scholarly journals Delays during PBMC isolation have a moderate effect on yield, but severly compromise cell viability

Author(s):  
Tanja Golke ◽  
Patrick Mucher ◽  
Patricia Schmidt ◽  
Astrid Radakovics ◽  
Manuela Repl ◽  
...  

Background: Peripheral blood mononuclear cells (PMBCs) are a versatile material for clinical routine as well as for research projects. However, their isolation via density gradient centrifugation is still time-consuming. When samples are taken beyond usual laboratory handling times, it may sometimes be necessary to pause the isolation process. Our aim was to evaluate the impact of delays up to 48 hours after the density gradient centrifugation on PBMC yield, purity and viability. Methods: PBMCs were isolated from samples of 20 donors, either with BD Vacutainer CPT tubes (CPT) or with the standard Ficoll method. Isolation was paused after initial density gradient centrifugation for 0, 24, or 48 hours. PBMC yield, purity and viability were compared. Results: The yield did not change significantly over time when CPT were used (55%/52%/47%), but did after isolation with the standard method (62%/40%[p<0.0001]/53%[p<0.01]). Purity was only affected if CPT were used (95%/93%[p=n.s./92%[p<0.05] vs. 97% for all time points with standard method). Whereas viable PBMCs decreased steadily for CPT isolates (62%/51%[p<0.001]/36%[p<0.0001]), after standard Ficoll gradient isolation, cell apoptosis was more pronounced already after 24h delay, and viability did not further decrease after 48h (64%/44%[p<0.0001]/40%[p<0.0001]). Conclusions: In conclusion, our data suggests that post-centrifugation delays of up to 48h might have only a minor effect on cell yield and purity. However, at the same time, a relevant decrease in cell viability was observed, which could be partially compensated by the use of CPT if the isolation was resumed latest the day after blood withdrawal.

2021 ◽  
Vol 12 ◽  
Author(s):  
Judith Schenz ◽  
Manuel Obermaier ◽  
Sandra Uhle ◽  
Markus Alexander Weigand ◽  
Florian Uhle

Elucidating the mechanisms contributing to the dysregulated host response to infection as part of the syndrome is a current challenge in sepsis research. Peripheral blood mononuclear cells are widely used in immunological studies. Density gradient centrifugation, a common method, is of limited use for blood drawn from patients with sepsis. A significant number of low-density granulocytes co-purify contributing to low purity of isolated peripheral blood mononuclear cells. Whole blood anticoagulated with lithium heparin was drawn from patients with sepsis (n=14) and healthy volunteers (n=11). Immediately after drawing, the plasma fraction was removed and PBMC were isolated from the cellular fraction by density gradient centrifugation. Samples derived from patients with sepsis were subsequently incubated with cluster of differentiation 15 MicroBeads and granulocytes were depleted using magnetic-activated cell sorting. Core cellular functions as antigen presentation and cytokine secretion were analyzed in cells isolated from healthy volunteers (n=3) before and after depletion to confirm consistent functionality. We report here that depleting CD15+ cells after density gradient centrifugation is a feasible way to get rid of the low-density granulocyte contamination. Afterwards, the purity of isolated, functionally intact peripheral blood mononuclear cells is comparable to healthy volunteers. Information on the isolation purity and identification of the containing cell types are necessary for good comparability between different studies. Depletion of CD15+ cells after density gradient centrifugation is an easy but highly efficient way to gain a higher quality and more reliability in studies using peripheral blood mononuclear cells from septic patients without affecting the functionality of the cells.


Author(s):  
Sudeep Nagaraj ◽  
Shubha Nivargi ◽  
Leelavathy Nanjappa ◽  
Jagadish Tavarekere Venkataravanappa

One step centrifugation procedure used commonly for separation of blood cells is the ficoll gradient centrifugation. In this method, after centrifugation, the peripheral blood mononuclear cells (PBMCs) are located on the top of the separation fluid, whereas other blood cells erythrocytes and granulocytes sediment to the bottom. In the present study 75% of lymphocyte suspension could be separated by using a one-step density gradient centrifugation of sodium heparin blood with Sucrose. Sucrose was diluted into different concentrations using miliQ water (10%, 20%, 30%, 40%, 50%, 60%,70%, 80%, 90%, 100%,). 4 mL of diluted blood was layered on 4 mL of each sucrose solution and centrifuged for 45 minutes at 1000 rpm. Clear separation of PBMCs could be observed in solution with 40% sucrose. The separated PBMCs were analysed in haeme analyser which showed 75% lymphocytes, 23% monocytes and 2% of other cells.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Maria D. I. Manunta ◽  
Giuseppe Lamorte ◽  
Francesca Ferrari ◽  
Elena Trombetta ◽  
Mario Tirone ◽  
...  

