A simple, ex vivo phagocytosis assay of Plasmodium vivax merozoites by flow cytometry

Abstract Plasmodium vivax is the most prevalent cause of malaria outside of Africa. P. vivax biology and pathogenesis are still poorly understood. The role of one highly occurring phenotype in particular where infected reticulocytes cytoadhere to noninfected normocytes, forming rosettes, remains unknown. Here, using a range of ex vivo approaches, we showed that P. vivax rosetting rates were enhanced by plasma of infected patients and that total immunoglobulin M levels correlated with rosetting frequency. Moreover, rosetting rates were also correlated with parasitemia, IL-6 and IL-10 levels in infected patients. Transcriptomic analysis of peripheral leukocytes from P. vivax-infected patients with low or moderated rosetting rates identified differentially expressed genes related to human host phagocytosis pathway. In addition, phagocytosis assay showed that rosetting parasites were less phagocyted. Collectively, these results showed that rosette formation plays a role in host immune response by hampering leukocyte phagocytosis. Thus, these findings suggest that rosetting could be an effective P. vivax immune evasion strategy.

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Review for "Diet‐induced microbial autofluorescence confounds flow cytometry of ex vivo isolated fecal microbes"

10.1002/eji.201948087/v1/review2 ◽

2019 ◽

Author(s):

Hyun-Dong Chang

Keyword(s):

Flow Cytometry ◽

Ex Vivo

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

Current Alzheimer Research ◽

10.2174/1567205016666190816130516 ◽

2019 ◽

Vol 16 (8) ◽

pp. 723-731 ◽

Cited By ~ 1

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.

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

Journal for ImmunoTherapy of Cancer ◽

10.1136/jitc-2020-sitc2020.0588 ◽

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.

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Deciphering the temporal heterogeneity of cancer-associated fibroblast subpopulations in breast cancer

Journal of Experimental & Clinical Cancer Research ◽

10.1186/s13046-021-01944-4 ◽

2021 ◽

Vol 40 (1) ◽

Author(s):

Freja Albjerg Venning ◽

Kamilla Westarp Zornhagen ◽

Lena Wullkopf ◽

Jonas Sjölund ◽

Carmen Rodriguez-Cupello ◽

...

Keyword(s):

Breast Cancer ◽

Flow Cytometry ◽

Triple Negative Breast Cancer ◽

Triple Negative ◽

Ex Vivo ◽

Smooth Muscle Actin ◽

Mammary Tissue ◽

Temporal Heterogeneity ◽

Alpha Smooth Muscle Actin ◽

Murine Tumours

Abstract Background Cancer-associated fibroblasts (CAFs) comprise a heterogeneous population of stromal cells within the tumour microenvironment. CAFs exhibit both tumour-promoting and tumour-suppressing functions, making them exciting targets for improving cancer treatments. Careful isolation, identification, and characterisation of CAF heterogeneity is thus necessary for ex vivo validation and future implementation of CAF-targeted strategies in cancer. Methods Murine 4T1 (metastatic) and 4T07 (poorly/non-metastatic) orthotopic triple negative breast cancer tumours were collected after 7, 14, or 21 days. The tumours were analysed via flow cytometry for the simultaneous expression of six CAF markers: alpha smooth muscle actin (αSMA), fibroblast activation protein alpha (FAPα), platelet derived growth factor receptor alpha and beta (PDGFRα and PDGFRβ), CD26/DPP4 and podoplanin (PDPN). All non-CAFs were excluded from the analysis using a lineage marker cocktail (CD24, CD31, CD45, CD49f, EpCAM, LYVE-1, and TER-119). In total 128 murine tumours and 12 healthy mammary fat pads were analysed. Results We have developed a multicolour flow cytometry strategy based on exclusion of non-CAFs and successfully employed this to explore the temporal heterogeneity of freshly isolated CAFs in the 4T1 and 4T07 mouse models of triple-negative breast cancer. Analysing 128 murine tumours, we identified 5–6 main CAF populations and numerous minor ones based on the analysis of αSMA, FAPα, PDGFRα, PDGFRβ, CD26, and PDPN. All markers showed temporal changes with a distinct switch from primarily PDGFRα+ fibroblasts in healthy mammary tissue to predominantly PDGFRβ+ CAFs in tumours. CD26+ CAFs emerged as a large novel subpopulation, only matched by FAPα+ CAFs in abundance. Conclusion We demonstrate that multiple subpopulations of CAFs co-exist in murine triple negative breast cancer, and that the abundance and dynamics for each marker differ depending on tumour type and time. Our results form the foundation needed to isolate and characterise specific CAF populations, and ultimately provide an opportunity to therapeutically target specific CAF subpopulations.

