Determining reference ranges for lymphocyte proliferation responses to phytohemagglutinin and Bacillus Calmette-Guérin in Iranian children.

PURPOSE: To establish reference ranges (RRs) for stimulation index of T cell proliferation triggered by phytohemagglutinin (PHA-SI) and Bacillus Calmette-Guérin (BCG-SI). METHODS: This study investigated data from 359 healthy children and 35 patients with cellular immunodeficiency as positive controls (2010-2021). We applied a colorimetric-based method (BrdU) to measure proliferation and determine the RRs at the 2.5th and 97.5th percentiles (95% confidence intervals). A cross-validation approach was performed. RESULTS: In healthy controls, the RRs for PHA-SI and BCG-SI ranged between 3 and 5.2 and 2.52 to 5.2, respectively. PHA-SI and BCG-SI were in Severe Combined Immunodeficiency (SCID) patients from 1.2 to 2.5 and 0 to 2, while in Mendelian susceptibility to mycobacterial diseases (MSMD) patients, 2.53 to 4.5 and 0.74 to 2.2, respectively. The thresholds' accuracy was checked for testing reference intervals with diagnostic effects. CONCLUSION: This study establishes PHA-SI and BCG-SI reference ranges to aid in diagnosing and treating congenital immunodeficiency diseases.

Phytohemagglutinin from Phaseolus vulgaris enhances the lung cancer cell chemotherapy sensitivity by changing cell membrane permeability.

Chemotherapy is still a prevalent strategy for clinical lung cancer treatment. However, the inevitable emerged drug resistance has become a great hurdle to therapeutic effect. Studies have demonstrated that the primary cause of drug resistance is a decrease in the chemotherapeutic medicine concentration. Several lectins have been confirmed to be effective as chemotherapy adjuvants, enhancing the anti-tumor effects of chemotherapy drugs. Here, we combined phytohemagglutinin (PHA), which has been reported possess anti-tumor effects, with chemotherapy drugs Cisplatin (DDP) and Adriamycin (ADM) on lung cancer cells to detect the sensitivities of PHA as a chemotherapy adjuvant. Our results demonstrated that the PHA significantly enhanced the sensitivity of lung cancer cells to DDP and ADM, and Western blot showed that PHA combined with DDP or ADM enhance cytotoxic effects by inhibiting autophagy and promoting apoptosis. More importantly, we found PHA enhanced the chemotherapeutic drugs cytotoxicity by changing the cell membrane to increase the intracellular chemotherapeutic drugs concentration. Besides, the combination of PHA and ADM increased the ADM concentration in the multidrug-resistant strain A549-R cells and achieved the drug sensitization effect. Our results suggest that PHA combined with chemotherapy can be applied in the treatment of lung cancer cells and lung cancer multidrug-resistant strains, and provide a novel strategy for clinical tumor chemotherapy and a new idea to solve the problem of drug resistance in clinical lung cancer.

Nicotinic acid modulates microglial TREM-2 gene in Phytohaemagglutinin-Induced in vitro model of Alzheimer's disease like pathology.

Alzheimer's disease (AD) is a multifactorial,neurodegenerative disorder linked withextracellular amyloid beta (Aß) plaques deposition and formation of intracellular neurofibrillary tangles (NFTs). Currently, no effective therapies are available to cure AD. Neuroinflammation isa well-known hallmark in the onset and advancement of AD and triggering receptor expressed on myeloid cells-2 (TREM-2), a microglial gene, is responsible for regulating inflammatory responses and clearance of cellular debris. Loss of TREM-2functionincreases neuroinflammation associated expression of pro-inflammatory markersthus resultingin reduced clearance of Aß that further aid in disease progression.Therefore, targeting neuroinflammation is a good therapeutic approach for AD. This study aimed to determine the neuroprotective effect of nicotinic acid (NA) in vitro model of AD-like pathology induced in F-98 cell line using Phytohemagglutinin (PHA). MTT assay was employed for checking the cell viability as well as the proliferation of the cells following treatment with NA. PHA at the concentration of 10 µg/mL produces maximum plaques. The neuroprotective effect of NA was next evaluated against PHA-induced plaques and it was observed that NA reverses the damages induced by PHA i.e., by inhibiting the clustering of the cells and replacing the damaged cells with the new ones. Further, NA also increased the expression of TREM-2/DAP-12 with parallel decreased in the expression of IL-1ß, TNF-α and iNOS. It also successfully altered disease associated ADAM-10 and BACE-1 compared to PHA control. These findings suggest that NA might be considered as a good therapeutic candidate for the treatment of neurodegenerative disorders like AD.

