scholarly journals Identification of host tRNAs preferentially recognized by the Plasmodium surface protein tRip

2021 ◽  
Vol 49 (18) ◽  
pp. 10618-10629
Author(s):  
Marta Cela ◽  
Anne Théobald-Dietrich ◽  
Joëlle Rudinger-Thirion ◽  
Philippe Wolff ◽  
Renaud Geslain ◽  
...  
Keyword(s):  
Homo Sapiens ◽  
Protein A ◽  
Surface Protein ◽  
Structural Motif ◽  
Parasite Development ◽  
Small Subset ◽  
Wide Range ◽  
Life Threatening ◽  
Host Parasite

Abstract Malaria is a life-threatening and devastating parasitic disease. Our previous work showed that parasite development requires the import of exogenous transfer RNAs (tRNAs), which represents a novel and unique form of host–pathogen interaction, as well as a potentially druggable target. This import is mediated by tRip (tRNA import protein), a membrane protein located on the parasite surface. tRip displays an extracellular domain homologous to the well-characterized OB-fold tRNA-binding domain, a structural motif known to indiscriminately interact with tRNAs. We used MIST (Microarray Identification of Shifted tRNAs), a previously established in vitro approach, to systematically assess the specificity of complexes between native Homo sapiens tRNAs and recombinant Plasmodium falciparum tRip. We demonstrate that tRip unexpectedly binds to host tRNAs with a wide range of affinities, suggesting that only a small subset of human tRNAs is preferentially imported into the parasite. In particular, we show with in vitro transcribed constructs that tRip does not bind specific tRNAs solely based on their primary sequence, hinting that post-transcriptional modifications modulate the formation of our host/parasite molecular complex. Finally, we discuss the potential utilization of the most efficient tRip ligands for the translation of the parasite's genetic information.

scholarly journals Bacterial Immunoglobulin Superantigen Proteins A and L Activate Human Heart Mast Cells by Interacting with Immunoglobulin E

2000 ◽  
Vol 68 (10) ◽  
pp. 5517-5524 ◽  
Author(s):  
Arturo Genovese ◽  
Jean-Pierre Bouvet ◽  
Giovanni Florio ◽  
Bärbel Lamparter-Schummert ◽  
Lars Björck ◽  
...  
Keyword(s):  
Mast Cells ◽  
Human Heart ◽  
Immunoglobulin E ◽  
Protein A ◽  
Surface Protein ◽  
Heart Tissue ◽  
Protein L ◽  
Cysteinyl Leukotriene ◽  
Proinflammatory Mediators

ABSTRACT Human heart mast cells (HHMC) have been identified in heart tissue, perivascularly, and in the intima of coronary arteries. In vitro activation of isolated HHMC induces the release of vasoactive and proinflammatory mediators (histamine, tryptase, and cysteinyl leukotriene C4 [LTC4]). We investigated the effects of several bacterial proteins on HHMC activation in vitro. HHMC released histamine, tryptase, and LTC4 in response toStaphylococcus aureus Cowan 1 and the immunoglobulin (Ig)-binding protein A, but not to S. aureus Wood 46, which does not synthesize protein A. The effect of protein A was inhibited by preincubation with monoclonal IgM VH3+. Some strains of Peptostreptococcus magnus express an Ig light chain-binding surface protein called protein L. Such bacteria and soluble protein L stimulated the release of preformed and newly synthesized mediators from HHMC. Preincubation of HHMC with either protein A or protein L resulted in complete cross-desensitization to a subsequent challenge with the heterologous stimulus or anti-IgE. Monoclonal IgE (κ chains) blocked protein L-induced release, whereas IgE (λ chains) had no effect. Streptococcal protein G, formyl-containing tripeptide, and pepstatin A did not activate HHMC. Bacterial products protein A and protein L and intact bacteria (S. aureus and P. magnus) activate HHMC by acting as Ig superantigens.

scholarly journals Analysis of Plasmodium vivax schizont transcriptomes from field isolates reveals heterogeneity of expression of genes involved in host-parasite interactions

