scholarly journals Comediation of Erythrocyte Haemolysis by Erythrocyte-Derived Microparticles and Complement during Malaria Infection

2020 ◽  
Vol 2020 ◽  
pp. 1-5
Author(s):  
Ransford Kyeremeh ◽  
Samuel Antwi-Baffour ◽  
Max Annani-Akollor ◽  
Jonathan Kofi Adjei ◽  
Otchere Addai-Mensah ◽  
...  
Keyword(s):  
Malaria Infection ◽  
Surface Protein ◽  
Surface Proteins ◽  
Sub Saharan Africa ◽  
In Vitro Assays ◽  
Intracellular Location ◽  
Fixed Volume ◽  
Global Threat ◽  
Erythrocyte Haemolysis

Background. Due to the sustained morbidity and mortality that malaria-associated anaemia imposes on patients, malaria is still a global threat, most especially, to residents in sub-Saharan Africa. Merozoite invasion and destruction of erythrocytes, a target for this study, have been necessary due to its unique nature and also since the erythrocytes suffer the most brunt of malarial infection leading to anaemia. The issue of malaria anaemia has to do with why uninfected RBCs get destroyed and even more so than infected ones. Studies have proposed that cytophilic anti-RSP2 (ring surface protein 2—merozoite rhoptry protein 2) antibodies present in sera enhance phagocytosis of RSP2-tagged RBCs by macrophages either directly or via complement, while others have proposed transfer of RSP2 to both infected and uninfected RBCs which may render them susceptible to phagocytosis. What is missing is the agent involved in the transfer of these parasite-induced surface proteins onto the uninfected RBCs, i.e., the mediator molecules. Considering the intracellular location of the parasite in the parasitophorous vacuolar membrane and the absence of a transport mechanism such as the Golgi apparatus within the mature RBC, since the latter has no nucleus, we propose that erythrocyte-derived microparticles (EMPs) may be the possible mediators. Aim. This study aimed at examining the immunological interactions between EMPs released during malarial infections and host erythrocytes that may lead to their lysis possibly through complement mediation. Methods. This was an experimental study during which malarial EMPs were isolated by differential centrifugation of malaria-positive plasma. This was followed by cell-based in vitro assays where malaria-positive EMPs were added to uninfected blood group “O” negative erythrocytes in the presence of complement and haemolysis checked for. Results and Conclusion. At a fixed volume of 50 μL complement, there were statistically significant (p<0.01) increases in mean percentage haemolysis as the volume of EMPs increased. Similarly, at a fixed volume of 50 μL EMPs, there were statistically significant (p<0.01) increases in mean percentage haemolysis with increasing volumes of complement. This was an indication that both complement and EMPs contribute significantly to uninfected erythrocyte haemolysis during malaria infection.

scholarly journals A genomic and proteomic analysis of surface proteins in bovine-adapted lineages of Staphylococcus aureus

2020 ◽  
Vol 2 (7A) ◽  
Author(s):  
Shauna D. Drumm ◽  
Rebecca Owens ◽  
Jennifer Mitchell ◽  
Orla M. Keane
Keyword(s):  
Staphylococcus Aureus ◽  
Cell Wall ◽  
Surface Proteins ◽  
Host Cells ◽  
Mass Spectrometry Analysis ◽  
In Vitro Assays ◽  
Immune Recognition ◽  
Independent Manner ◽  
Genes Encoding

In Ireland, Staphylococcus aureus is the most common cause of intramammary infection (IMI) in cattle with the bovine-adapted lineages CC151 and CC97 most commonly found. Surface proteins play a major role in establishing and maintaining the infection. A previous study revealed that a strain from the CC151 lineage showed significant decay in genes encoding predicted surface proteins. Twenty-three S. aureus strains, twelve belonging to CC151 and eleven belonging to CC97, isolated from clinical IMI, were sequenced and genes encoding cell wall anchored (CWA) proteins predicted. Analysis showed that a minority of genes encoding putative CWA proteins were intact in the CC151 strains compared to CC97. Of the 26 known CWA proteins in S. aureus, the CC151 strains only encoded 10 intact genes while CC97 encoded on average 18 genes. Also within the CC97 lineage, the repertoire of genes varied depending on individual strains, with strains encoding between 17-20 intact genes. Although CC151 is reported to internalize within bovine host cells, it does so in a fibronectin-binding protein (FnBPA and FnBPB) independent manner. In-vitro assays were performed and results showed that strains from CC151, and surprisingly also CC97, weakly bound bovine fibronectin and that the FnBPs were poorly expressed in both these lineages. Mass spectrometry analysis of cell wall extracts revealed that SdrE and AdsA were the most highly expressed CWA proteins in both lineages. These results demonstrate significant differences between CC151 and CC97 in their repertoire of genes encoding CWA proteins, which may impact immune recognition of these strains and their interactions with host cells.

