scholarly journals Improved Plasmodium falciparum dilution cloning through efficient quantification of parasite numbers and c-SNARF detection

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Tatiane Macedo-Silva ◽  
Sanjay A. Desai ◽  
Gerhard Wunderlich
Keyword(s):  
Flow Cytometry ◽  
Plasmodium Falciparum ◽  
Ex Vivo ◽  
Traditional Approach ◽  
Parasite Growth ◽  
Ph Indicator ◽  
Cell Counts ◽  
Clonal Lines ◽  
Limiting Dilution ◽  
Limiting Dilution Cloning

Abstract Background Molecular and genetic studies of blood-stage Plasmodium falciparum parasites require limiting dilution cloning and prolonged cultivation in microplates. The entire process is laborious and subject to errors due to inaccurate dilutions at the onset and failed detection of parasite growth in individual microplate wells. Methods To precisely control the number of parasites dispensed into each microplate well, parasitaemia and total cell counts were determined by flow cytometry using parasite cultures stained with ethidium bromide or SYBR Green I. Microplates were seeded with 0.2 or 0.3 infected cells/well and cultivated with fresh erythrocytes. The c-SNARF fluorescent pH indicator was then used to reliably detect parasite growth. Results Flow cytometry required less time than the traditional approach of estimating parasitaemia and cell numbers by microscopic examination. The resulting dilutions matched predictions from Poisson distribution calculations and yielded clonal lines. Addition of c-SNARF to media permitted rapid detection of parasite growth in microplate wells with high confidence. Conclusion The combined use of flow cytometry for precise dilution and the c-SNARF method for detection of growth improves limiting dilution cloning of P. falciparum. This simple approach saves time, is scalable, and maximizes identification of desired parasite clones. It will facilitate DNA transfection studies and isolation of parasite clones from ex vivo blood samples.

scholarly journals Enhanced virulence of Plasmodium falciparum in blood of diabetic patients

PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0249666
Author(s):  
Jun-Hong Ch’ng ◽  
Kirsten Moll ◽  
Katja Wyss ◽  
Ulf Hammar ◽  
Mikael Rydén ◽  
...  
Keyword(s):  
Type 2 Diabetes ◽  
Plasmodium Falciparum ◽  
Blood Glucose ◽  
Severe Malaria ◽  
Ex Vivo ◽  
Parasite Growth ◽  
Sub Saharan Africa ◽  
Diabetic Patients ◽  
Good Glycemic Control

Rising prevalence of diabetes in sub-Saharan Africa, coupled with continued malaria transmission, has resulted more patients dealing with both communicable and non-communicable diseases. We previously reported that travelers with type 2 diabetes mellitus (T2DM) infected with Plasmodium falciparum were three times more likely to develop severe malaria than non-diabetics. Here we explore the biological basis for this by testing blood from uninfected subjects with type 1 and type 2 diabetes, ex vivo, for their effects on parasite growth and rosetting (binding of infected erythrocytes to uninfected erythrocytes). Rosetting was associated with type 2 diabetes, blood glucose and erythrocyte sedimentation rate (ESR), while parasite growth was positively associated with blood glucose, glycated hemoglobin (HbA1c), body mass index (BMI), fibrinogen and triglycerides. This study establishes a link between diabetes and malaria virulence assays, potentially explaining the protective effect of good glycemic control against severe malaria in subjects with diabetes.

Synthesis of a Novel Curcumin Derivative as a Potential Imaging Probe in Alzheimer’s Disease Imaging

2019 ◽  
Vol 16 (8) ◽  
pp. 723-731 ◽  
Author(s):  
Alexander Sturzu ◽  
Sumbla Sheikh ◽  
Hubert Kalbacher ◽  
Thomas Nägele ◽  
Christopher Weidenmaier ◽  
...  
Keyword(s):  
Alzheimer’S Disease ◽  
Alzheimer's Disease ◽  
Flow Cytometry ◽  
Transgenic Mice ◽  
Ex Vivo ◽  
Amyloid Plaques ◽  
Laser Scanning Microscopy ◽  
Β Amyloid ◽  
Curcumin Derivative