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Quantification of Plasmodium ex vivo drug susceptibility by flow cytometry

Malaria Journal ◽

10.1186/s12936-015-0940-8 ◽

2015 ◽

Vol 14 (1) ◽

Cited By ~ 7

Author(s):

Grennady Wirjanata ◽

Irene Handayuni ◽

Pak Prayoga ◽

Dwi Apriyanti ◽

Ferryanto Chalfein ◽

...

Keyword(s):

Flow Cytometry ◽

Ex Vivo ◽

Drug Susceptibility

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Ex vivo analysis of SIV-infected cells by flow cytometry

Cytometry Part A ◽

10.1002/cyto.a.20960 ◽

2010 ◽

Vol 77A (11) ◽

pp. 1059-1066 ◽

Cited By ~ 3

Author(s):

Matthew R. Reynolds ◽

Shari M. Piaskowski ◽

Kimberly L Weisgrau ◽

Andrea M. Weiler ◽

Thomas C. Friedrich ◽

...

Keyword(s):

Flow Cytometry ◽

Ex Vivo ◽

Infected Cells

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Comparison of a Classical Phagocytosis Assay and a Flow Cytometry Assay for Assessment of the Phagocytic Capacity of Sera from Adults Vaccinated with a Pneumococcal Conjugate Vaccine

Clinical and Diagnostic Laboratory Immunology ◽

10.1128/cdli.8.2.245-250.2001 ◽

2001 ◽

Vol 8 (2) ◽

pp. 245-250 ◽

Cited By ~ 13

Author(s):

Wouter T. M. Jansen ◽

Merja Väkeväinen-Anttila ◽

Helena Käyhty ◽

Moon Nahm ◽

N. Bakker ◽

...

Keyword(s):

Flow Cytometry ◽

Defense Mechanism ◽

Worker Safety ◽

Enzyme Linked Immunosorbent Assay ◽

Phagocytosis Assay ◽

Phagocytic Capacity ◽

Killing Assay ◽

Potential Efficacy ◽

Antibody Titers ◽

Low Sensitivity

ABSTRACT Antibody- and complement-mediated phagocytosis is the main defense mechanism against Streptococcus pneumoniae. A standardized, easy to perform phagocytosis assay for pneumococci would be a great asset for the evaluation of the potential efficacy of (experimental) pneumococcal vaccines. Such an assay could replace the laborious phagocytosis assay of viable pneumococci (classical killing assay). Therefore, a newly developed phagocytosis assay based on flow cytometry (flow assay) was compared with the conventional killing assay and enzyme-linked immunosorbent assay (ELISA), using sera obtained from adults pre- and postvaccination with either a bivalent conjugate, a tetravalent conjugate, or the 23-valent polysaccharide vaccine. Highly significant correlations were observed between flow assay phagocytosis titers, killing assay phagocytosis titers, and ELISA antibody titers for serotype 6B and 23F as well. For serotype 19F, strong correlations were only observed between killing assay and ELISA titers. A potential drawback of the flow assay might be the low sensitivity compared with that of the killing assay. The choice of what assay to use, however, will depend on the objectives of the assay. When speed, easy performance, sample throughput, improved worker safety, absence of influence of antibiotics, and absence of false positives are the major criteria, the flow assay is the method of choice. When higher sensitivity is the major requirement, the classical killing assay should be used.