Recombinant Phaseolus vulgaris phytohemagglutinin L-form expressed in the Bacillus brevis exerts in vitro and in vivo anti-tumor activity through potentiation of apoptosis and immunomodulation.

Leukocyte phytohemagglutinin (PHA-L) is a tetrameric isomer of phytohemagglutinin (PHA) purified from the red kidney bean (Phaseolus vulgaris) and is a well-known human lymphocyte mitogen. Due to its antitumor and immunomodulatory effects, PHA-L may serve as a potential antineoplastic agent in future cancer therapeutics. However, various negative consequences of PHA have been reported in the literature as a result of the restricted acquisition methods, including oral toxicity, hemagglutinating activity, and immunogenicity. There is a critical need to explore a new method to obtain PHA-L with high purity, high activity and low toxicity. In this report active recombinant PHA-L protein was successfully prepared by Bacillus brevius expression system, and the antitumor and immunomodulatory activities of recombinant PHA-L were characterized by in vitro and in vivo experiments. The results showed that recombinant PHA-L protein had stronger antitumor effect, and its anti-tumor mechanism was realized through direct cytotoxicity and immune regulation. Importantly, compared with natural PHA-L, the recombinant PHA-L protein showed the lower erythrocyte agglutination toxicity in vitro and immunogenicity in mice. Altogether, our study provides a new strategy and important experimental basis for the development of drugs with dual effects of immune regulation and direct antitumor activity.

Influence of Paleobacteria on the Proliferative Activity of Human Lymphocytes In Vitro.

When testing the proliferative activity of 14 strains of permafrost microorganisms in the reaction of blast transformation of human lymphocytes in vitro, a strain (Alcaligenes sp.) with mitogen properties was isolated (20-fold increase in the rate of lymphocyte proliferation in comparison with the control). Four strains activated lymphocyte proliferation by 3-9 times in comparison with the control. Three strains produced substances with cytostatic properties and reduced proliferation activity by 33-43% and one strain (Bacillus sp.) almost completely suppressed phytohemagglutinin-induced lymphocyte proliferation. These data indicate that strains with a unique immunobiological potential are concentrated in the population of permafrost microorganisms that have undergone rigorous evolutionary selection.

Bladder Cancer Cells Interaction with Lectin-Coated Surfaces under Static and Flow Conditions.

Aberrant expression of glycans, i.e., oligosaccharide moiety covalently attached to proteins or lipids, is characteristic of various cancers, including urothelial ones. The binding of lectins to glycans is classified as molecular recognition, which makes lectins a strong tool for understanding their role in developing diseases. Here, we present a quantitative approach to tracing glycan-lectin interactions in cells, from the initial to the steady phase of adhesion. The cell adhesion was measured between urothelial cell lines (non-malignant HCV29 and carcinoma HT1376 and T24 cells) and lectin-coated surfaces. Depending on the timescale, single-cell force spectroscopy, and adhesion assays conducted in static and flow conditions were applied. The obtained results reveal that the adhesion of urothelial cells to two specific lectins, i.e., phytohemagglutinin-L and wheat germ agglutinin, was specific and selective. Thus, these lectins can be applied to selectively capture, identify, and differentiate between cancer types in a label-free manner. These results open up the possibility of designing lectin-based biosensors for diagnostic or prognostic purposes and developing strategies for drug delivery that could target cancer-associated glycans.

Immunological evaluation of patients with Alzheimer's disease based on mitogen-stimulated cytokine productions and mitochondrial DNA indicators.

BACKGROUND: Based on its objective characteristics, laboratory markers have always been the research direction of clinical diagnosis and assessment of mental disorders including Alzheimer's disease. METHODS: MTT Colorimetric Assay, ELISA, and quantitative PCR were used to investigate the responsiveness of peripheral blood mononuclear cells (PBMCs) to mitogen Lipopolysaccharides (LPS) and Phytohemagglutinin (PHA), PBMCs genomic methylation and hydroxymethylation levels, nuclear DNA and mitochondrial DNA damage, respiratory chain enzyme activities, and circulating cell-free mitochondrial DNA levels were detected in 90 patients with Alzheimer's disease. RESULTS: In the Alzheimer's disease group, LPS stimulated PBMCs viability, TNF-α secretion, PHA stimulated IL-10 secretion, genomic DNA methylation levels, circulating cell-free mitochondrial DNA copies, citrate synthase activity were reduced compared to the control; while the LPS stimulated PBMCs IL-1α secretion, PHA stimulated IL-1α and IFN-γ secretion, plasma IL-6 and TNF-α, mitochondrial DNA damages were increased compared to the control. CONCLUSIONS: The reactivity of peripheral blood mononuclear cells to mitogens, mitochondrial DNA integrity characteristics, and cell-free mitochondrial DNA copies may be used as candidate laboratory biomarkers to help clinical management of Alzheimer's disease.