scholarly journals Impaired Hematopoiesis in Paroxysmal Nocturnal Hemoglobinuria/Aplastic Anemia Is Not Associated With a Selective Proliferative Defect in the Glycosylphosphatidylinositol-Anchored Protein-Deficient Clone

Blood ◽  
1997 ◽  
Vol 89 (4) ◽  
pp. 1173-1181 ◽  
Author(s):  
Jaroslaw P. Maciejewski ◽  
Elaine M. Sloand ◽  
Tadatsugu Sato ◽  
Stacie Anderson ◽  
Neal S. Young
Keyword(s):  
Protein Expression ◽  
Aplastic Anemia ◽  
Paroxysmal Nocturnal Hemoglobinuria ◽  
Surface Proteins ◽  
In Vitro Assays ◽  
Normal Numbers ◽  
Normal Volunteers ◽  
Cd34 Cells ◽  
Cd59 Expression

Abstract Paroxysmal nocturnal hemoglobinuria (PNH) results from somatic mutations in the PIG-A gene, leading to poor presentation of glycosylphosphatidylinositol (GPI)-anchored surface proteins. PNH frequently occurs in association with suppressed hematopoiesis, including frank aplastic anemia (AA). The relationship between GPI-anchored protein expression and bone marrow (BM) failure is unknown. To assess the hematopoietic defect in PNH, the numbers of CD34+ cells, committed progenitors (primary colony-forming cells [CFCs]), and long-term culture-initiating cells (LTC-ICs; a stem cell surrogate) were measured in BM and peripheral blood (PB) of patients with PNH/AA syndrome or patients with predominantly hemolytic PNH. LTC-IC numbers were extrapolated from secondary CFC numbers after 5 weeks of culture, and clonogenicity of LTC-ICs was determined by limiting dilution assays. When compared with normal volunteers (n = 13), PNH patients (n = 14) showed a 4.7-fold decrease in CD34+ cells and an 8.2-fold decrease in CFCs. LTC-ICs in BM and in PB were decreased 7.3-fold and 50-fold, respectively. Purified CD34+ cells from PNH patients had markedly lower clonogenicity in both primary colony cultures and in the LTC-IC assays. As expected, GPI-anchored proteins were decreased on PB cells of PNH patients. On average, 23% of monocytes were deficient in CD14, and 47% of granulocytes and 58% of platelets lacked CD16 and CD55, respectively. In PNH BM, 27% of CD34+ cells showed abnormal GPI-anchored protein expression when assessed by CD59 expression. To directly measure the colony-forming ability of GPI-anchored protein-deficient CD34+ cells, we separated CD34+ cells from PNH patients for the GPI+ and GPI− phenotype; CD59 expression was chosen as a marker of the PNH phenotype based on high and homogeneous expression on fluorescent staining. CD34+CD59+ and CD34+CD59− cells from PNH/AA patients showed similarly impaired primary and secondary clonogeneic efficiency. The progeny derived from CD34+CD59− cells were both CD59− and CD55−. A very small population of CD34+CD59− cells was also detected in some normal volunteers; after sorting, these CD34+CD59− cells formed normal numbers of colonies, but their progeny showed lower CD59 levels. Our results are consistent with the existence of PIG-A–deficient clones in some normal individuals. In PNH/AA, progenitor and stem cells are decreased in number and function, but the proliferation in vitro is affected similarly in GPI-protein–deficient clones and in phenotypically normal cells. As measured in the in vitro assays, expansion of PIG-A– clones appears not be caused by an intrinsic growth advantage of cells with the PNH phenotype.

