Characterization of the gene encoding sporozoite surface protein 2, a protective Plasmodium yoelii sporozoite antigen. Mol Biochem Parasitol

Malaria Program, Naval Medical Research Institute, Bethesda, MD 20889-5055.
Molecular and Biochemical Parasitology (Impact Factor: 1.79). 08/1992; 53(1-2):45-51. DOI: 10.1016/0166-6851(92)90005-5
Source: PubMed


Sporozoite surface protein 2 (SSP2) is a 140-kDa, protective sporozoite surface protein from Plasmodium yoelii distinct from the circumsporozoite protein (CSP). A genomic clone containing the SSP2 gene was isolated and sequenced to determine its size, structural organization and deduced primary amino acid sequence. The coding sequence consists of a single, long open reading frame encoding 826 amino acids. The overall structure of SSP2 is similar to that of the CSP, consisting of a central region of immunogenic amino acid repeats flanked by non-repetitive sequence. SSP2 has one copy of a thrombospondin repeat motif in common with several cell adhesion molecules as well as with the CSP and the thrombospondin related anonymous protein (TRAP) of P. falciparum. Additionally, SSP2 shares substantial sequence similarity to TRAP, suggesting that TRAP is the analogue of SSP2 in P. falciparum.

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Available from: Stephen Hoffman, Feb 08, 2015
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    • "The ME-TRAP antigen construct comprises a human codon-optimized multi-epitope string (ME) fused to the native P. falciparum T9/96 strain cDNA sequence encoding TRAP [1]. Also known as sporozoites surface protein 2 [25], TRAP is a type Ia membrane protein with a predicted N-terminal signal peptide, a large ectodomain, a transmembrane domain, and a short cytoplasmic C-terminal domain. This topology is compatible with fusion of the N-terminus of ME-TRAP to the C-terminus of Ii, since the latter is a type II membrane protein with a short cytoplasmic N-terminal domain. "
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    ABSTRACT: The orthodox role of the invariant chain (CD74; Ii) is in antigen presentation to CD4+ T cells, but enhanced CD8+ T cells responses have been reported after vaccination with vectored viral vaccines encoding a fusion of Ii to the antigen of interest. In this study we assessed whether fusion of the malarial antigen, ME-TRAP, to Ii could increase the vaccine-induced CD8+ T cell response. Following single or heterologous prime-boost vaccination of mice with a recombinant chimpanzee adenovirus vector, ChAd63, or recombinant modified vaccinia virus Ankara (MVA), higher frequencies of antigen-specific CD4+ and CD8+ T cells were observed, with the largest increases observed following a ChAd63-MVA heterologous prime-boost regimen. Studies in non-human primates confirmed the ability of Ii-fusion to augment the T cell response, where a 4-fold increase was maintained up to 11 weeks after the MVA boost. Of the numerous different approaches explored to increase vectored vaccine induced immunogenicity over the years, fusion to the invariant chain showed a consistent enhancement in CD8+ T cell responses across different animal species and may therefore find application in the development of vaccines against human malaria and other diseases where high levels of cell-mediated immunity are required.
    Full-text · Article · Jun 2014 · PLoS ONE
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    • "E-mail address: (B.T. Beerntsen). cumsporozoite (CS) protein and thrombospondin-related adhesive protein (TRAP)/sporozoite surface protein (SSP) are surface molecules that have been well-characterized and shown to play vital roles in sporozoite biology [2] [3] [4]. The CS protein has been demonstrated to not only be critical for sporozoite budding during oocyst differentiation, but it also has been implicated in the invasion of mosquito salivary glands and vertebrate liver tissue [5] [6] [7] [8]. "
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    ABSTRACT: The Plasmodium sporozoite is infective for mosquito salivary glands and vertebrate host tissues. Although it is a key developmental stage of the malaria parasite, relatively few sporozoite surface or secreted proteins have been identified and characterized. Herein, we describe the molecular and cellular characterization of a novel surface molecule that is preferentially-expressed in salivary gland sporozoites as compared to oocyst and hemolymph sporozoites. This molecule, designated the sporozoite and erythrocytic stages (SES) protein (formerly known as Pg4), exhibits a spiral surface labeling pattern that spans over a known sporozoite surface antigen, the circumsporozoite protein, with only minor co-localization. SES consists of 551 amino acids encoding a putative 63.2kDa protein that has been shown to be expressed not only on particular sporozoite stages, but also during the asexual and gametocyte stages. This novel protein also has three domains of unknown function that are conserved in at least eight Plasmodium spp. that represent human, avian, non-human primate, and rodent malarias.
    Full-text · Article · Sep 2006 · Molecular and Biochemical Parasitology
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    • "Our study revealed that the recombinant PvTRAP was insoluble and present in inclusion bodies. We are reporting for the first time the expression, purification and characterization of PvTRAP, even though, earlier studies on TRAP only reported the complete sequence of P. yoelii sporozoite surface protein 2 (SSP2) gene (34), characterization of P. falciparum SSP2 (6), cloning and cross species comparison of P. knowlesi, P. vivax and P. gallinaceum (9), and also sequence analysis of P. cynomolgi TRAP (10). In the present study, eluted recombinant PvTRAP was subjected to multi-stage purification procedure, as shown in Figure 2. Single band purified, refolded PvTRAP was generated (Fig. 3a) and further analyzed under different conditions (Fig. 3a & b, 4, 5a-b). "
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    ABSTRACT: Thrombospondin Related Adhesive Protein (TRAP) is a transmembrane parasite molecule responsible in sporozoite-host interactions. This molecule is one of the most promising vaccine candidates against the pre-erythrocytic forms of malaria. In the present study, a gene encoding the Plasmodium vivax TRAP (PvTRAP) was expressed in Escherichia coli (M15 strain) using the expression plasmid pQE30. The expressed recombinant protein PvTRAP of about 70kDa was achieved, purified and refolded according to the standardized refolding procedure. This refolded protein (PvTRAP) showed a single band monomeric form with SDS-PAGE and blot analysis. In reduced and alkylated form, PvTRAP showed less binding to hepatoma (HepG2) liver cells, when compared to the normal purified and refolded form. Purified and refolded recombinant PvTRAP bound Duffy-positive human erythrocytes, while no binding was observed with Duffy-negative erythrocytes. Our report on PvTRAP is currently documented for the first time and it has been able to provide an experimental evidence of the biochemical and binding properties of PvTRAP in the invasion of hepatocytes and interaction with Duffy-positive and Duffy-negative human erythrocytes. In conclusion, our findings have been able to demonstrate the potential of PvTRAP as a promising target for vivax malaria vaccine candidate.
    Full-text · Article · Sep 2006
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