Impaired T-cell response to phytohemagglutinin (PHA) in tuberculosis patients is associated with high IL-6 plasma levels and normalizes early during anti-mycobacterial treatment.

PURPOSE: Human tuberculosis is characterized by immunopathology that affects T-cell phenotype and functions. Previous studies found impaired T-cell response to phytohemagglutinin (PHA) in patients with acute tuberculosis. However, the influence of disease severity, affected T-cell subsets, and underlying mechanisms remain elusive. METHODS: Here we investigated PHA-induced and antigen-specific T-cell effector cytokines in tuberculosis patients (n = 55) as well as in healthy asymptomatic contacts (n = 32) from Ghana. Effects of Mycobacterium (M.) tuberculosis sputum burden and treatment response were analyzed and compared during follow-up. Finally, cytokine characteristics of the aberrant plasma milieu in tuberculosis were analyzed as a potential cause for impaired PHA response. RESULTS: PHA-induced IFN-γ expression was significantly lower in sputum-positive tuberculosis patients as compared to both, contacts and paucibacillary cases, and efficiently discriminated the study groups. T-cell responses to PHA increased significantly early during treatment and this was more pronounced in tuberculosis patients with rapid treatment response. Analysis of alternative cytokines revealed distinct patterns and IL-22, as well as IL-10, showed comparable expression to IFN-γ in response to PHA. Finally, we found that high IL-6 plasma levels were strongly associated with impaired IFN-γ and IL-22 response to PHA. CONCLUSION: We conclude that impaired T-cell response to PHA stimulation in acute tuberculosis patients (i) was potentially caused by the aberrant plasma milieu, (ii) affected differentially polarized T-cell subsets, (iii) normalized early during treatment. This study shed light on the mechanisms of impaired T-cell functions in tuberculosis and yielded promising biomarker candidates for diagnosis and monitoring of treatment response.

Lymphocyte Transformation Test Based on Lymphocyte Changes Observed by a Hematology Analyzer before and after Phytohemagglutinin Stimulation.

Objective: The lymphocyte transformation test is a classical test for the detection of cellular immune function and is based on subjective judgment. In this study, we have established an objective novel lymphocyte transformation test using the hematology analyzer to observe lymphocyte transformation. Methods: Whole blood cells were cultured using a whole blood method with a lymphocyte culture medium; phytohemagglutinin was used to stimulate the experimental samples, and control was set up at the same time. After the whole blood cells were cultured, the number of lymphocytes in the two groups was observed using a hematology analyzer, and the conversion rate was calculated. The new method was used to observe differences in lymphocyte conversion in the peripheral blood of patients with hematopathy and healthy persons. Results: There were significant differences between the stimulated peripheral blood group and the blank group. The transformation rate of peripheral blood lymphocytes in patients with hematopathy was significantly lower than that in healthy persons; the difference was statistically significant (P < 0.05). Conclusion: Lymphocyte transformation can be observed using a hematology analyzer. The lymphocyte transformation test that is based on the determination of lymphocyte count by a hematology analyzer has important clinical value.

Evaluation of T Cell Proliferation Using CFSE Dilution Assay: A Comparison between Stimulation with PHA and Anti-CD3/Anti-CD28 Coated Beads.

A decrease in T cell count or reduced T cell function can be indicative of T cell immunodeficiency. In the present study, T-cell function was assessed using Carboxyfluorescein diacetate succinimidyl ester (CFSE) dilution test after stimulation with commonly used Phytohaemagglutinin (PHA) or anti-CD3/anti-CD28 coated beads in pediatric patients with recurrent infections. Seven infants with recurrent infections and seven sex/age-matched healthy infants were included in this study. A blood cell count, immunophenotyping, and serum immunoglobulin level were performed. The proliferation of T cells was also assessed with CFSE dilution after stimulation with PHA or anti-CD3/anti-CD28 coated beads.  This study showed increased IgA, IgG, and IgM levels in patients compared to the controls. In contrast to the controls, the immunophenotyping results showed a significant decline in the number of CD4+ T cells in patients. Although there was no difference in CD3+ T cell proliferation between patients and controls, the CD4+ and CD8+ T cell proliferation rates were significantly decreased in patients when stimulated with PHA. As a mitogen with the potential for maximum proliferation of T cells, PHA is better able to distinguish between patients with recurrent infections and controls than anti-CD3/anti-CD28, which mimics only the TCR pathway for stimulation of T cells.

