scholarly journals The Plasmodium circumsporozoite protein is proteolytically processed during cell invasion

2005 ◽  
Vol 201 (1) ◽  
pp. 27-33 ◽  
Author(s):  
Alida Coppi ◽  
Consuelo Pinzon-Ortiz ◽  
Christina Hutter ◽  
Photini Sinnis
Keyword(s):  
Cell Invasion ◽  
Cysteine Protease ◽  
Surface Protein ◽  
Circumsporozoite Protein ◽  
Cysteine Protease Inhibitor ◽  
Target Cells ◽  
Malaria Vaccine Candidate ◽  
Major Surface

The circumsporozoite protein (CSP) is the major surface protein of Plasmodium sporozoites, the infective stage of malaria. Although CSP has been extensively studied as a malaria vaccine candidate, little is known about its structure. Here, we show that CSP is proteolytically cleaved by a papain family cysteine protease of parasite origin. Our data suggest that the highly conserved region I, found just before the repeat region, contains the cleavage site. Cleavage occurs on the sporozoite surface when parasites contact target cells. Inhibitors of CSP processing inhibit cell invasion in vitro, and treatment of mice with E-64, a highly specific cysteine protease inhibitor, completely inhibits sporozoite infectivity in vivo.

scholarly journals Effect of phenyl vinyl sulphone cysteine protease inhibitor on Schistosoma mansoni: in vitro and in vivo experimental studies

2017 ◽  
Vol 41 (4) ◽  
pp. 1049-1058
Author(s):  
Manal Salah El-Din Mahmoud ◽  
Ayman Nabil Ibrahim ◽  
Abeer Fathy Badawy ◽  
Nourhan Mohamed Abdelmoniem
Keyword(s):  
Protease Inhibitor ◽  
Schistosoma Mansoni ◽  
Cysteine Protease ◽  
Experimental Studies ◽  
Cysteine Protease Inhibitor ◽  
Phenyl Vinyl

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.

Anti-leukemia activity of CD33-specific chimeric cytotoxic T lymphocytes in vitro and in vivo is impaired by addition of the CD28 costimulatory endodomain

2007 ◽  
Vol 25 (18_suppl) ◽  
pp. 3052-3052
Author(s):  
A. Dutour ◽  
D. Lee ◽  
S. Napier ◽  
E. Yvon ◽  
H. Finney ◽  
...  
Keyword(s):  
T Cells ◽  
Cytotoxic T Cells ◽  
Surface Protein ◽  
Receptor Expression ◽  
Target Cells ◽  
Chimeric Receptor ◽  
Specific Lysis ◽  
Significant Difference

3052 Background: EBV-specific cytotoxic T cells (EBV-CTLs) expand and have long-term activity in vivo due to the sustained costimulation provided by the EBV-infected cells produced by this persistent virus. We exploited this phenomenon and redirected EBV-CTLs against CD33, a surface protein expressed on the malignant blasts of acute myeloid leukemia (AML) cells. Methods: EBV-CTLs generated from six EBV-seropositive donors were transduced using a retroviral vector encoding CD33 specific chimeric receptor (cR). We evaluated whether the high and sustained activity shown against native EBV+ target cells can be extended to the CD33+ EBV- targets of the chimeric receptor and whether the addition of CD28 signaling domain improved the receptor activity. Results: cRCD33-EBV-CTL maintained killed EBV-LCL and CD33+ targets (specific lysis respectively of 30% and 35% at E:T ratio 25:1). They produced Th-1, Th-2 and Tc cytokines on exposure to CD33+ targets. Addition of the CD28 intracellular domain did not increase cytotoxicity to CD33+ targets. Preincubation of CD33+ cells with the CD33-blocking MoAb resulted in up to 40% inhibition of lysis and up to 60% inhibition of cytokine release by cRCD33-EBV-CTLs confirming the specificity of the TCR interactions with CD33. NOD-SCID mice bearing a human CD33+ AML were injected with EBV-CTLs ×4 weekly starting 5 days after tumor inoculation. Significant tumor reduction was only observed in mice treated with the cRCD33-EBV-CTLs (p<0.05). Immunohistologic analysis showed the presence of a majority of CD8+ human T cells in the tumors of treated mice. Incorporation of the CD28 endodomain resulted in less tumor-infiltrating T cells in mice treated with cRCD33CD28-EBV-CTLs. There was no significant difference in the chemokines receptor expression on cRCD33CD28-EBV-CTLs but their rate of apoptosis was 16 % higher (p<0.05) than the one of cRCD33-EBV-CTLs. Conclusions: EBV- CTL expressing the CD33 chimeric receptor are functional in vitro and in vivo in mice. CD28 signaling may have a deleterious role for the activity of chimeric receptors in vivo. No significant financial relationships to disclose.