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.

scholarly journals Oral Immunization with a Combination of Plasmodium yoelii Merozoite Surface Proteins 1 and 4/5 Enhances Protection against Lethal Malaria Challenge

2004 ◽  
Vol 72 (10) ◽  
pp. 6172-6175 ◽  
Author(s):  
Lina Wang ◽  
Matthew W. Goschnick ◽  
Ross L. Coppel
Keyword(s):  
Escherichia Coli ◽  
Malaria Infection ◽  
Surface Protein ◽  
Merozoite Surface Protein ◽  
Oral Immunization ◽  
Plasmodium Yoelii ◽  
Antibody Responses ◽  
Surface Proteins ◽  
Merozoite Surface Protein 1

ABSTRACT Oral immunization of mice with Escherichia coli-expressed Plasmodium yoelii merozoite surface protein 4/5 or the C-terminal 19-kDa fragment of merozoite surface protein 1 induced systemic antibody responses and protected mice against lethal malaria infection. A combination of these two proteins administered orally conferred improved protection compared to that conferred by either protein administered alone.

scholarly journals Comparative and Functional Analysis of Sortase-Dependent Proteins in the Predicted Secretome of Lactobacillus salivarius UCC118

2006 ◽  
Vol 72 (6) ◽  
pp. 4143-4153 ◽  
Author(s):  
Jan-Peter van Pijkeren ◽  
Carlos Canchaya ◽  
Kieran A. Ryan ◽  
Yin Li ◽  
Marcus J. Claesson ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Binding Protein ◽  
Surface Protein ◽  
Fold Increase ◽  
Transcript Level ◽  
Surface Proteins ◽  
Logarithmic Phase ◽  
Lactobacillus Salivarius ◽  
Binding Domains

ABSTRACT Surface proteins are important factors in the interaction of probiotic and pathogenic bacteria with their environment or host. We performed a comparative bioinformatic analysis of four publicly available Lactobacillus genomes and the genome of Lactobacillus salivarius subsp. salivarius strain UCC118 to identify secreted proteins and those linked to the cell wall. Proteins were identified which were predicted to be anchored by WXL-binding domains, N- or C-terminal anchors, GW repeats, lipoprotein anchors, or LysM-binding domains. We identified 10 sortase-dependent surface proteins in L. salivarius UCC118, including three which are homologous to mucus-binding proteins (LSL_0152, LSL_0311, and LSL_1335), a collagen-binding protein homologue (LSL_2020b), two hypothetical proteins (LSL_1838 and LSL_1902b), an enterococcal surface protein homologue (LSL_1085), a salivary agglutinin-binding homologue (LSL_1832b), an epithelial binding protein homologue (LSL_1319), and a proteinase homologue (LSL_1774b). However, two of the genes are gene fragments and four are pseudogenes, suggesting a lack of selection for their function. Two of the 10 genes were not transcribed in vitro, and 1 gene showed a 10-fold increase in transcript level in stationary phase compared to logarithmic phase. The sortase gene was deleted, and three genes encoding sortase-dependent proteins were disrupted. The sortase mutant and one sortase-dependent protein (mucus-binding homologue) mutant showed a significant reduction in adherence to human epithelial cell lines. The genome-wide investigation of surface proteins can thus help our understanding of their roles in host interaction.

scholarly journals A high-molecular-mass cell-surface protein from Lactobacillus reuteri 1063 adheres to mucus components The GenBank accession number for the sequence reported in this paper is AF120104.

Microbiology ◽  
2002 ◽  
Vol 148 (2) ◽  
pp. 433-442 ◽  
Author(s):  
Stefan Roos ◽  
Hans Jonsson
Keyword(s):  
Cell Surface ◽  
Lactobacillus Reuteri ◽  
Surface Protein ◽  
Surface Proteins ◽  
Cell Surface Protein ◽  
Intestinal Mucus ◽  
A Cell ◽  
Molecular Masses ◽  
Ph Range

A gene from Lactobacillus reuteri 1063 encoding a cell-surface protein, designated Mub, that adheres to mucus components in vitro has been cloned and sequenced. The deduced amino acid sequence of Mub (358 kDa) shows the presence of 14 approximately 200 aa repeats and features typical for other cell-surface proteins of Gram-positive bacteria. Fusion proteins consisting of different repeats of Mub and the maltose-binding protein (MBP) were produced. These proteins adhered to pig mucus components, with molecular masses ranging from <0·1 to >2 MDa, to pig gastric mucin and to hen intestinal mucus. The binding of Mub to mucus components occurred in the pH range 3–7·4, with maximum binding at pH 4–5 and could be partly inhibited by the glycoprotein fetuin. Affinity-purified antibodies against recombinant Mub were used in immunofluorescence microscopy to demonstrate the presence of Mub on the cell surface of strain 1063. By using the antibodies in a Western blot analysis, Mub could also be detected in the growth medium. The results implicate Mub as a cell-surface protein that is involved in Lactobacillus interactions with mucin and in colonization of the digestive tract.

