Circumsporozoite (CS) protein is the major surface component of Plasmodium falciparum sporozoites and is essential for host cell invasion. A vaccine containing tandem repeats, region III, and thrombospondin type-I repeat (TSR) of CS is efficacious in phase III trials but gives only a 35% reduction in severe malaria in the first year postimmunization. We solved crystal structures showing that region III and TSR fold into a single unit, an "αTSR" domain. The αTSR domain possesses a hydrophobic pocket and core, missing in TSR domains. CS binds heparin, but αTSR does not. Interestingly, polymorphic T-cell epitopes map to specialized αTSR regions. The N and C termini are unexpectedly close, providing clues for sporozoite sheath organization. Elucidation of a unique structure of a domain within CS enables rational design of next-generation subunit vaccines and functional and medicinal chemical investigation of the conserved hydrophobic pocket.
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http://dx.doi.org/10.1073/pnas.1205737109 | DOI Listing |
Vaccines (Basel)
January 2025
Division of Infectious Diseases, Cincinnati Children's Hospital Medical Center, 3333 Burnet Avenue, Cincinnati, OH 45229, USA.
Background: Noroviruses, which cause epidemic acute gastroenteritis, and parasites, which lead to malaria, are two infectious pathogens that pose threats to public health. The protruding (P) domain of norovirus VP1 and the αTSR domain of the circumsporozoite protein (CSP) of sporozoite are the glycan receptor-binding domains of the two pathogens for host cell attachment, making them excellent targets for vaccine development. Modified norovirus P domains self-assemble into a 24-meric octahedral P nanoparticle (P NP).
View Article and Find Full Text PDFNPJ Vaccines
January 2025
Jenner Institute, University of Oxford, and the NIHR Oxford Biomedical Research Centre, Oxford, OX3 7DQ, UK.
The primary immunological readout for clinical trials of R21/MatrixM™ malaria vaccine, is total IgG antibody specific to the central four amino acid NANP repeat region of the circumsporozoite protein. A multiplexed assay, which includes NANP, was developed and validated for four antigens representing components of the R21 immunogen. Initial assay optimisation included validation of the HBsAg international standard.
View Article and Find Full Text PDFElife
January 2025
Department of Medical Microbiology, Radboud University Medical Center, Nijmegen, Netherlands.
Circulating sexual stages of ) can be transmitted from humans to mosquitoes, thereby furthering the spread of malaria in the population. It is well established that antibodies can efficiently block parasite transmission. In search for naturally acquired antibodies targets on sexual stages, we established an efficient method for target-agnostic single B cell activation followed by high-throughput selection of human monoclonal antibodies (mAbs) reactive to sexual stages of in the form of gametes and gametocyte extracts.
View Article and Find Full Text PDFFront Parasitol
April 2024
Centre for Malaria Elimination, Institute of Tropical Medicine, Mount Kenya University, Thika, Kenya.
The Circumsporozoite Protein (PfCSP) has been used in developing the RTS,S, and R21 malaria vaccines. However, genetic polymorphisms within compromise the effectiveness of the vaccine. Thus, it is essential to continuously assess the genetic diversity of , especially when deploying it across different geographical regions.
View Article and Find Full Text PDFLancet Microbe
December 2024
Jenner Institute, University of Oxford-NIHR Oxford Biomedical Research Centre, Oxford, UK. Electronic address:
Background: Malaria remains a substantial public health burden among young children in sub-Saharan Africa and a highly efficacious vaccine eliciting a durable immune response would be a useful tool for controlling malaria. R21 is a malaria vaccine comprising nanoparticles, formed from a circumsporozoite protein and hepatitis B surface antigen (HBsAg) fusion protein, without any unfused HBsAg, and is administered with the saponin-based Matrix-M adjuvant. This study aimed to assess the safety and immunogenicity of the malaria vaccine candidate, R21, administered with or without adjuvant Matrix-M in adults naïve to malaria infection and in healthy adults from malaria endemic areas.
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