scholarly journals Critical Roles of Clostridium difficile Toxin B Enzymatic Activities in Pathogenesis

2014 ◽  
Vol 83 (2) ◽  
pp. 502-513 ◽  
Author(s):  
Shan Li ◽  
Lianfa Shi ◽  
Zhiyong Yang ◽  
Yongrong Zhang ◽  
Gregorio Perez-Cordon ◽  
...  
Keyword(s):  
Clostridium Difficile ◽  
Cysteine Protease ◽  
Lethal Dose ◽  
Enzymatic Activities ◽  
Target Cells ◽  
Content Type ◽  
Cytopathic Effects

TcdB is one of the key virulence factors ofClostridium difficilethat is responsible for causing serious and potentially fatal colitis. The toxin contains at least two enzymatic domains: an effector glucosyltransferase domain for inactivating host Rho GTPases and a cysteine protease domain for the delivery of the effector domain into host cytosol. Here, we describe a novel intrabody approach to examine the role of these enzymes of TcdB in cellular intoxication. By screening a single-domain heavy chain (VHH) library raised against TcdB, we identified two VHH antibodies, 7F and E3, that specifically inhibit TcdB cysteine protease and glucosyltransferase activities, respectively. Cytoplasmic expression of 7F intrabody in Vero cells inhibited TcdB autoprocessing and delayed cellular intoxication, whereas E3 intrabody completely blocked the cytopathic effects of TcdB holotoxin. These data also demonstrate for the first time that toxin autoprocessing occurs after cysteine protease and glucosyltransferase domains translocate into the cytosol of target cells. We further determined the role of the enzymatic activities of TcdB inin vivotoxicity using a sensitive systemic challenge model in mice. Consistent with thesein vitroresults, a cysteine protease noncleavable mutant, TcdB-L543A, delayed toxicity in mice, whereas glycosyltransferase-deficient TcdB demonstrated no toxicity up to 500-fold of the 50% lethal dose (LD50) when it was injected systemically. Thus, glucosyltransferase but not cysteine protease activity is critical for TcdB-mediated cytopathic effects and TcdB systemic toxicity, highlighting the importance of targeting toxin glucosyltransferase activity for future therapy.

STEM-15. SerpinB3 DRIVES CANCER STEM CELL SURVIVAL IN GLIOBLASTOMA

2021 ◽  
Vol 23 (Supplement_6) ◽  
pp. vi24-vi24
Author(s):  
Adam Lauko ◽  
Soumya M Turaga ◽  
Josephine Volovetz ◽  
Defne Bayik ◽  
Shideng Bao ◽  
...  
Keyword(s):  
Cell Death ◽  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Xenograft Model ◽  
Standard Of Care ◽  
Therapeutic Interventions ◽  
Cysteine Protease Inhibitor ◽  
Orthotopic Xenograft Model