scholarly journals Redox control of surface protein sulphhydryls in bovine spermatozoa reversibly modulates sperm adhesion to the oviductal epithelium and capacitation

Reproduction ◽  
2009 ◽  
Vol 138 (1) ◽  
pp. 33-43 ◽  
Author(s):  
Roberto Gualtieri ◽  
Valentina Mollo ◽  
Gennaro Duma ◽  
Riccardo Talevi
Keyword(s):  
Surface Protein ◽  
Surface Proteins ◽  
Sperm Surface ◽  
Sperm Suspension ◽  
Oviductal Epithelium ◽  
Bovine Spermatozoa ◽  
Sulphated Glycosaminoglycans ◽  
Oviductal Fluid ◽  
Adhesion Assays

Oviductal fluid molecules, such as sulphated glycosaminoglycans and disulphide-reductants, may represent periovulatory signals for the release of spermatozoa from the oviductal reservoir in the bovine species. Disulphide-reductants release spermatozoa through the reduction of sperm-surface disulphides to sulphhydryls (SH). Herein, we studied sperm-surface protein SH through labelling with maleimidylpropionyl biocytin in the initial sperm suspension, in the subpopulations able and unable to adhere to the in vitro cultured oviductal epithelium, and in spermatozoa released either through the disulphide-reductant penicillamine (PEN) or the sulphated glycosaminoglycan heparin (HEP). Adhesion assays were performed to study the ability of released spermatozoa to readhere to the oviductal epithelium. Results showed that the level of SH in sperm-surface proteins was: 1) low in adhering spermatozoa; 2) high in spermatozoa unable to adhere; and 3) markedly increased in released spermatozoa. Adhesion assays showed that: 1) PEN-released spermatozoa promptly recovered adhesion after removal of the disulphide-reductant and could be released again in response to PEN; 2) conversely, a limited number of HEP-released spermatozoa was able to readhere to the oviductal epithelium and this ability was not affected by HEP removal. Recovery of adhesion was associated to reoxidation of sperm-surface protein SH and to the reversal of capacitation. In conclusion, redox modulation of sperm-surface protein SH is involved in the release of spermatozoa adhering to the oviduct in vitro; the reversible action of disulphide-reductants might be responsible for intermittent phases of adhesions and releases; and the irreversible action of HEP indicates that it may represent a terminal releasing signal.

scholarly journals Neutralizing Human Antibodies against Severe Acute Respiratory Syndrome Coronavirus 2 Isolated from a Human Synthetic Fab Phage Display Library

2021 ◽  
Vol 22 (4) ◽  
pp. 1913
Author(s):  
Yu Jung Kim ◽  
Min Ho Lee ◽  
Se-Ra Lee ◽  
Hyo-Young Chung ◽  
Kwangmin Kim ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Phage Display ◽  
Viral Entry ◽  
Phage Display Library ◽  
Cross Reactivity ◽  
Spike Protein ◽  
Receptor Protein ◽  
In Vitro Assays ◽  
Global Threat

Since it was first reported in Wuhan, China, in 2019, the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused a pandemic outbreak resulting in a tremendous global threat due to its unprecedented rapid spread and an absence of a prophylactic vaccine or therapeutic drugs treating the virus. The receptor-binding domain (RBD) of the SARS-CoV-2 spike protein is a key player in the viral entry into cells through its interaction with the angiotensin-converting enzyme 2 (ACE2) receptor protein, and the RBD has therefore been crucial as a drug target. In this study, we used phage display to develop human monoclonal antibodies (mAbs) that neutralize SARS-CoV-2. A human synthetic Fab phage display library was panned against the RBD of the SARS-CoV-2 spike protein (SARS-2 RBD), yielding ten unique Fabs with moderate apparent affinities (EC50 = 19–663 nM) for the SARS-2 RBD. All of the Fabs showed no cross-reactivity to the MERS-CoV spike protein, while three Fabs cross-reacted with the SARS-CoV spike protein. Five Fabs showed neutralizing activities in in vitro assays based on the Fabs’ activities antagonizing the interaction between the SARS-2 RBD and ACE2. Reformatting the five Fabs into immunoglobulin Gs (IgGs) greatly increased their apparent affinities (KD = 0.08–1.0 nM), presumably due to the effects of avidity, without compromising their non-aggregating properties and thermal stability. Furthermore, two of the mAbs (D12 and C2) significantly showed neutralizing activities on pseudo-typed and authentic SARS-CoV-2. Given their desirable properties and neutralizing activities, we anticipate that these human anti-SARS-CoV-2 mAbs would be suitable reagents to be further developed as antibody therapeutics to treat COVID-19, as well as for diagnostics and research tools.

