scholarly journals The malaria circumsporozoite protein has two functional domains, each with distinct roles as sporozoites journey from mosquito to mammalian host

2011 ◽  
Vol 208 (2) ◽  
pp. 341-356 ◽  
Author(s):  
Alida Coppi ◽  
Ramya Natarajan ◽  
Gabriele Pradel ◽  
Brandy L. Bennett ◽  
Eric R. James ◽  
...  
Keyword(s):  
Vaccine Development ◽  
Critical Role ◽  
Domain Architecture ◽  
Surface Protein ◽  
Circumsporozoite Protein ◽  
Mammalian Host ◽  
Multifunctional Protein ◽  
Mosquito Midgut ◽  
Cell Adhesive ◽  
Mammalian Liver

Plasmodium sporozoites make a remarkable journey from the mosquito midgut to the mammalian liver. The sporozoite’s major surface protein, circumsporozoite protein (CSP), is a multifunctional protein required for sporozoite development and likely mediates several steps of this journey. In this study, we show that CSP has two conformational states, an adhesive conformation in which the C-terminal cell-adhesive domain is exposed and a nonadhesive conformation in which the N terminus masks this domain. We demonstrate that the cell-adhesive domain functions in sporozoite development and hepatocyte invasion. Between these two events, the sporozoite must travel from the mosquito midgut to the mammalian liver, and N-terminal masking of the cell-adhesive domain maintains the sporozoite in a migratory state. In the mammalian host, proteolytic cleavage of CSP regulates the switch to an adhesive conformation, and the highly conserved region I plays a critical role in this process. If the CSP domain architecture is altered such that the cell-adhesive domain is constitutively exposed, the majority of sporozoites do not reach their target organs, and in the mammalian host, they initiate a blood stage infection directly from the inoculation site. These data provide structure–function information relevant to malaria vaccine development.

scholarly journals The Plasmodium falciparum circumsporozoite protein produced in Lactococcus lactis is pure and stable

2019 ◽  
Vol 295 (2) ◽  
pp. 403-414 ◽  
Author(s):  
Susheel K. Singh ◽  
Jordan Plieskatt ◽  
Bishwanath Kumar Chourasia ◽  
Vandana Singh ◽  
Judith M. Bolscher ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Lactococcus Lactis ◽  
Malaria Vaccine ◽  
Vaccine Development ◽  
Expression System ◽  
Surface Protein ◽  
Circumsporozoite Protein ◽  
Full Length

The Plasmodium falciparum circumsporozoite protein (PfCSP) is a sporozoite surface protein whose role in sporozoite motility and cell invasion has made it the leading candidate for a pre-erythrocytic malaria vaccine. However, production of high yields of soluble recombinant PfCSP, including its extensive NANP and NVDP repeats, has proven problematic. Here, we report on the development and characterization of a secreted, soluble, and stable full-length PfCSP (containing 4 NVDP and 38 NANP repeats) produced in the Lactococcus lactis expression system. The recombinant full-length PfCSP, denoted PfCSP4/38, was produced initially with a histidine tag and purified by a simple two-step procedure. Importantly, the recombinant PfCSP4/38 retained a conformational epitope for antibodies as confirmed by both in vivo and in vitro characterizations. We characterized this complex protein by HPLC, light scattering, MS analysis, differential scanning fluorimetry, CD, SDS-PAGE, and immunoblotting with conformation-dependent and -independent mAbs, which confirmed it to be both pure and soluble. Moreover, we found that the recombinant protein is stable at both frozen and elevated-temperature storage conditions. When we used L. lactis–derived PfCSP4/38 to immunize mice, it elicited high levels of functional antibodies that had the capacity to modify sporozoite motility in vitro. We concluded that the reported yield, purity, results of biophysical analyses, and stability of PfCSP4/38 warrant further consideration of using the L. lactis system for the production of circumsporozoite proteins for preclinical and clinical applications in malaria vaccine development.

scholarly journals Fluorescent tagging of Plasmodium circumsporozoite protein allows imaging of sporozoite formation but blocks egress from oocysts

2020 ◽  
Author(s):  
Mirko Singer ◽  
Friedrich Frischknecht
Keyword(s):  
Fluorescent Protein ◽  
Surface Protein ◽  
Dominant Negative ◽  
Circumsporozoite Protein ◽  
Negative Function ◽  
Mammalian Liver ◽  
Parasite Replication ◽  
Fluorescent Tagging ◽  
Green Fluorescent ◽  
Major Surface