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Applications of Flow Cytometry to Clinical Microbiology

Clinical Microbiology Reviews ◽

10.1128/cmr.13.2.167 ◽

2000 ◽

Vol 13 (2) ◽

pp. 167-195 ◽

Cited By ~ 67

Author(s):

Alberto Álvarez-Barrientos ◽

Javier Arroyo ◽

Rafael Cantón ◽

César Nombela ◽

Miguel Sánchez-Pérez

Keyword(s):

Flow Cytometry ◽

Clinical Microbiology ◽

Ex Vivo ◽

Analytical Techniques ◽

Clinical Samples ◽

Clinical Microbiology Laboratory ◽

Commercial Kits ◽

Antimicrobial Treatments ◽

Near Future

SUMMARY Classical microbiology techniques are relatively slow in comparison to other analytical techniques, in many cases due to the need to culture the microorganisms. Furthermore, classical approaches are difficult with unculturable microorganisms. More recently, the emergence of molecular biology techniques, particularly those on antibodies and nucleic acid probes combined with amplification techniques, has provided speediness and specificity to microbiological diagnosis. Flow cytometry (FCM) allows single- or multiple-microbe detection in clinical samples in an easy, reliable, and fast way. Microbes can be identified on the basis of their peculiar cytometric parameters or by means of certain fluorochromes that can be used either independently or bound to specific antibodies or oligonucleotides. FCM has permitted the development of quantitative procedures to assess antimicrobial susceptibility and drug cytotoxicity in a rapid, accurate, and highly reproducible way. Furthermore, this technique allows the monitoring of in vitro antimicrobial activity and of antimicrobial treatments ex vivo. The most outstanding contribution of FCM is the possibility of detecting the presence of heterogeneous populations with different responses to antimicrobial treatments. Despite these advantages, the application of FCM in clinical microbiology is not yet widespread, probably due to the lack of access to flow cytometers or the lack of knowledge about the potential of this technique. One of the goals of this review is to attempt to mitigate this latter circumstance. We are convinced that in the near future, the availability of commercial kits should increase the use of this technique in the clinical microbiology laboratory.

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A new Plasmodium vivax reference sequence with improved assembly of the subtelomeres reveals an abundance of pir genes

Wellcome Open Research ◽

10.12688/wellcomeopenres.9876.1 ◽

2016 ◽

Vol 1 ◽

pp. 4 ◽

Cited By ~ 56

Author(s):

Sarah Auburn ◽

Ulrike Böhme ◽

Sascha Steinbiss ◽

Hidayat Trimarsanto ◽

Jessica Hostetler ◽

...

Keyword(s):

South America ◽

Plasmodium Vivax ◽

Sequence Data ◽

Ex Vivo ◽

Vital Role ◽

Asia Pacific ◽

Reference Sequence ◽

Manual Curation ◽

Illumina Sequence

Plasmodium vivax is now the predominant cause of malaria in the Asia-Pacific, South America and Horn of Africa. Laboratory studies of this species are constrained by the inability to maintain the parasite in continuous ex vivo culture, but genomic approaches provide an alternative and complementary avenue to investigate the parasite’s biology and epidemiology. To date, molecular studies of P. vivax have relied on the Salvador-I reference genome sequence, derived from a monkey-adapted strain from South America. However, the Salvador-I reference remains highly fragmented with over 2500 unassembled scaffolds. Using high-depth Illumina sequence data, we assembled and annotated a new reference sequence, PvP01, sourced directly from a patient from Papua Indonesia. Draft assemblies of isolates from China (PvC01) and Thailand (PvT01) were also prepared for comparative purposes. The quality of the PvP01 assembly is improved greatly over Salvador-I, with fragmentation reduced to 226 scaffolds. Detailed manual curation has ensured highly comprehensive annotation, with functions attributed to 58% core genes in PvP01 versus 38% in Salvador-I. The assemblies of PvP01, PvC01 and PvT01 are larger than that of Salvador-I (28-30 versus 27 Mb), owing to improved assembly of the subtelomeres. An extensive repertoire of over 1200 Plasmodium interspersed repeat (pir) genes were identified in PvP01 compared to 346 in Salvador-I, suggesting a vital role in parasite survival or development. The manually curated PvP01 reference and PvC01 and PvT01 draft assemblies are important new resources to study vivax malaria. PvP01 is maintained at GeneDB and ongoing curation will ensure continual improvements in assembly and annotation quality.

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