scholarly journals Evidence that Surface Proteins Sn14 and Sn16 of Sarcocystis neurona Merozoites Are Involved in Infection and Immunity

1998 ◽  
Vol 66 (5) ◽  
pp. 1834-1838 ◽  
Author(s):  
Fang Ting Liang ◽  
David E. Granstrom ◽  
Xiao Min Zhao ◽  
John F. Timoney
Keyword(s):  
Surface Protein ◽  
Neutralization Assay ◽  
Etiologic Agent ◽  
Surface Proteins ◽  
Host Cells ◽  
Inhibitory Effects ◽  
Sarcocystis Neurona ◽  
Equine Protozoal Myeloencephalitis ◽  
Useful Components

ABSTRACT Sarcocystis neurona is the etiologic agent of equine protozoal myeloencephalitis (EPM). Based on an analysis of 25,000 equine serum and cerebrospinal fluid (CSF) samples, including samples from horses with neurologic signs typical of EPM or with histologically or parasitologically confirmed EPM, four major immunoblot band patterns have been identified. Twenty-three serum and CSF samples representing each of the four immunoblot patterns were selected from 220 samples from horses with neurologic signs resembling EPM and examined for inhibitory effects on the infectivity of S. neurona by an in vitro neutralization assay. A high correlation between immunoblot band pattern and neutralizing activity was detected. Two proteins, Sn14 and Sn16 (14 and 16 kDa, respectively), appeared to be important for in vitro infection. A combination of the results of surface protein labeling, immunoprecipitation, Western blotting, and trypsin digestion suggests that these molecules are surface proteins and may be useful components of a vaccine against S. neuronainfection. Although S. neurona is an obligate intracellular parasite, it is potentially a target for specific antibodies which may lyse merozoites via complement or inhibit their attachment and penetration to host cells.

scholarly journals Temporal Changes in Outer Surface Proteins A and C of the Lyme Disease-Associated Spirochete, Borrelia burgdorferi, during the Chain of Infection in Ticks and Mice

2000 ◽  
Vol 38 (1) ◽  
pp. 382-388 ◽  
Author(s):  
Tom G. Schwan ◽  
Joseph Piesman
Keyword(s):  
Lyme Disease ◽  
Borrelia Burgdorferi ◽  
Outer Surface ◽  
Ixodes Scapularis ◽  
Protein A ◽  
Surface Protein ◽  
Surface Proteins ◽  
In Vitro Cultivation ◽  
Outer Surface Protein A

ABSTRACT The Lyme disease-associated spirochete, Borrelia burgdorferi, is maintained in enzootic cycles involvingIxodes ticks and small mammals. Previous studies demonstrated that B. burgdorferi expresses outer surface protein A (OspA) but not OspC when residing in the midgut of unfed ticks. However, after ticks feed on blood, some spirochetes stop making OspA and express OspC. Our current work examined the timing and frequency of OspA and OspC expression by B. burgdorferi in infected Ixodes scapularis nymphs as they fed on uninfected mice and in uninfected I. scapularis larvae and nymphs as they first acquired spirochetes from infected mice. Smears of midguts from previously infected ticks were prepared at 12- or 24-h intervals following attachment through repletion at 96 h, and spirochetes were stained for immunofluorescence for detection of antibodies to OspA and OspC. As shown previously, prior to feeding spirochetes in nymphs expressed OspA but not OspC. During nymphal feeding, however, the proportion of spirochetes expressing OspA decreased, while spirochetes expressing OspC became detectable. In fact, spirochetes rapidly began to express OspC, with the greatest proportion of spirochetes having this protein at 48 h of attachment and then with the proportion decreasing significantly by the time that the ticks had completed feeding. In vitro cultivation of the spirochete at different temperatures showed OspC to be most abundant when the spirochetes were grown at 37°C. Yet, the synthesis of this protein waned with continuous passage at this temperature. Immunofluorescence staining of spirochetes in smears of midguts from larvae and nymphs still attached or having completed feeding on infected mice demonstrated that OspA but not OspC was produced by these spirochetes recently acquired from mice. Therefore, the temporal synthesis of OspC by spirochetes only in feeding ticks that were infected prior to the blood meal suggests that this surface protein is involved in transmission from tick to mammal but not from mammal to tick.

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