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Sasha V. Siegel ◽  
Lia Chappell ◽  
Jessica B. Hostetler ◽  
Chanaki Amaratunga ◽  
Seila Suon ◽  
...  
Keyword(s):  
Plasmodium Vivax ◽  
Ex Vivo ◽  
Culture Method ◽  
Surface Proteins ◽  
Parasite Development ◽  
Field Isolates ◽  
Host Parasite Interactions ◽  
Short Period ◽  
Host Parasite

Abstract Plasmodium vivax gene regulation remains difficult to study due to the lack of a robust in vitro culture method, low parasite densities in peripheral circulation and asynchronous parasite development. We adapted an RNA-seq protocol “DAFT-seq” to sequence the transcriptome of four P. vivax field isolates that were cultured for a short period ex vivo before using a density gradient for schizont enrichment. Transcription was detected from 78% of the PvP01 reference genome, despite being schizont-enriched samples. This extensive data was used to define thousands of 5′ and 3′ untranslated regions, some of which overlapped with neighbouring transcripts, and to improve the gene models of 352 genes, including identifying 20 novel gene transcripts. This dataset has also significantly increased the known amount of heterogeneity between P. vivax schizont transcriptomes from individual patients. The majority of genes found to be differentially expressed between the isolates lack Plasmodium falciparum homologs and are predicted to be involved in host-parasite interactions, with an enrichment in reticulocyte binding proteins, merozoite surface proteins and exported proteins with unknown function. An improved understanding of the diversity within P. vivax transcriptomes will be essential for the prioritisation of novel vaccine targets.

scholarly journals Borrelia burgdorferi Escape Mutants That Survive in the Presence of Antiserum to the OspA Vaccine Are Killed When Complement Is Also Present

1998 ◽  
Vol 66 (6) ◽  
pp. 2540-2546 ◽  
Author(s):  
Mónica Solé ◽  
Carlos Bantar ◽  
Karl Indest ◽  
Yan Gu ◽  
Ramesh Ramamoorthy ◽  
...  
Keyword(s):  
Borrelia Burgdorferi ◽  
Protein A ◽  
Surface Protein ◽  
Sensu Stricto ◽  
Antibody Concentration ◽  
Initial Attempt ◽  
Outer Surface Protein A ◽  
Escape Mutants ◽  
Low Passage

ABSTRACT As an initial attempt to investigate the possible role of outer surface protein A (OspA) escape mutants of Borrelia burgdorferi in decreasing the efficacy of the OspA vaccine, mutants of the HB19 strain of B. burgdorferi sensu stricto were selected in vitro from an uncloned, low-passage-number isolate. The antiserum used for selection was obtained from rhesus monkeys that had been given a vaccine of the same formulation and dose, and by the same route of administration, as that given to humans in several trials. All of the mutants selected in liquid medium and subsequently cloned twice in solid medium expressed a single abundant protein of 28 to 34 kDa instead of both OspA and OspB. Depending on the mutant, this protein reacted strongly, weakly, or not detectably with the anti-OspA antibody used for selection. Analysis of the ospAB locus of each of four representatives from these three groups of mutants by PCR with oligonucleotide primers that hybridize to flanking regions of theospAB operon, and of the corresponding phenotype with monoclonal antibodies that bind to the amino or carboxyl terminus of the OspA or OspB polypeptide, indicated that in all cases a deletion within the operon had occurred. Spirochetes from the four mutant strains chosen for further analysis could be killed in antibody-dependent, complement-mediated killing assays with the selecting anti-OspA antibody, despite their resistance to killing with this antibody in the absence of complement. Complement-mediated killing occurred at an antibody concentration higher than that required to kill wild-type spirochetes. If anti-OspA antibody acts only within the tick, where complement is probably ineffective due to tick-derived decomplementing factors, then OspA escape mutants, if infectious, could seriously diminish the efficacy of OspA vaccines. On the other hand, if the killing of B. burgdorferi with anti-OspA antibody also takes place within the human host, then our results indicate that chimeric/deletion escape mutants will be killed as well.