Background: Curcumin has been of interest in the field of Alzheimer’s disease. Early studies on transgenic mice showed promising results in the reduction of amyloid plaques.However, curcumin is very poorly soluble in aqueous solutions and not easily accessible to coupling as it contains only phenolic groups as potential coupling sites. For these reasons only few imaging studies using curcumin bound as an ester were performed and curcumin is mainly used as nutritional supplement. Methods: In the present study we produced an aminoethyl ether derivative of curcumin using a nucleophilic substitution reaction. This is a small modification and should not impact the properties of curcumin while introducing an easily accessible reactive amino group. This novel compound could be used to couple curcumin to other molecules using the standard methods of peptide synthesis. We studied the aminoethyl-curcumin compound and a tripeptide carrying this aminoethyl-curcumin and the fluorescent dye fluorescein (FITC-curcumin) in vitro on cell culture using confocal laser scanning microscopy and flow cytometry. Then these two substances were tested ex vivo on brain sections prepared from transgenic mice depicting Alzheimer-like β-amyloid plaques. Results: In the in vitro CLSM microscopy and flow cytometry experiments we found dot-like unspecific uptake and only slight cytotoxicity correlating with this uptake. As these measurements were optimized for the use of fluorescein as dye we found that the curcumin at 488nm fluorescence excitation was not strong enough to use it as a fluorescence marker in these applications. In the ex vivo sections CLSM experiments both the aminoethyl-curcumin and the FITC-curcumin peptide bound specifically to β- amyloid plaques. Conclusion: In conclusion we successfully produced a novel curcumin derivative which could easily be coupled to other imaging or therapeutic molecules as a sensor for amyloid plaques.

scholarly journals Comparison of leucocyte profiles between healthy children and those with asymptomatic and symptomatic Plasmodium falciparum infections

2020 ◽  
Vol 19 (1) ◽  
Author(s):  
Diana Ahu Prah ◽  
Linda Eva Amoah ◽  
Matthew P. Gibbins ◽  
Yaw Bediako ◽  
Aubrey J. Cunnington ◽  
...  
Keyword(s):  
T Cells ◽  
Plasmodium Falciparum ◽  
Peripheral Blood ◽  
Parasite Load ◽  
Study Groups ◽  
Healthy Children ◽  
Peripheral Cell ◽  
Peripheral Blood Leucocyte ◽  
Cell Counts ◽  
Significant Difference

Abstract Background The immune mechanisms that determine whether a Plasmodium falciparum infection would be symptomatic or asymptomatic are not fully understood. Several studies have been carried out to characterize the associations between disease outcomes and leucocyte numbers. However, the majority of these studies have been conducted in adults with acute uncomplicated malaria, despite children being the most vulnerable group. Methods Peripheral blood leucocyte subpopulations were characterized in children with acute uncomplicated (symptomatic; n = 25) or asymptomatic (n = 67) P. falciparum malaria, as well as malaria-free (uninfected) children (n = 16) from Obom, a sub-district of Accra, Ghana. Leucocyte subpopulations were enumerated by flow cytometry and correlated with two measures of parasite load: (a) plasma levels of P. falciparum histidine-rich protein 2 (PfHRP2) as a proxy for parasite biomass and (b) peripheral blood parasite densities determined by microscopy. Results In children with symptomatic P. falciparum infections, the proportions and absolute cell counts of total (CD3 +) T cells, CD4 + T cells, CD8 + T cells, CD19 + B cells and CD11c + dendritic cells (DCs) were significantly lower as compared to asymptomatic P. falciparum-infected and uninfected children. Notably, CD15 + neutrophil proportions and cell counts were significantly increased in symptomatic children. There was no significant difference in the proportions and absolute counts of CD14 + monocytes amongst the three study groups. As expected, measures of parasite load were significantly higher in symptomatic cases. Remarkably, PfHRP2 levels and parasite densities negatively correlated with both the proportions and absolute numbers of peripheral leucocyte subsets: CD3 + T, CD4 + T, CD8 + T, CD19 + B, CD56 + NK, γδ + T and CD11c + cells. In contrast, both PfHRP2 levels and parasite densities positively correlated with the proportions and absolute numbers of CD15 + cells. Conclusions Symptomatic P. falciparum infection is correlated with an increase in the levels of peripheral blood neutrophils, indicating a role for this cell type in disease pathogenesis. Parasite load is a key determinant of peripheral cell numbers during malaria infections.