AbstractSARS-CoV-2 virus infection is responsible for coronavirus disease (COVID-19), which is characterised by a hyperinflammatory response that plays a major role in determining the respiratory and immune-mediated complications of this condition. While isolating peripheral blood mononuclear cells (PBMCs) from whole blood of COVID-19 patients by density gradient centrifugation, we noticed some changes in the floating properties and in the sedimentation of the cells on density medium. Investigating this further, we found that in early phase COVID-19 patients, characterised by reduced circulating lymphocytes and monocytes, the PBMC fraction contained surprisingly high levels of neutrophils. Furthermore, the neutrophil population exhibited alterations in the cell size and in the internal complexity, consistent with the presence of low density neutrophils (LDNs) and immature forms, which may explain the shift seen in the floating abilities and that may be predictive of the severity of the disease. The percentage of this subset of neutrophils found in the PBMC band was rather spread (35.4 ± 27.2%, with a median 28.8% and IQR 11.6–56.1, Welch’s t-test early phase COVID-19 versus blood donor healthy controls P < 0.0001). Results confirm the presence of an increased number of LDNs in patients with early stage COVID-19, which correlates with disease severity and may be recovered by centrifugation on a density gradient together with PBMCs.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yanli Li ◽  
Enric Mateu ◽  
Ivan Díaz

The use of frozen peripheral blood mononuclear cells (PBMC) is common in immunological studies. The impact of freezing PBMC has been assessed using human and mice cells, but little information is available regarding domestic animals. In the present study, the phenotype and functionality of frozen porcine PBMC were examined. In a preliminary experiment, three freezing media: fetal bovine serum plus 10% dimethyl sulfoxide, PSC cryopreservation kit, and Cryostor CS10, were compared regarding the preservation of cell viability and the response of PBMC to mitogens after thawing. After being stored one month in liquid nitrogen, cell viability was above 89% for all freezing media. The ELISPOT IFN-gamma (IFN-γ) results in response to PHA and of IgG ELISPOT in response to R848+IL-2 were similar to those obtained using fresh PBMC. In the second set of experiments, PBMC were obtained from five pigs vaccinated against Porcine reproductive and respiratory syndrome virus (PRRSV) and then frozen using Cryostor CS10. Recovered cells were phenotyped by flow cytometry using anti-CD3, CD4, CD8, and CD21 antibodies and were used to assess the PRRSV-specific responses in a proliferation experiment, an IFN-γ ELISPOT, and an IgG ELISPOT, and compared to the results obtained with fresh cells. The antigen-specific responses of frozen cells were significantly (p&lt;0.05) impaired in the proliferation assay, particularly for CD4/CD8 double-positive T-cells and for CD21+ cells. Freezing resulted in decreased proliferation when Con A, but not PHA, was used. In ELISPOT, cryopreservation resulted in a decreased frequency of IFN-γ-secreting cells in response to PRRSV (p&lt;0.05) but the response to PHA was not affected. No differences were observed in the IgG ELISPOT after polyclonal activation. Taken together, cryopreservation of porcine PBMC had a significant impact on the magnitude of recall antigen responses and therefore, it may affect the response of effector/memory cells but seems not to have a major impact on naïve T-cells. These results may help to the better use of frozen porcine PBMC, and to the interpretation of the results obtained from them.


2018 ◽  
Vol 64 (2) ◽  
pp. 83-90 ◽  
Author(s):  
Georgiana Mihaela Şerban ◽  
Ion Bogdan Mănescu ◽  
Doina Ramona Manu ◽  
Minodora Dobreanu

Abstract Objective: Peripheral blood mononuclear cells (PBMC) are extremely important in the body’s immune response. Their isolation represents a major step in many immunological experiments. In this two phase study, we aimed to establish an optimum protocol for PBMC isolation by density-gradient centrifugation. Methods: During Phase-1, we compared two commercially available PBMC isolation protocols, Stemcell Technologies (ST) and Miltenyi Biotec (MB), in terms of PBMC recovery and purity. Twelve blood samples were assigned to each protocol. Each sample was divided in three subsamples of 1ml, 2ml and 3ml in order to assess the influence of blood sample volume on isolation performance. During Phase-2, a hybrid protocol was similarly tested, processing six blood samples. Additionally, we performed a flow cytometric analysis using an Annexin-V/Propidium-Iodide viability staining protocol. Results: Phase-1 results showed that, for all subsample volumes, ST had superior PBMC recovery (mean values: 56%, 80% and 87%, respectively) compared to MB (mean values: 39%, 54% and 43%, respectively). However, platelet removal was significantly higher for MB (mean value of 96.8%) than for ST (mean value of 75.2%). Regarding granulocyte/erythrocyte contamination, both protocols performed similarly, yielding high purity PBMC (mean values: 97.3% for ST and 95.8% for MB). During Phase-2, our hybrid protocol yielded comparable results to MB, with an average viability of 89.4% for lymphocytes and 16.9% for monocytes. Conclusions: ST yields higher cell recovery rates and MB excels at platelet removal, while the hybrid protocol is highly similar to MB. Both cell recovery and viability increase with blood sample volume.


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