scholarly journals CLIPB10 is a Terminal Protease in the Regulatory Network That Controls Melanization in the African Malaria Mosquito Anopheles gambiae

2021 ◽  
Vol 10 ◽  
Author(s):  
Xin Zhang ◽  
Miao Li ◽  
Layla El Moussawi ◽  
Sally Saab ◽  
Shasha Zhang ◽  
...  
Keyword(s):  
Anopheles Gambiae ◽  
Serine Proteases ◽  
Ex Vivo ◽  
Protein A ◽  
Tumor Formation ◽  
Sub Saharan Africa ◽  
Humoral Immune ◽  
Wide Range ◽  
Sub Saharan

Humoral immune responses in animals are often tightly controlled by regulated proteolysis. This proteolysis is exerted by extracellular protease cascades, whose activation culminates in the proteolytic cleavage of key immune proteins and enzymes. A model for such immune system regulation is the melanization reaction in insects, where the activation of prophenoxidase (proPO) leads to the rapid formation of eumelanin on the surface of foreign entities such as parasites, bacteria and fungi. ProPO activation is tightly regulated by a network of so-called clip domain serine proteases, their proteolytically inactive homologs, and their serpin inhibitors. In Anopheles gambiae, the major malaria vector in sub-Saharan Africa, manipulation of this protease network affects resistance to a wide range of microorganisms, as well as host survival. However, thus far, our understanding of the molecular make-up and regulation of the protease network in mosquitoes is limited. Here, we report the function of the clip domain serine protease CLIPB10 in this network, using a combination of genetic and biochemical assays. CLIPB10 knockdown partially reversed melanotic tumor formation induced by Serpin 2 silencing in the absence of infection. CLIPB10 was also partially required for the melanization of ookinete stages of the rodent malaria parasite Plasmodium berghei in a refractory mosquito genetic background. Recombinant serpin 2 protein, a key inhibitor of the proPO activation cascade in An. gambiae, formed a SDS-stable protein complex with activated recombinant CLIPB10, and efficiently inhibited CLIPB10 activity in vitro at a stoichiometry of 1.89:1. Recombinant activated CLIPB10 increased PO activity in Manduca sexta hemolymph ex vivo, and directly activated purified M. sexta proPO in vitro. Taken together, these data identify CLIPB10 as the second protease with prophenoloxidase-activating function in An. gambiae, in addition to the previously described CLIPB9, suggesting functional redundancy in the protease network that controls melanization. In addition, our data suggest that tissue melanization and humoral melanization of parasites are at least partially mediated by the same proteases.

scholarly journals A common TMPRSS2 variant protects against severe COVID-19

2021 ◽  
Author(s):  
Alessia David ◽  
Nicholas Parkinson ◽  
Thomas P Peacock ◽  
Erola Pairo-Castineira ◽  
Tarun Khanna ◽  
...  
Keyword(s):  
Large Population ◽  
Age Groups ◽  
Target Cells ◽  
Type I ◽  
Type I Ifns ◽  
Postoperative Reflux ◽  
Wide Range ◽  
Life Threatening ◽  
A Minor

