cell agglutination
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Author(s):  
Bhavya Sahithi Velagapudi ◽  
Hemanth Sai Nannapaneni ◽  
Akanksha Alampally ◽  
Suryanarayana Veeravilli ◽  
Duggipogu Praveen Kumar ◽  
...  

Lectin has various physiological roles in cell agglutination, based on their carbohydrate-binding properties, plant lectins are widely used for the detection, segregation, and characterization of glycoconjugates. Rhesus (Rh) factor is a protein that is inherited and found on the surface of red blood cells. If the surface protein is present, the RBC is Rh positive; otherwise, it is Rh-negative in nature. In this paper, we use agglutination reactions to investigate the effect of different cold and hot water extracted plants on RBC antigens as an alternative to commercial monoclonal antibodies. Extensive research on the sequence homology and 3-D structure of various plant lectins suggests that they have been conserved throughout evolution and may play important physiological roles that are still unknown.


Author(s):  
Kshitij Srivastava ◽  
Kamille A. West ◽  
Valeria De Giorgi ◽  
Michael R. Holbrook ◽  
Nicolai V. Bovin ◽  
...  

We recently developed a red cell based assay to detect SARS-CoV-2 antibodies in human plasma. In the current study, we show the hands-on application of this assay in a group of COVID-19 convalescent plasma donors and healthy individuals.


2021 ◽  
Author(s):  
Damilola R Oresegun ◽  
Peter Thorpe ◽  
Ernest Diez Benavente ◽  
Susana Campino ◽  
Muh Fauzi ◽  
...  

Plasmodium knowlesi, a malaria parasite of old-world macaque monkeys, is used extensively to model Plasmodium biology. Recently P. knowlesi was found in the human population of Southeast Asia, particularly Malaysia. P. knowlesi causes un-complicated to severe and fatal malaria in the human host with features in common with the more prevalent and virulent malaria caused by Plasmodium falciparum. As such P. knowlesi presents a unique opportunity to inform an experimental model for malaria with clinical data from same-species human infections. Experimental lines of P. knowlesi represent well characterised genetically static parasites and to maximise their utility as a backdrop for understanding malaria pathophysiology, genetically diverse contemporary clinical isolates, essentially wild-type, require comparable characterization. The Oxford Nanopore PCR-free long-read sequencing platform was used to sequence P. knowlesi parasites from archived clinical samples. The sequencing platform and assembly pipeline was designed to facilitate capturing data on important multiple gene families, including the P. knowlesi schizont-infected cell agglutination (SICA) var genes and the Knowlesi-Interspersed Repeats (KIR) genes. The SICAvar and KIR gene families code for antigenically variant proteins that have been difficult to resolve and characterise. Analyses presented here suggest that the family members have arisen through a process of gene duplication, selection pressure and variation. Highly evolving genes tend to be located proximal to genetic elements that drive change rather than regions that support core gene conservation. For example, the virulence-associated P. falciparum erythrocyte membrane protein (PfEMP1) gene family members are restricted to relatively unstable sub-telomeric regions. In contrast the SICAvar nd KIR genes are located throughout the genome but as the study presented here shows, they occupy otherwise gene-sparse chromosomal locations. The novel methods presented here offer the malaria research community new tools to generate comprehensive genome sequence data from small clinical samples and renewed insight into these complex real-world parasites.


Blood ◽  
2021 ◽  
Vol 138 (Supplement 1) ◽  
pp. 1878-1878
Author(s):  
Willy A. Flegel ◽  
Kshitij Srivastava ◽  
Valeria De Giorgi ◽  
Michael R Holbrook ◽  
Nicolai V Bovin ◽  
...  