Preparation of a novel monoclonal antibody against active components of PHA-L from Phaseolus vulgaris and its functional characteristics.

BACKGROUND: Leukocyte phytohemagglutinin (PHA-L), derived from the L4 tetramer of PHA, has been frequently employed as a mitogen to induce T lymphocyte proliferation in vitro. The biological application of PHA-L in cancer diagnosis and treatment has gained traction in recent years. However, it has been noted that PHA-L obtained using traditional procedures has a massive amount of impurities or toxic components, which interfere with the activity of PHA-L. Preparation of a monoclonal antibody against active PHA-L is a significant tool for studying PHA-L's function and therapeutic potential. RESULTS: We successfully prepared monoclonal antibodies against the active components of PHA-L based on the whole PHA-L protein as an antigen, and found that monoclonal antibody 3C1C6G11 can be employed in western blot, immunofluorescence, and immunohistochemistry detection. Importantly, preliminary result shows that the mAb 3C1C6G11 may prevent PHA-L-induced cell aggregation and AICD (activation-induced cell death). CONCLUSIONS: The monoclonal antibody mAb 3C1C6G11 prepared in this study can be used as an effective tool for detecting PHA-L active components, investigating PHA-L's function and antineoplastic application.

Functional in vitro models of the inhibitory effect of adipose tissue-derived stromal cells on lymphocyte proliferation: Improved sensitivity and quantification through flow cytometric analysis.

As the interest in cell-based therapies continue to increase, so does the need for assays detailing potency and providing platforms for identifying mechanisms of action. For most clinical implications of mesenchymal stromal cells, the immunomodulatory effect is crucial. While the suppressive potential on lymphocyte proliferation is well-described in literature, reproducible and standardized assays to document and quantify it varies from research group to research group and between methodologies. The aim of the present study was to utilize flowcytometry to quantify proliferation and identify measurements to increase the assay sensitivity to treatment with adipose tissue-derived stromal cells (ASC). Lymphocyte proliferation was induced by the unspecific mitogen phytohemagglutinin or by alloreactivity towards an irradiated donor in a mixed lymphocyte reaction. Addition of ASC did not change the composition of T cells, B cells, NK cells, NKT cell types considerably; likewise, no increases in proliferation were observed upon inclusion of ASC, demonstrating that ASC does not evoke an additive response. On the contrary, the suppressive effect of ASC was documented. By applying different gating strategies and curve fitting, the sensitivity was increased, and dose-response relationships established. Flow cytometric evaluation allows for more detailed identification of the lymphocytes affected by ASC and constitute a significant asset in future unraveling of modes and mechanisms of action, as well as quantification of potency.

Long-term sex-dependent inflammatory response of adult frogs to ammonium exposure during the larval stage.

Among others, the global change involves a worldwide increase in cropland area, with the concomitant rise in nitrogenous fertilizer supplementation and species range alterations, including parasites and pathogens. As most animals rely on their immune systems against these infectious agents, studying the potential effects of nitrogenous compounds on animal immune response is vital to understand their susceptibility to infections under these altered circumstances. Being subjected to an alarming process of global declines, amphibians are the object of particular attention, given their sensitivity to these compounds, especially to ammonium. Moreover, whereas adults can actively avoid polluted patches, larvae are confined within their waterbodies, thus exposed to contaminants in it. In this work, we test whether chronic exposure to a sublethal dose of ammonium during the larval stage of Pelophylax perezi frogs, released from all contamination after metamorphosis, leads to impaired inflammatory response to phytohemagglutinin in adults. We also test whether such a response differs between agrosystem individuals as compared with conspecifics from natural habitats. We found negative carryover effects of chronic exposure of larvae to ammonium on adult inflammatory response, which could imply a greater susceptibility to pathogens and parasites. However, this damage is only true for males, which, according to the immunocompetence handicap hypothesis, could be a consequence of a testosterone-triggered impairment of male immune function. In disagreement with our prediction, however, we detected no differences in the inflammatory response of agrosystem frogs to phytohemagglutinin as compared with natural habitat conspecifics.

An updated view into the cell cycle kinetics of human T lymphocytes and the impact of irradiation.