AbstractThe circumsporozoite protein, CSP is the major surface protein of Plasmodium sporozoites, the form of malaria parasites transmitted by mosquitoes. CSP is involved in sporozoite formation within and egress from oocysts, entry into mosquito salivary glands and mammalian liver as well as migration in the skin. Antibodies against CSP can stop infection prior to the first round of parasite replication in the liver. CSP consists of different domains and is proteolytically cleaved prior to hepatocyte invasion. Part of CSP has been developed into a licensed vaccine against malaria. Yet, how CSP facilitates sporozoite formation, oocyst egress and hepatocyte specific invasion is still not fully understood. Here, we generated a series of parasites expressing full-length versions of CSP as fusion proteins with the green fluorescent protein. This enabled the investigation of sporozoite formation in living oocysts and revealed a dominant negative function of some GFP-CSP fusions during sporozoite egress.

scholarly journals A longitudinal study of SARS-CoV-2-infected patients reveals a high correlation between neutralizing antibodies and COVID-19 severity

2021 ◽  
Author(s):  
Vincent Legros ◽  
Solène Denolly ◽  
Manon Vogrig ◽  
Bertrand Boson ◽  
Eglantine Siret ◽  
...  
Keyword(s):  
Intensive Care ◽  
Neutralizing Antibodies ◽  
Vaccine Development ◽  
Surface Protein ◽  
Humoral Response ◽  
Neutralizing Antibody ◽  
Rapid Decline ◽  
Serum Samples ◽  
Immune Correlates ◽  
Human Coronaviruses

AbstractUnderstanding the immune responses elicited by SARS-CoV-2 infection is critical in terms of protection against reinfection and, thus, for public health policy and vaccine development for COVID-19. In this study, using either live SARS-CoV-2 particles or retroviruses pseudotyped with the SARS-CoV-2 S viral surface protein (Spike), we studied the neutralizing antibody (nAb) response in serum samples from a cohort of 140 SARS-CoV-2 qPCR-confirmed infections, including patients with mild symptoms and also more severe forms, including those that required intensive care. We show that nAb titers correlated strongly with disease severity and with anti-spike IgG levels. Indeed, patients from intensive care units exhibited high nAb titers; conversely, patients with milder disease symptoms had heterogeneous nAb titers, and asymptomatic or exclusive outpatient-care patients had no or low nAbs. We found that nAb activity in SARS-CoV-2-infected patients displayed a relatively rapid decline after recovery compared to individuals infected with other coronaviruses. Moreover, we found an absence of cross-neutralization between endemic coronaviruses and SARS-CoV-2, indicating that previous infection by human coronaviruses may not generate protective nAbs against SARS-CoV-2. Finally, we found that the D614G mutation in the spike protein, which has recently been identified as the current major variant in Europe, does not allow neutralization escape. Altogether, our results contribute to our understanding of the immune correlates of SARS-CoV-2-induced disease, and rapid evaluation of the role of the humoral response in the pathogenesis of SARS-CoV-2 is warranted.

scholarly journals The p47phox mouse knock-out model of chronic granulomatous disease.

1995 ◽  
Vol 182 (3) ◽  
pp. 751-758 ◽  
Author(s):  
S H Jackson ◽  
J I Gallin ◽  
S M Holland
Keyword(s):  
Nadph Oxidase ◽  
Chronic Granulomatous Disease ◽  
Fungal Infections ◽  
Critical Role ◽  
Granulomatous Inflammation ◽  
Mammalian Host ◽  
Granulomatous Disease ◽  
Knock Out ◽  
Phagocyte Nadph Oxidase ◽  
Life Threatening

Chronic granulomatous disease (CGD) is caused by a congenital defect in phagocyte reduced nicotinamide dinucleotide phosphate (NADPH) oxidase production of superoxide and related species. It is characterized by recurrent life-threatening bacterial and fungal infections and tissue granuloma formation. We have created a mouse model of CGD by targeted disruption of p47phox, one of the genes in which mutations cause human CGD. Identical to the case in human CGD, leukocytes from p47phox-/- mice produced no superoxide and killed staphylococci ineffectively. p47phox-/- mice developed lethal infections and granulomatous inflammation similar to those encountered in human CGD patients. This model mirrors human CGD and confirms a critical role for the phagocyte NADPH oxidase in mammalian host defense.

scholarly journals Functional human IgA targets a conserved site on malaria sporozoites

2021 ◽  
Vol 13 (599) ◽  
pp. eabg2344
Author(s):  
Joshua Tan ◽  
Hyeseon Cho ◽  
Tossapol Pholcharee ◽  
Lais S. Pereira ◽  
Safiatou Doumbo ◽  
...  
Keyword(s):  
Critical Role ◽  
Parasite Burden ◽  
Circumsporozoite Protein ◽  
Amino Terminus ◽  
Endemic Region ◽  
Serum Iga ◽  
Iga Response ◽  
Functional Antibodies ◽  
Mucosal Pathogens

