elimination efforts, often accomplished by the administration of mass-scale Rapid diagnostic tests (RDTs). The inherent limitations of RDTs- insensitivity in scenarios of low transmission settings and deletion of one of the target proteins- Histidine rich protein 2/3 (HRP-2/3) are evident from multiple reports, thus necessitating the need to explore novel diagnostic tools/targets. The present study used peptide microarray to screen potential epitopes from 13 antigenic proteins (CSP, EXP1, LSA1, TRAP, AARP, AMA1, GLURP, MSP1, MSP2, MSP3, MSP4, P48/45, HAP2) of P. falciparum. Three cyclic constrained immunoreactive peptides- C6 (EXP1), A8 (MSP2), B7 (GLURP) were identified from 5458 cyclic constrained peptides (in duplicate) against P. falciparum-infected sera. Peptides (C6, A8, B7- cyclic constrained) and (G11, DSQ, NQN- corresponding linear peptides) were fairly immunoreactive towards P. falciparum-infected sera in dot-blot assay. Using direct ELISA, cyclic constrained peptides (C6 and B7) were found to be specific to P. falciparum-infected sera. A substantial number of samples were tested and the peptides successfully differentiated the P. falciparum positive and negative samples with high confidence. In conclusion, the study identified 3 cyclic constrained immunoreactive peptides (C6, B7, and A8) from P. falciparum secretory/surface proteins and further validated for diagnostic potential of 2 peptides (C6 and B7) with field-collected P. falciparum-infected sera samples.


      CSP (circumsporozoite protein), EXP1 (exported protein 1), LSA1 (liver stage antigen 1), TRAP (thromobospondin-related anonymous protein), AARP (apical asparagine rich protein), GLURP (glutamate rich protein), MSP1 (merozoite surface protein 1), MSP2 (merozoite surface protein 2), MSP3 (merozoite surface protein 3), MSP4 (merozoite surface protein 4)
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      1. World malaria report 2020. Accessed June 6, 2021.

        • Laurent A.
        • Schellenberg J.
        • Shirima K.
        • et al.
        Performance of HRP-2 based rapid diagnostic test for malaria and its variation with age in an area of intense malaria transmission in southern tanzania.
        Malar. J. 2010; 9: 294
        • Makler M.T.
        • Piper R.C.
        • Milhous W.K.
        Lactate dehydrogenase and the diagnosis of malaria.
        Parasitol. Today. 1998; 14: 376-377
        • Bharti P.K.
        • Chandel H.S.
        • Ahmad A.
        • et al.
        Prevalence of pfhrp2 and/or pfhrp3 gene deletion in plasmodium falciparum population in eight highly endemic states in India.
        PLoS One. 2016; 11: 1-16
        • Wangdi K.
        • Gatton M.L.
        • Kelly G.C.
        • Banwell C.
        • Dev V.
        • Clements A.C.A.
        Malaria elimination in India and regional implications.
        Lancet Infect. Dis. 2016; 16: e214-e224
        • Balikagala B.
        • Fukuda N.
        • Ikeda M.
        • et al.
        Evidence of Artemisinin-Resistant Malaria in Africa.
        N. Engl. J. Med. 2021; 385: 1163-1171
        • Bartholdson S.J.
        • Crosnier C.
        • Bustamante L.Y.
        • Rayner J.C.
        • Wright G.J.
        Identifying novel Plasmodium falciparum erythrocyte invasion receptors using systematic extracellular protein interaction screens.
        Cell. Microbiol. 2013; 15: 1304-1312
        • Harris P.K.
        • Yeoh S.
        • Dluzewski A.R.
        • et al.
        Molecular identification of a malaria merozoite surface sheddase.
        PLoS Pathog. 2005; 1 (Epub 2005 Nov 25): 241-251
        • Kadekoppala M.
        • Holder A.A.
        Merozoite surface proteins of the malaria parasite: The MSP1 complex and the MSP7 family.
        International Journal for Parasitology. 2010; 40: 1155-1161
        • Boyle M.J.
        • Langer C.
        • Chan J.A.
        • et al.
        Sequential processing of merozoite surface proteins during and after erythrocyte invasion by Plasmodium falciparum.
        Infect. Immun. 2014; 82 (Epub 2013 Nov 11): 924-936
        • Baum J.
        • Maier A.G.
        • Good R.T.
        • Simpson K.M.
        • Cowman A.F
        Invasion by P. falciparum merozoites suggests a hierarchy of molecular interactions.
        PLoS Pathog. 2005; 1: 0299-0309
        • Cowman A.F.
        • Berry D.
        • Baum J.
        The cellular and molecular basis for malaria parasite invasion of the human red blood cell.
        J. Cell Biol. 2012; 198: 961-971
        • Tan J.
        • Sack B.K.
        • Oyen D.
        • et al.
        A public antibody lineage that potently inhibits malaria infection through dual binding to the circumsporozoite protein.
        Nat. Med. 2018; 24 (Epub 2018 Mar 19): 401-407
        • Nixon C.E.
        • Park S.
        • Pond-Tor S.
        • et al.
        Identification of protective B-cell epitopes within the novel malaria vaccine candidate Plasmodium falciparum schizont egress antigen 1.
        Clin. Vaccine Immunol. 2017 Jul 5; 24: e00068
        • Jaenisch T.
        • Heiss K.
        • Fischer N.
        • et al.
        High-density peptide arrays help to identify linear immunogenic B-cell epitopes in individuals naturally exposed to malaria infection.
        Mol. Cell. Proteomics. 2019; 18 (Epub 2019 Jan 10. PMID: 30630936; PMCID: PMC6442360): 642-656
      2. Pepperprint. Characterization of Rituximab by Conformational Epitope Mapping and Epitope Substitution Scan. 2022

        • Jiamu Du
        • Wang H.
        • Zhong C.
        • et al.
        Structural basis for recognition of CD20 by therapeutic antibody Rituximab.
        J. Biol. Chem. 2007; 282: 15073-15080