scholarly journals Publisher Correction to: Direct contact between Plasmodium falciparum and human B-cells in a novel co-culture increases parasite growth and affects B-cell growth

2021 ◽  
Vol 20 (1) ◽  
Author(s):  
Sreenivasulu B. Reddy ◽  
Noemi Nagy ◽  
Caroline Rönnberg ◽  
Francesca Chiodi ◽  
Allan Lugaajju ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
B Cells ◽  
Cell Growth ◽  
B Cell ◽  
Direct Contact ◽  
Parasite Growth ◽  
Human B Cells

scholarly journals Interaction of Plasmodium falciparum apicortin with α- and β-tubulin is critical for parasite growth and survival

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Malabika Chakrabarti ◽  
Nishant Joshi ◽  
Geeta Kumari ◽  
Preeti Singh ◽  
Rumaisha Shoaib ◽  
...  
Keyword(s):  
Plasmodium Falciparum ◽  
Life Cycle ◽  
Specific Protein ◽  
Parasite Growth ◽  
Growth And Survival ◽  
Apicomplexan Parasites ◽  
Parasite Replication ◽  
Main Components ◽  
Β Tubulin

AbstractCytoskeletal structures of Apicomplexan parasites are important for parasite replication, motility, invasion to the host cell and survival. Apicortin, an Apicomplexan specific protein appears to be a crucial factor in maintaining stability of the parasite cytoskeletal assemblies. However, the function of apicortin, in terms of interaction with microtubules still remains elusive. Herein, we have attempted to elucidate the function of Plasmodium falciparum apicortin by monitoring its interaction with two main components of parasite microtubular structure, α-tubulin-I and β-tubulin through in silico and in vitro studies. Further, a p25 domain binding generic drug Tamoxifen (TMX), was used to disrupt PfApicortin-tubulin interactions which led to the inhibition in growth and progression of blood stage life cycle of P. falciparum.

scholarly journals 588 Targeting GITR enhances human tumour-infiltrating T cell functionality in mismatch repair proficient primary colorectal carcinoma and liver metastases

2020 ◽  
Vol 8 (Suppl 3) ◽  
pp. A623-A623
Author(s):  
Yannick Rakké ◽  
Lucia Campos Carrascosa ◽  
Adriaan van Beek ◽  
Valeska de Ruiter ◽  
Michael Doukas ◽  
...  
Keyword(s):  
Flow Cytometry ◽  
T Cells ◽  
T Cell ◽  
Colorectal Carcinoma ◽  
Liver Metastases ◽  
Mismatch Repair ◽  
Immune Checkpoint ◽  
Ex Vivo ◽  
Human Tumour ◽  
Functional Assays