Abstract Despite therapeutic interventions for glioblastoma (GBM), self-renewing, therapy-resistant populations of cells referred to as cancer stem cells (CSCs) drive recurrence. Previously, we identified the unique expression of junctional adhesion molecule-A (JAM-A) on CSCs and demonstrated that JAM-A is both necessary and sufficient for self-renewal and tumor growth. Moreover, we determined that JAM-A signals via Akt in GBM CSCs to sustain pluripotency transcription factor activity; however, the entire signaling network has yet to be fully elucidated. To further delineate this pathway, we immunoprecipitated JAM-A from patient-derived GBM CSCs and performed mass spectrometry to determine JAM-A binding proteins. This led to the identification of the cysteine protease inhibitor SerpinB3 as a putative JAM-A binding partner. Using in vitro CSC functional assays, we show that SerpinB3 is necessary for CSC maintenance and survival. In an in vivo orthotopic xenograft model, knockdown of SerpinB3 extended survival. Mechanistically, knockdown of SerpinB3 led to decreased expression of TGF-β, Myc, WNT, and Notch signaling, known regulators of the CSC state. Additionally, knockdown of SerpinB3 increases susceptibility to radiation therapy. SerpinB3 is essential for buffering cells against cathepsin-mediated cell death, and we found that elevated lysosomal membrane permeability after radiation leads to cathepsin release into the cytoplasm. As a result, SerpinB3 knockdown cells have a diminished capacity to inhibit cathepsin-driven cell death after radiation. The addition of the cathepsin inhibitor E64D partially rescues the SerpinB3 knockdown, however, SerpinB3 mutants that are unable to inhibit cathepsins fail to do the same. Taken together, our findings, identify a novel GBM CSC-specific survival mechanism involving a previously uninvestigated cysteine protease inhibitor, SerpinB3, and provide a potential target to increase the efficacy of standard of care GBM therapies against therapy-resistant CSCs.

Engineering and functional evaluation of neutralizing antibody fragments against congenital toxoplasmosis

2021 ◽  
Author(s):  
Anne di Tommaso ◽  
Matthieu O Juste ◽  
Zineb Lakhrif ◽  
Marie-Noëlle Mévélec ◽  
Coraline Borowczyk ◽  
...  
Keyword(s):  
Specific Treatment ◽  
Congenital Toxoplasmosis ◽  
Surface Protein ◽  
Neutralizing Antibody ◽  
Antibody Fragments ◽  
Functional Evaluation ◽  
Maternal Fetal Transmission ◽  
Major Surface

Abstract Maternal-fetal transmission of Toxoplasma gondii tachyzoites acquired during pregnancy has potentially dramatic consequences for the fetus. Current gold-standard treatments are not specific to the parasite and can induce severe side effects. In order to provide treatments with a higher specificity against toxoplasmosis, we developed antibody fragments – scFv, scFv-Fc – directed against the major surface protein SAG1. After validating their capacity to inhibit T. gondii proliferation in vitro, the antibody fragments’ biological activity was assessed in vivo using a congenital toxoplasmosis mouse model. Dams were treated by systemic administration of antibody fragments and with prevention of maternal-fetal transmission being used as the parameter of efficacy. We observed that both antibody fragments prevented T. gondii dissemination and protected neonates, with the scFv-Fc format having a better efficacy. These data provide a proof-of-concept for the use of antibody fragments as effective and specific treatment against congenital toxoplasmosis and provide promising leads.

scholarly journals Nippocystatin, a Cysteine Protease Inhibitor fromNippostrongylus brasiliensis, Inhibits Antigen Processing and Modulates Antigen-Specific Immune Response

2001 ◽  
Vol 69 (12) ◽  
pp. 7380-7386 ◽  
Author(s):  
Teruki Dainichi ◽  
Yoichi Maekawa ◽  
Kazunari Ishii ◽  
Tianqian Zhang ◽  
Baher Fawzy Nashed ◽  
...  
Keyword(s):  
Immune System ◽  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Antigen Processing ◽  
Cysteine Proteases ◽  
Cysteine Protease Inhibitor ◽  
Host Immune System ◽  
Nippostrongylus Brasiliensis