Immunoglobulin (Ig)A antibodies play a critical role in protection against mucosal pathogens. However, the role of serum IgA in immunity to nonmucosal pathogens, such as Plasmodium falciparum, is poorly characterized, despite being the second most abundant isotype in blood after IgG. Here, we investigated the circulating IgA response in humans to P. falciparum sporozoites that are injected into the skin by mosquitoes and migrate to the liver via the bloodstream to initiate malaria infection. We found that circulating IgA was induced in three independent sporozoite-exposed cohorts: individuals living in an endemic region in Mali, malaria-naïve individuals immunized intravenously with three large doses of irradiated sporozoites, and malaria-naïve individuals exposed to a single controlled mosquito bite infection. Mechanistically, we found evidence in an animal model that IgA responses were induced by sporozoites at dermal inoculation sites. From malaria-resistant individuals, we isolated several IgA monoclonal antibodies that reduced liver parasite burden in mice. One antibody, MAD2-6, bound to a conserved epitope in the amino terminus of the P. falciparum circumsporozoite protein, the dominant protein on the sporozoite surface. Crystal structures of this antibody revealed a unique mode of binding whereby two Fabs simultaneously bound either side of the target peptide. This study reveals a role for circulating IgA in malaria and identifies the amino terminus of the circumsporozoite protein as a target of functional antibodies.

scholarly journals Role of Pulmonary Surfactant in Gas Exchange Mechanism and Providing Protection against Progression of any Respiratory Viral Disease like SARS-CoV-2 and Need to focus it as First Point of Medication for all Respiratory Diseases

2021 ◽  
Author(s):  
Makarand Phadke
Keyword(s):  
Gas Exchange ◽  
Pulmonary Surfactant ◽  
Vaccine Development ◽  
Critical Role ◽  
Physical Property ◽  
Lower Surface ◽  
Viral Disease ◽  
Type I ◽  
Mucosal Layer ◽  
Unique Physical Property

Abstract During inhalation oxygen molecules are drawn towards type I cells. The partial pressure difference and solubility factor act as a Drive for this movement of oxygen molecules.It is well known that the pulmonary surfactant plays an important role in gas exchange. The surfactant is thin mono-layer. The top surface of surfactant with SP-B and C proteins faces alveolar air and is hydrophobic in nature and acts as a surface tension reducer, whereas lower surface with SP-A and D proteins, is hydrophilic and is adsorbed on mucosal layer. This lower surface of surfactant acts as an anti invader, pathogen barrier. However there is a small missing link in explaining its exact mechanism or role in justifying these properties during normal conditions and during ‘viral ligand’ attack.Similarly a unique physical property of SP- C component is listed in research papers; however its application is not researched anywhere. SP-C has a dielectric constant of 2 to 3 and plays a very critical role in drastically reducing progression of any respiratory viral disease including SARS-CoV-2. This hypothesis targets to explain both micro mechanisms with the help of basic laws of physics, and fluid mechanics. The figures/sketches, drawn also depict the physics involved and not much of a physiology or genetic codes etc. Two examples, in the industry, are briefly listed in the last paragraphs to draw some parallel with above mechanisms.Vaccination is a proven method for containment of a particular respiratory viral disease, if not its cure. But if focus is also given on health of pulmonary surfactant with respect to pathogenesis of any respiratory viral disease, and development of a broad spectrum medication on it; probable loss of lot many lives can be avoided and vaccine development and vaccination management related issues can be less panicky.

scholarly journals Targeted Disruption of the Plasmodium berghei Ctrp Gene Reveals Its Essential Role in Malaria Infection of the Vector Mosquito

1999 ◽  
Vol 190 (11) ◽  
pp. 1711-1716 ◽  
Author(s):  
Masao Yuda ◽  
Hiroshi Sakaida ◽  
Yasuo Chinzei
Keyword(s):  
Plasmodium Berghei ◽  
Malaria Infection ◽  
Molecular Mechanisms ◽  
Mammalian Host ◽  
Insect Vector ◽  
Wild Type ◽  
Mosquito Midgut ◽  
Parasite Plasmodium ◽  
Vector Mosquito ◽  
Stage 1