SummaryInfection with SARS-CoV-2 has a wide range of clinical presentations, from asymptomatic to life-threatening. Old age is the strongest factor associated with increased COVID19-related mortality, followed by sex and pre-existing conditions. The importance of genetic and immunological factors on COVID19 outcome is also starting to emerge, as demonstrated by population studies and the discovery of damaging variants in genes controlling type I IFN immunity and of autoantibodies that neutralize type I IFNs. The human protein transmembrane protease serine type 2 (TMPRSS2) plays a key role in SARS-CoV-2 infection, as it is required to activate the virus’ spike protein, facilitating entry into target cells. We focused on the only common TMPRSS2 non-synonymous variant predicted to be damaging (rs12329760), which has a minor allele frequency of ∼25% in the population. In a large population of SARS-CoV-2 positive patients, we show that this variant is associated with a reduced likelihood of developing severe COVID19 (OR 0.87, 95%CI:0.79-0.97, p=0.01). This association was stronger in homozygous individuals when compared to the general population (OR 0.65, 95%CI:0.50-0.84, p=1.3×10−3). We demonstrate in vitro that this variant, which causes the amino acid substitution valine to methionine, impacts the catalytic activity of TMPRSS2 and is less able to support SARS-CoV-2 spike-mediated entry into cells.TMPRSS2 rs12329760 is a common variant associated with a significantly decreased risk of severe COVID19. Further studies are needed to assess the expression of the TMPRSS2 across different age groups. Moreover, our results identify TMPRSS2 as a promising drug target, with a potential role for camostat mesilate, a drug approved for the treatment of chronic pancreatitis and postoperative reflux esophagitis, in the treatment of COVID19. Clinical trials are needed to confirm this.

scholarly journals Antimicrobial activity of Tachyplesin 1 againstBurkholderia pseudomallei: an in vitro and in silico approach

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e2468 ◽  
Author(s):  
Lyn-Fay Lee ◽  
Vanitha Mariappan ◽  
Kumutha Malar Vellasamy ◽  
Vannajan Sanghiran Lee ◽  
Jamuna Vadivelu
Keyword(s):  
In Silico ◽  
Antimicrobial Agents ◽  
Protein A ◽  
Surface Protein ◽  
In Vitro Study ◽  
Planktonic Cell ◽  
Mammalian Cell Lines ◽  
Electrostatic Contribution ◽  
Conventional Antibiotics

Burkholderia pseudomallei, the causative agent of melioidosis, is intrinsically resistant to many conventional antibiotics. Therefore, alternative antimicrobial agents such as antimicrobial peptides (AMPs) are extensively studied to combat this issue. Our study aims to identify and understand the mode of action of the potential AMP(s) that are effective againstB. pseudomalleiin both planktonic and biofilm state as well as to predict the possible binding targets on using in vitro and in silico approaches. In the in vitro study, 11 AMPs were tested against 100B. pseudomalleiisolates for planktonic cell susceptibility, where LL-37, and PG1, demonstrated 100.0% susceptibility and TP1 demonstrated 83% susceptibility. Since theB. pseudomalleiactivity was reported on LL-37 and PG1, TP1 was selected for further investigation. TP1 inhibitedB. pseudomalleicells at 61.69 μM, and membrane blebbing was observed using scanning electron microscopy. Moreover, TP1 inhibitedB. pseudomalleicell growth, reaching bactericidal endpoint within 2 h post exposure as compared to ceftazidime (CAZ) (8 h). Furthermore, TP1 was shown to suppress the growth ofB. pseudomalleicells in biofilm state at concentrations above 221 μM. However, TP1 was cytotoxic to the mammalian cell lines tested. In the in silico study, molecular docking revealed that TP1 demonstrated a strong interaction to the common peptide or inhibitor binding targets for lipopolysaccharide ofEscherichia coli, as well as autolysin, pneumolysin, and pneumococcal surface protein A (PspA) ofStreptococcus pneumoniae. Homology modelledB. pseudomalleiPspA protein (YDP) also showed a favourable binding with a strong electrostatic contribution and nine hydrogen bonds. In conclusion, TP1 demonstrated a good potential as an anti-B. pseudomalleiagent.

scholarly journals Analysis of Human Faecal Host Proteins: Responsiveness to 10-Week Dietary Intervention Modifying Dietary Protein Intake in Elderly Males

2021 ◽  
Vol 7 ◽  
Author(s):  
Jessica L. Gathercole ◽  
Anita J. Grosvenor ◽  
Erin Lee ◽  
Ancy Thomas ◽  
Cameron J. Mitchell ◽  
...  
Keyword(s):  
Dietary Protein ◽  
Protein Intake ◽  
Dietary Intervention ◽  
Homo Sapiens ◽  
Dietary Factors ◽  
Small Subset ◽  
Host Proteins ◽  
Minimal Impact ◽  
Wide Range ◽  
Protein Classes