BackgroundImmune checkpoint blockade (ICB; e.g. anti-PD-1/-CTLA-4) has been proven to be clinically effective in mismatch repair deficient (dMMR) colorectal carcinoma (CRC). Yet, the majority of patients carry mismatch repair proficient (pMMR) CRC, especially those with liver metastasis, and do not respond to ICB. Here, we studied the effect of immune checkpoint stimulation via GITR targeting on human tumour-infiltrating lymphocyte (TIL) functionality in pMMR primary CRC and liver metastases (CRLM).MethodsHuman TIL were isolated from freshly resected pMMR tumours of patients with primary CRC (stage 1–3) or liver metastases (table 1). GITR expression on TIL was determined using flow cytometry and compared to leukocytes isolated from blood (PBMC) and tumour-free surrounding tissues (tumour-free colon/liver, resp. TFC and TFL). Ex vivo functional assays were used to assess TIL expansion, activation and cytokine/cytotoxic mediator secretion upon CD3/CD28 bead activation and co-stimulation using an antibody-crosslinked recombinant trimeric GITR ligand (GITRL).ResultsGITR was overexpressed on TIL when compared to other stimulatory immune checkpoints (4-1BB, OX40). GITR expression was enhanced on CD4+ and CD8+ TIL compared to PBMC and TFC or TFL compartments in both primary CRC and CRLM. Among CD4+ TIL, GITR was increasingly expressed on CD45RA± FoxP3- helper T (Th), CD45RA- FoxP3int activated helper T (aTh), and CD45RA- FoxP3hi activated regulatory T cells (aTreg), respectively. Within CD8+ TIL, GITR expression was higher on TOX+ PD1Hi and putatively tumour-reactive CD103+ CD39+ TIL.1 Impaired effector cytokine production upon ex vivo PMA/ionomycin stimulation was observed in CD4+ and CD8+ GITR-expressing TIL, hinting to functional exhaustion of the target population. However, recombinant GITRL reinvigorated ex vivo TIL responses by significantly enhancing CD4+ and CD8+ TIL numbers and proinflammatory cytokine secretion in a dose-dependent manner (figure 1). Treg depletion did not fully abrogate the stimulatory effect of GITR ligation on CD4+ and CD8+ T cell expansion, demonstrating that the stimulatory effect was partly exerted via direct targeting GITR on effector T cells. Importantly, GITR-ligation also enhanced expansion of purified CD8+CD39+ TIL. Dual treatment with GITR ligand and nivolumab (anti-PD-1) further enhanced CD8+ TIL responses compared to GITR ligand monotherapy, whereas nivolumab alone did not show any effect.Abstract 588 Table 1Patient characteristicsPatient characteristics of patients included for FACS analysis and/or functional assays. † Pathologic staging was performed according to the AJCC 8th edition criteriaAbstract 588 Figure 1GITR ligation enhances CD4+ and CD8+ TIL expansionTIL were isolated from CRC or CRLM and cultured upon CD3/CD28 activation with or without GITRL (0.1–1.0 ug/mL) for 8 days. TIL numbers were acquired by flow cytometry and normalized to counting beads. Indicated is fold change relative to ctrl-treated TIL (n=10).ConclusionsAgonistic targeting of GITR enhances ex vivo human TIL functionality in pMMR CRC and might therefore be a promising approach for novel mono- or combinatorial immunotherapies in primary CRC and CRLM.AcknowledgementsN/ATrial RegistrationN/AEthics ApprovalThe study was approved by the medical ethics committee of the Erasmus Medical Center (MEC-2012-331).ConsentN/AReferenceDuhen T, Duhen R, Montler R, et al. Co-expression of CD39 and CD103 identifies tumor-reactive CD8 T cells in human solid tumors. Nat Commun 2018;9(1):2724. doi: 10.1038/s41467-018-05072-0.

scholarly journals FRI0015 PHENOTYPE AND FUNCTION OF THE PERIPHERAL BLOOD DENDRITIC CELLS OF PSORIASIS PATIENTS WITH AND WITHOUT ARTHRITIS

2020 ◽  
Vol 79 (Suppl 1) ◽  
pp. 578.1-579
Author(s):  
S. Schnitte ◽  
A. Fuchs ◽  
T. Funk ◽  
A. C. Pecher ◽  
D. Dörfel ◽  
...  
Keyword(s):  
Risk Factors ◽  
Flow Cytometry ◽  
Dendritic Cells ◽  
Psoriatic Arthritis ◽  
T Lymphocytes ◽  
Peripheral Blood ◽  
Surface Proteins ◽  
Research Support ◽  
Cross Sectional ◽  
Cell Counts