CTRP (circumsporozoite protein and thrombospondin-related adhesive protein [TRAP]-related protein) of the rodent malaria parasite Plasmodium berghei (PbCTRP) makes up a protein family together with other apicomplexan proteins that are specifically expressed in the host-invasive stage 1. PbCTRP is produced in the mosquito-invasive, or ookinete, stage and is a protein candidate for a role in ookinete adhesion and invasion of the mosquito midgut epithelium. To demonstrate involvement of PbCTRP in the infection of the vector, we performed targeting disruption experiments with this gene. PbCTRP disruptants showed normal exflagellation rates and development into ookinetes. However, no oocyst formation was observed in the midgut after ingestion of these parasites, suggesting complete loss of their invasion ability. On the other hand, when ingested together with wild-type parasites, disruptants were able to infect mosquitoes, indicating that the PbCTRP gene of the wild-type parasite rescued infectivity of disruptants when they heterologously mated in the mosquito midgut lumen. Our results show that PbCTRP plays a crucial role in malaria infection of the mosquito midgut and suggest that similar molecular mechanisms are used by malaria parasites to invade cells in the insect vector and the mammalian host.

scholarly journals The environment and species affect gut bacteria composition in laboratory co-cultured Anopheles gambiae and Aedes albopictus mosquitoes

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sally A. Saab ◽  
Heinrich zu Dohna ◽  
Louise K. J. Nilsson ◽  
Piero Onorati ◽  
Johnny Nakhleh ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Aedes Albopictus ◽  
Food Source ◽  
Mosquito Species ◽  
Critical Role ◽  
Microbiota Composition ◽  
Human Pathogens ◽  
Multiple Factors ◽  
Mosquito Midgut ◽  
Environmental Contribution

AbstractThe midgut microbiota of disease vectors plays a critical role in the successful transmission of human pathogens. The environment influences the microbiota composition; however, the relative mosquito-species contribution has not been rigorously disentangled from the environmental contribution to the microbiota structure. Also, the extent to which the microbiota of the adult sugar food source and larval water can predict that of the adult midgut and vice versa is not fully understood. To address these relationships, larvae and adults of Anopheles gambiae and Aedes albopictus were either reared separately or in a co-rearing system, whereby aquatic and adult stages of both species shared the larval water and sugar food source, respectively. Despite being reared under identical conditions, clear intra- and interspecies differences in midgut microbiota-composition were observed across seven cohorts, collected at different time points over a period of eight months. Fitting a linear model separately for each OTU in the mosquito midgut showed that two OTUs significantly differed between the midguts of the two mosquito species. We also show an effect for the sugar food source and larval water on the adult midgut microbiota. Our findings suggest that the mosquito midgut microbiota is highly dynamic and controlled by multiple factors.

scholarly journals SSP3 Is a Novel Plasmodium yoelii Sporozoite Surface Protein with a Role in Gliding Motility

2014 ◽  
Vol 82 (11) ◽  
pp. 4643-4653 ◽  
Author(s):  
Anke Harupa ◽  
Brandon K. Sack ◽  
Viswanathan Lakshmanan ◽  
Nadia Arang ◽  
Alyse N. Douglass ◽  
...  
Keyword(s):  
Salivary Glands ◽  
Biological Activities ◽  
Surface Protein ◽  
Plasmodium Yoelii ◽  
Gliding Motility ◽  
Surface Proteins ◽  
Type I ◽  
Content Type ◽  
Mosquito Midgut

ABSTRACTPlasmodiumsporozoites develop within oocysts in the mosquito midgut wall and then migrate to the salivary glands. After transmission, they embark on a complex journey to the mammalian liver, where they infect hepatocytes. Proteins on the sporozoite surface likely mediate multiple steps of this journey, yet only a few sporozoite surface proteins have been described. Here, we characterize a novel, conserved sporozoite surface protein (SSP3) in the rodent malaria parasitePlasmodium yoelii. SSP3 is a putative type I transmembrane protein unique toPlasmodium. By using epitope tagging and SSP3-specific antibodies in conjunction with immunofluorescence microscopy, we showed that SSP3 is expressed in mosquito midgut oocyst sporozoites, exhibiting an intracellular localization. In sporozoites derived from the mosquito salivary glands, however, SSP3 localized predominantly to the sporozoite surface as determined by immunoelectron microscopy. However, the ectodomain of SSP3 appeared to be inaccessible to antibodies in nonpermeabilized salivary gland sporozoites. Antibody-induced shedding of the major surface protein circumsporozoite protein (CSP) exposed the SSP3 ectodomain to antibodies in some sporozoites. Targeted deletion ofSSP3adversely affectedin vitrosporozoite gliding motility, which, surprisingly, impacted neither their cell traversal capacity, host cell invasionin vitro, nor infectivityin vivo. Together, these data reveal a previously unappreciated complexity of thePlasmodiumsporozoite surface proteome and the roles of surface proteins in distinct biological activities of sporozoites.

Sign in / Sign up

Export Citation Format

Share Document