Faecal proteomics targeting biomarkers of immunity and inflammation have demonstrated clinical application for the identification of changes in gastrointestinal function. However, there are limited comprehensive analyses of the host faecal proteome and how it may be influenced by dietary factors. To examine this, the Homo sapiens post-diet proteome of older males was analysed at the completion of a 10-week dietary intervention, either meeting the minimum dietary protein recommendations (RDA; n = 9) or twice the recommended dietary allowance (2RDA, n = 10). The host faecal proteome differed markedly between individuals, with only a small subset of proteins present in ≥ 60% of subjects (14 and 44 proteins, RDA and 2RDA, respectively, with only 7 common to both groups). No differences were observed between the diet groups on the profiles of host faecal proteins. Faecal proteins were detected from a wide range of protein classes, with high inter-individual variation and absence of obvious impact in response to diets with markedly different protein intake. This suggests that well-matched whole food diets with two-fold variation in protein intake maintained for 10 weeks have minimal impact on human faecal host proteins.

scholarly journals Dual roles of a novel oncolytic viral vector-based SARS-CoV-2 vaccine: preventing COVID-19 and treating tumor progression

2021 ◽  
Author(s):  
Michael A. Caligiuri ◽  
Jianhua Yu ◽  
Yaping Sun ◽  
Wenjuan Dong ◽  
Lei Tian ◽  
...  
Keyword(s):  
Cancer Patients ◽  
Viral Vector ◽  
Protein A ◽  
Surface Protein ◽  
T Cell Response ◽  
Host Cells ◽  
Serious Adverse Events ◽  
S Protein ◽  
Tumor Bearing

The ongoing coronavirus disease 2019 (COVID-19) pandemic is caused by infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Cancer patients are usually immunocompromised and thus are particularly susceptible to SARS-CoV-2 infection resulting in COVID-19. Although many vaccines against COVID-19 are being preclinically or clinically tested or approved, none have yet been specifically developed for cancer patients or reported as having potential dual functions to prevent COVID-19 and treat cancer. Here, we confirmed that COVID-19 patients with cancer have low levels of antibodies against the spike (S) protein, a viral surface protein mediating the entry of SARS-CoV-2 into host cells, compared with COVID-19 patients without cancer. We developed an oncolytic herpes simplex virus-1 vector-based vaccine named oncolytic virus (OV)-spike. OV-spike induced abundant anti-S protein neutralization antibodies in both tumor-free and tumor-bearing mice, which inhibit infection of VSV-SARS-CoV-2 and wild-type (WT) live SARS-CoV-2 as well as the B.1.1.7 variant in vitro. In the tumor-bearing mice, OV-spike also inhibited tumor growth, leading to better survival in multiple preclinical tumor models than the untreated control. Furthermore, OV-spike induced anti-tumor immune response and SARS-CoV-2-specific T cell response without causing serious adverse events. Thus, OV-spike is a promising vaccine candidate for both preventing COVID-19 and enhancing the anti-tumor response.

scholarly journals Homologue of Macrophage-Activating Lipoprotein in Mycoplasmagallisepticum Is Not Essential for Growth and Pathogenicity in Tracheal Organ Cultures

2003 ◽  
Vol 185 (8) ◽  
pp. 2538-2547 ◽  
Author(s):  
Philip F. Markham ◽  
Anna Kanci ◽  
György Czifra ◽  
Bo Sundquist ◽  
Peter Hains ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Tetracycline Resistance ◽  
Surface Protein ◽  
Enzyme Linked Immunosorbent Assay ◽  
Homologous Gene ◽  
Organ Cultures ◽  
Western Blots ◽  
Wide Range ◽  
The Difference