Abstract Background. Serologic assays detecting antibodies against the SARS-CoV-2 spike or nucleocapsid proteins have been developed to advance our understanding of the prognosis and clinical course of the COVID-19 disease. We recently developed a red cell agglutination-based assay to detect severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) antibodies. This assay uses peptide fragments of the SARS-CoV-2 spike protein to label red cells (C19-kodecytes). We performed a clinical evaluation of this C19-kodecyte assay in COVID-19 convalescent plasma (CCP) donors previously assessed with 2 commercial immunoassays and a virus neutralizing assay. Methods. Red cells were coated with peptide fragments of the SARS-CoV-2 spike protein. We tested plasma samples from 140 CCP donors. The results were compared with those of a virus neutralizing assay and 2 commercial chemiluminescent antibody tests: anti-SARS-CoV-2 Total (IgG, IgM and IgA) assay and anti-SARS-CoV-2 IgG assay (Ortho). Inter-rater agreement between the different assays was measured using Cohen's kappa. Specificity was tested with 150 plasma samples, collected in 2008, more than a decade before the COVID-19 outbreak and with 125 plasma samples, collected in 2020 from consecutive healthy volunteer donors, who tested negative for the Ortho Total assay. Testing was performed using the column agglutination technique commonly employed for blood typing. Results. The area under the ROC curve (AUC) for the C19-kodecyte assay reached 0.95 (95% CI: 0.93 - 0.97) with sensitivity of 92.8% (95% CI: 86.9% - 96.3%) and specificity of 96.3% (95% CI: 93.2% - 98.1%). In almost all of the 40 CCP donors with longitudinal data, the antibody concentration decreased during the follow-up, which ranged from 7 to 44 weeks. In the 140 CCP donors, we compared the C19-kodecyte score to the antibody concentrations from the 2 FDA authorized assays (Ortho Total and Ortho IgG) and the titer in the neutralizing assay. There was a positive relationship between the results of all 4 assays. The Spearman's correlation of our assay was 0.20 with the neutralizing assay (0.49 with IgG, and 0.41 with Total assays). Conclusions. Sensitivity and specificity of the C19-kodecyte assay were within the minimum performance range required by the FDA for EUA authorization of serology tests. The limited correlation in assay reaction strengths suggested that the assays may be influenced by different antibody specificities. Unlike the other 84 FDA authorized serologic tests for SARS-CoV-2, this C19-kodecyte assay is a simple and rapid test that can be easily established in any blood typing laboratory worldwide using its routine setup for column agglutination or tube technique. The technique could vastly improve assay capacity, particularly in resource limited hospital blood banks. Disclosures Bovin: Kode Biotech: Current Employment, Current holder of stock options in a privately-held company. Henry: Kode Biotech: Current Employment, Current holder of stock options in a privately-held company.


Foods ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 1770
Author(s):  
Francesca Colombo ◽  
Chiara Di Lorenzo ◽  
Katia Petroni ◽  
Marco Silano ◽  
Roberto Pilu ◽  
...  

Oxidative stress, one among the several factors responsible for the gluten toxicity in celiac disease, together with inflammation and duodenal mucosal injury, are only partially reduced by the gluten-free diet. Thanks to their phenolic profile, the pigmented varieties of corn could be an interesting source of dietary antioxidants for the formulation of new gluten-free ingredients. The aim of this research was: (1) to characterize the phenolic profile and the associated antioxidant properties of corn samples with different pigmentation, using spectrophotometric and chromatographic techniques and (2) to assess the stability of anthocyanins during the gastro-intestinal digestion. The pigmented varieties showed a significantly higher content of polyphenols compared to the common yellow varieties and, as a consequence, a higher antioxidant activity. Although corn is among the cereals most frequently used in gluten-free products, it can produce an inflammatory response in some celiac patients. Therefore, after the chemical characterization, the safety of the pigmented varieties for celiac patients was confirmed using different in vitro models (cell agglutination test and the measure of transepithelial electrical resistance). Although in vivo studies are necessary, the data collected in this study underline that the pigmented corn could have a role in reducing the oxidative stress at the intestinal level in celiac subjects.


2021 ◽  
Vol 14 (02) ◽  
pp. 1007-1018
Author(s):  
Rupachandra S ◽  
Mario Prateek Selvam ◽  
Nisha Muthukumaran ◽  
Sangamithra Senthilkumar ◽  
Sandhiya Vaidhyalingam ◽  
...  