ABSTRACT During infection, parasites evade the host immune system by modulating or exploiting the immune system; e.g., they suppress expression of major histocompatibility complex class II molecules or secrete cytokine-like molecules. However, it is not clear whether helminths disturb the immune responses of their hosts by controlling the antigen-processing pathways of the hosts. In this study, we identified a new cysteine protease inhibitor, nippocystatin, derived from excretory-secretory (ES) products of an intestinal nematode,Nippostrongylus brasiliensis. Nippocystatin, which belongs to cystatin family 2, consists of 144 amino acids and is secreted as a 14-kDa mature form. In vivo treatment of ovalbumin (OVA)-immunized mice with recombinant nippocystatin (rNbCys) profoundly suppressed OVA-specific proliferation of splenocytes but not non-antigen-specific proliferation of splenocytes. OVA-specific cytokine production was also greatly suppressed in rNbCys-treated mice. Although the serum levels of both OVA-specific immunoglobulin G1 (IgG1) and IgG2a were not affected by rNbCys treatment, OVA-specific IgE was preferentially downregulated in rNbCys-treated mice. In vitro rNbCys inhibited processing of OVA by lysosomal cysteine proteases from the spleens of mice. Mice with anti-nippocystatin antibodies became partially resistant to infection with N. brasiliensis. Based on these findings, N. brasiliensis appears to skillfully evade host immune systems by secreting nippocystatin, which modulates antigen processing in antigen-presenting cells of hosts.

scholarly journals Antimalarial Activity of Allicin, a Biologically Active Compound from Garlic Cloves

2006 ◽  
Vol 50 (5) ◽  
pp. 1731-1737 ◽  
Author(s):  
Alida Coppi ◽  
Melissa Cabinian ◽  
David Mirelman ◽  
Photini Sinnis
Keyword(s):  
Life Cycle ◽  
Protease Inhibitor ◽  
Cysteine Protease ◽  
Malaria Infection ◽  
Drug Targets ◽  
Host Cells ◽  
Cysteine Protease Inhibitor ◽  
New Drug

ABSTRACT The incidence of malaria is increasing, and there is an urgent need to identify new drug targets for both prophylaxis and chemotherapy. Potential new drug targets include Plasmodium proteases that play critical roles in the parasite life cycle. We have previously shown that the major surface protein of Plasmodium sporozoites, the circumsporozoite protein (CSP), is proteolytically processed by a parasite-derived cysteine protease, and this processing event is temporally associated with sporozoite invasion of host cells. E-64, a cysteine protease inhibitor, inhibits CSP processing and prevents invasion of host cells in vitro and in vivo. Here we tested allicin, a cysteine protease inhibitor found in garlic extracts, for its ability to inhibit malaria infection. At low concentrations, allicin was not toxic to either sporozoites or mammalian cells. At these concentrations, allicin inhibited CSP processing and prevented sporozoite invasion of host cells in vitro. In vivo, mice injected with allicin had decreased Plasmodium infections compared to controls. When sporozoites were treated with allicin before injection into mice, malaria infection was completely prevented. We also tested allicin on erythrocytic stages and found that a 4-day regimen of allicin administered either orally or intravenously significantly decreased parasitemias and increased the survival of infected mice by 10 days. Together, these experiments demonstrate that the same cysteine protease inhibitor can target two different life cycle stages in the vertebrate host.

Non-Viral Vectors for Gene Delivery

2018 ◽  
Vol 9 (1) ◽  
pp. 4-11 ◽  
Author(s):  
Aparna Bansal ◽  
Himanshu
Keyword(s):  
Gene Therapy ◽  
Viral Vectors ◽  
Transfection Efficiency ◽  
Gene Transfection ◽  
Expression System ◽  
Target Cells ◽  
Specific Expression ◽  
Naked Dna

Introduction: Gene therapy has emerged out as a promising therapeutic pave for the treatment of genetic and acquired diseases. Gene transfection into target cells using naked DNA is a simple and safe approach which has been further improved by combining vectors or gene carriers. Both viral and non-viral approaches have achieved a milestone to establish this technique, but non-viral approaches have attained a significant attention because of their favourable properties like less immunotoxicity and biosafety, easy to produce with versatile surface modifications, etc. Literature is rich in evidences which revealed that undoubtedly, non–viral vectors have acquired a unique place in gene therapy but still there are number of challenges which are to be overcome to increase their effectiveness and prove them ideal gene vectors. Conclusion: To date, tissue specific expression, long lasting gene expression system, enhanced gene transfection efficiency has been achieved with improvement in delivery methods using non-viral vectors. This review mainly summarizes the various physical and chemical methods for gene transfer in vitro and in vivo.

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