ABSTRACT While the genomes of a number of Mycoplasma species have been fully determined, there has been limited characterization of which genes are essential. The surface protein (p47) identified by monoclonal antibody B3 is the basis for an enzyme-linked immunosorbent assay for serological detection of Mycoplasma gallisepticum infection and appears to be constitutively expressed. Its gene was cloned, and the DNA sequence was determined. Subsequent analysis of the p47 amino acid sequence and searches of DNA databases found homologous gene sequences in the genomes of M. pneumoniae and M. genitalium and identity with a gene family in Ureaplasma urealyticum and genes in M. agalactiae and M. fermentans. The proteins encoded by these genes were found to belong to a family of basic membrane proteins (BMP) that are found in a wide range of bacteria, including a number of pathogens. Several of the BMP family members, including p47, contain selective lipoprotein-associated motifs that are found in macrophage-activating lipoprotein 404 of M. fermentans and lipoprotein P48 of M. agalactiae. The p47 gene was predicted to encode a 59-kDa peptide, but affinity-purified p47 had a molecular mass of approximately 47 kDa, as determined by polyacrylamide gel analysis. Analysis of native and recombinant p47 by mass peptide fingerprinting revealed the absence of the carboxyl end of the protein encoded by the p47 gene in native p47, which would account for the difference seen in the predicted and measured molecular weights and indicated posttranslational cleavage of the lipoprotein at its carboxyl end. A DNA construct containing the p47 gene interrupted by the gene encoding tetracycline resistance was used to transform M. gallisepticum cells. A tetracycline-resistant mycoplasma clone, P2, contained the construct inserted within the genomic p47 gene, with crossovers occurring between 73 bp upstream and 304 bp downstream of the inserted tetracycline resistance gene. The absence of p47 protein in clone P2 was determined by the lack of reactivity with rabbit anti-p47 sera or monoclonal antibody B3 in Western blots of whole-cell proteins. There was no difference between the p47− mutant and wild-type M. gallisepticum in pathogenicity in chicken tracheal organ cultures. Thus, p47, although homologous to genes that occur in many prokaryotes, is not essential for growth in vitro or for attachment and the initial stages of pathogenesis in chickens.

scholarly journals PneumococcalSurface Protein A Is Expressed In Vivo, and Antibodies to PspA AreEffective for Therapy in a Murine Model of PneumococcalSepsis

2003 ◽  
Vol 71 (12) ◽  
pp. 7149-7153 ◽  
Author(s):  
E. Swiatlo ◽  
J. King ◽  
G. S. Nabors ◽  
B. Mathews ◽  
D. E. Briles
Keyword(s):  
Northern Blot Analysis ◽  
Lethal Dose ◽  
Protein A ◽  
Surface Protein ◽  
Immune Serum ◽  
Invasive Infection ◽  
Pneumococcal Infections ◽  
Type 3

ABSTRACT Pneumococcal surface protein A (PspA) is an immunogenic protein expressed on the surface of all strains of Streptococcus pneumoniae (pneumococcus) and induces antibodies which protect against invasive infection in mice. Pneumococci used for infectious challenge in protection studies are typically collected from cultures grown in semisynthetic medium in vitro. The purpose of these studies is to confirm that PspA is expressed by pneumococci during growth in vivo at a level sufficient for antibodies to PspA to be protective. Mice were actively immunized with purified PspA or by passive transfer of monoclonal antibody (MAb) and challenged with a capsular type 3 strain in diluted whole blood from bacteremic mice. All were protected against challenge with 10 times the 50% lethal dose (LD50), and mice challenged with 1,000 times the LD50 had increased survival compared with controls. Additionally, nonimmune mice treated with MAbs to PspA or PspA immune serum at 6 and 12 h after infection with 10 times the LD50 also showed increased survival. Northern blot analysis of RNA from pneumococci grown either in vitro or in vivo showed similar levels of PspA mRNA. These results demonstrate that PspA is expressed in vivo in a mouse model and that immunization with PspA induces antibodies to an antigen which is expressed during the course of invasive infection. Immunotherapy with antibodies to PspA may have some utility in treating pneumococcal infections in humans.

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