Plant peptides have gained attention in the medicinal field due to their high anti-microbial and anti-cancer properties. Various plant sources are being used to extract proteins and peptides to be used as a cure for a variety of diseases. The latest studies show that plant peptides are effective in the treatment of cancer due to their ability to preferentially bind to the receptors or membranes of cancer cells leading to tumour growth inhibition, cytotoxicity, decreased proliferation, and apoptosis. The peptides get internalized into the cells causing cancer cell agglutination and aggregation. In addition to acting as therapeutic agents, plant peptides are also used for the targeting of drugs specific to cancer cells. In this study, bioactive peptides were isolated from the seeds of Momordica dioica and leaves of Solanum trilobatum. They were screened and identified using HPLC and MALDI-TOF techniques. In this study, apoptosis was analyzed by the Hoechst 33342 staining method which detected the presence of condensed pycnotic nuclei in apoptotic COLO320DM and COLO205 colon cancer cellsat the maximum concentrations of 150 and 175 µg/mL of plant peptides.Further DCFH-DA staining indicated the intracellular ROS production in the treated COLO320DM and COLO205 colon cancer cells. Thus, the isolated bioactive plant peptides can be formulated towards the development of effective anticancer drugs for the treatment of colon cancer in humans.


2021 ◽  
Author(s):  
Kshitij Srivastava ◽  
Kamille A West ◽  
Valeria De Giorgi ◽  
Michael R Holbrook ◽  
Nicolai V Bovin ◽  
...  

Red cells can be labelled with peptides from the SARS-CoV-2 spike protein and used for serologic screening of SARS-CoV-2 antibodies. We evaluated 140 convalescent COVID-19 patients and 275 healthy controls using this C19-kodecyte assay. The analytical performance of the new assay was compared with a virus neutralizing assay and 2 commercial chemiluminescent antibody tests (Total assay and IgG assay, Ortho). The C19-kodecyte assay detected SARS-CoV-2 antibodies with a sensitivity of 92.8% and specificity of 96.3%, well within the minimum performance range required by FDA for EUA authorization of serologic tests. The Cohen's kappa coefficient was 0.90 indicating an almost perfect agreement with the Total assay. The Pearson correlation coefficient was 0.20 with the neutralizing assay (0.49 with IgG, and 0.41 with Total assays). The limited correlation in assay reaction strengths suggested that the assays may detect different antibody specificities. Our easily scalable C19-kodecyte assay may vastly improve test capacity in blood typing laboratories using their routine setups for column agglutination technique.


2021 ◽  
Author(s):  
Chee Yik Chang ◽  
Huang Hin Chin ◽  
Pek Woon Chin ◽  
Masliza Zaid

Abstract Cold agglutinin-mediated autoimmune hemolytic anemia (AIHA) is a rare disorder associated with COVID-19 infection. Here, we present a case of COVID-19 pneumonia with concomitant cold agglutinin syndrome (CAS). On admission, the patient was anemic with reticulocytosis and the direct antiglobulin test showed the presence of anti-complement (C3d) antibodies. Peripheral blood film demonstrated red cell agglutination which was dispersible on blood warming. Chest radiography showed bilateral lower zone ground glass appearance. SARS-CoV-2 was detected in the nasopharyngeal and oropharyngeal swab samples by the RT-PCR method. Additional workup for malignancy, autoimmune disease, and other infections yielded negative results. Systemic corticosteroids and oxygen therapy were administered as she developed hypoxic respiratory failure. In addition, she received packed cell transfusion in view of hemolysis. Following corticosteroid and other supportive therapy, she recovered and was discharged well.


2021 ◽  
Author(s):  
Alain Townsend ◽  
Pramila Rijal ◽  
Tiong Kit Tan ◽  
Etienne Joly

Abstract Serological detection of antibodies to SARS-CoV-2 is essential for establishing rates ofseroconversion in populations, and for seeking evidence for a level of antibody that may beprotective against COVID-19 disease. Several high-performance commercial tests have beendescribed, but these require centralised laboratory facilities that are comparativelyexpensive, and therefore not available universally. Red cell agglutination tests do notrequire special equipment, are read by eye, have short development times, low cost and canbe applied at the Point of Care. We describe a quantitative Haemagglutination test (HAT) forthe detection of antibodies to the receptor binding domain of the SARS-CoV-2 spike protein.The HAT has a sensitivity of 90% and specificity of 99% for detection of antibodies after aPCR diagnosed infection. We will supply aliquots of the test reagent sufficient for tenthousand test wells free of charge to qualified research groups anywhere in the world.


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