Background:Psoriasis is a frequent skin disease that can appear with an arthritic manifestation in approximately 30% of the cases [1]. The underlying excessive immune reaction caused by pro-inflammatory cytokines can be triggered by several risk factors [2]. Various subgroups of Dendritic cells (DCs) in the skin play a crucial role in the induction of the dermal inflammatory response [3].Objectives:As the role of peripheral blood DCs remains unknown and the cause of an arthritic manifestation is still not completely understood [4], this project aimed to detect differences in phenotype or function of peripheral blood DCs in psoriatic patients with or without arthritis.Methods:We analyzed peripheral blood cells of 60 psoriasis patients with and without arthritis. Different DC subpopulations were detected by flow cytometry. Monocyte-derived DCs were cultured with or without Lipopolysaccharides to gain immature (iDC) and mature (mDC) cells. The DC phenotype was determined by staining with CD80, CD83, CD86, CD206, CCR7, CD1a, HLA-DR, CD40, GPN-MB, DC209 and CD14. Their T-cell stimulatory capability was analyzed by co-incubation with Carboxyfluorescein succinimidyl ester stained lymphocytes and the quantification of CD4+ T-lymphocytes afterwards. To measure the migration capacity DCs were seated into transwell chambers with a semipermeable membrane and partly supplemented with Macrophage Inflammatory Protein 3 Beta (Mip3b). Migrated cells were detected by flow cytometry. Measured cell counts were normalized to cell counts without Mip3b stimulation.Results:Comparing the factor of increase of migrated mDC counts due to mip3b stimulation, we detected a significant lower rate in samples of patients with arthritis (PsA) compared to those of patients without (Ps). Assays of mDCs without mip3b stimulation showed a significant higher count of migrated cells in the samples of the arthritic group [Figure 1]. Cell counts with Mip3b stimulation did vary slightly in the groups. The DC subpopulations and the expression of analyzed cell surface proteins did not show significant differences. The amounts of stimulated T-Lymphocytes did not differ significantly.Figure 1.Migration essay showing mDCs following Mip3b (+miß3b) as multiples of mDCs without stimulation (-mip3b). The factor of increase is significantly lower in patients with arthritis (PsA) compared to patients without (Ps). Absolute counts of migrated mDCs without Mip3b are significantly higher in the arthritic group. Cell counts with stimulation do not differ significantly (data not shown). N=24, p<0.05Conclusion:CCL19 (Mip3b) is a potent ligand to the CCR7 receptor inducing migration of DCs towards the lymphatic node [5]. The CCR7 amounts on the DC surface did not differ significantly in the groups. The mDCs without CCL19 stimulation migrated in higher amounts in samples of arthritic patients. Cell counts of stimulated DCs showed only slight differences. These results could be generated by a different appearance of the DCs of arthritic patients that might facilitate migration. Further experiments focusing on this aspect should be performed. A possible effect of disruptive factors (age, sex, medication…) needs to be clarified.References:[1]Henes, J.C., et al.,High prevalence of psoriatic arthritis in dermatological patients with psoriasis: a cross-sectional study.Rheumatol Int, 2014.34(2): p. 227-34.[2]Lee, E.B., et al.,Psoriasis risk factors and triggers.Cutis, 2018.102(5s): p. 18-20.[3]Kim, T.G., S.H. Kim, and M.G. Lee,The Origin of Skin Dendritic Cell Network and Its Role in Psoriasis.Int J Mol Sci, 2017.19(1).[4]Veale, D.J. and U. Fearon,The pathogenesis of psoriatic arthritis.Lancet, 2018.391(10136): p. 2273-2284.[5]Ricart, B.G., et al.,Dendritic cells distinguish individual chemokine signals through CCR7 and CXCR4.J Immunol, 2011.186(1): p. 53-61.Acknowledgments:This project was financially supported by Novartis Pharma GmbH.Disclosure of Interests:Sarah Schnitte Grant/research support from: Reaserch grant by Novartis, Alexander Fuchs: None declared, Tanja Funk: None declared, Ann-Christin Pecher: None declared, Daniela Dörfel: None declared, Jörg Henes Grant/research support from: Novartis, Roche-Chugai, Consultant of: Novartis, Roche, Celgene, Pfizer, Abbvie, Sanofi, Boehringer-Ingelheim,

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