Even though a detailed understanding of the proliferative characteristics of T lymphocytes is imperative in many research fields, prior studies have never reached a consensus on these characteristics, and on the corresponding cell cycle kinetics specifically. In this study, the general proliferative response of human T lymphocytes to phytohaemagglutinin (PHA) stimulation was characterized using a carboxyfluorescein succinimidyl ester-based flow cytometric assay. We were able to determine when PHA-stimulated T lymphocytes complete their first division, the proportion of cells that initiate proliferation, the subsequent division rate of the cells, and the impact of irradiation on these proliferative properties. Next, we accurately visualized the cell cycle progression of dividing T lymphocytes cultured in whole blood using an adapted 5-ethynyl-2'-deoxyuridine pulse-chase method. Furthermore, through multiple downstream analysis methods, we were able to make an estimation of the corresponding cell cycle kinetics. We also visualized the impact of X-rays on the progression of the cells through the cell cycle. Our results showed dose-dependent G2 arrest after exposure to irradiation, and a corresponding delay in G1 phase-entry of the cells. In conclusion, utilizing various flow cytometric assays, we provided valuable information on T lymphocyte proliferation characteristics starting from first division to fully dividing cells.

Reduced Expression of Natural Killer Cell-Related Activating Receptors by Peripheral Blood Mononuclear Cells from Patients with Breast Cancer and Their Improvement by Zoledronic Acid.

BACKGROUND/AIM: Natural killer (NK) cell receptors affect the NK cell-mediated elimination of malignant cells. In this experimental study the effect of Zoledronic acid (ZOL) was investigated on the expression of NK activating- (NKP46 and NKG2D) and inhibitory (KIR2DL1) receptors by Phytohaemagglutinin (PHA)-stimulated peripheral blood mononuclear cells (PBMCs) from breast cancer (BC) patients. MATERIALS AND METHODS: Peripheral blood mononuclear cell-extracted RNA from thirty breast cancer women and twenty-five healthy subjects was analyzed for gene expression of NKP46, NKG2D and KIR2DL1 using real time-PCR. Then, the PBMCs from BC patients were cultured in the presence of PHA with 5 µg/ml, 10 or 20 µg/ml of ZOL for 32 hours and expression of the aforementioned receptors was determined. RESULTS: Expression of NKP46, NKG2D and NKP46/KIR2DL1 ratio in BC women were lower than healthy group (P<0.01, P<0.04 and P<0.05, respectively). NKP46 expression was up-regulated by PHA-stimulated PBMCs treated with 10 µg/ml and 20 µg/ml of ZOL compared with PHA-stimulated cultures (P<0.01 and P<0.05, respectively). NKG2D expression remarkably increased by PHA-stimulated cultures treated with 5 µg/ml, 10 µg/ml and 20 µg/ml of ZOL compared with PHA-stimulated cultures (P<0.05 and P<0.02 and P<0.04, respectively). CONCLUSION: Expression of NK cell-related activating receptors decreased in BC patients. ZOL can improve the expression of NK activating receptors.

Immunological factors, but not clinical features, predict visceral leishmaniasis relapse in patients co-infected with HIV.

Visceral leishmaniasis (VL) has emerged as a clinically important opportunistic infection in HIV patients, as VL/HIV co-infected patients suffer from frequent VL relapse. Here, we follow cohorts of VL patients with or without HIV in Ethiopia. By the end of the study, 78.1% of VL/HIV-but none of the VL patients-experience VL relapse. Despite a clinically defined cure, VL/HIV patients maintain higher parasite loads, lower BMI, hepatosplenomegaly, and pancytopenia. We identify three immunological markers associated with VL relapse in VL/HIV patients: (1) failure to restore antigen-specific production of IFN-γ, (2) persistently lower CD4+ T cell counts, and (3) higher expression of PD1 on CD4+ and CD8+ T cells. We show that these three markers, which can be measured in primary hospital settings in Ethiopia, combine well in predicting VL relapse. The use of our prediction model has the potential to improve disease management and patient care.

Cytokine producing ability of peripheral blood cells from COVID-19 patients after unspecific in vitro stimulation.

OBJECTIVE AND DESIGN: Perturbations of peripheral T cell homeostasis and dysregulation of the immune response to SARS-CoV-2, especially in severely ill patients, were observed. The aim of this study was to analyze the cytokine producing ability of peripheral blood cells from severely ill COVID-19 patients upon non-specific in vitro stimulation with phytohemagglutinin (PHA). Possible associations of cytokine levels with patients' age and gender, glucocorticosteroid therapy, as well as the trend of the inflammatory process at the time of sampling (increased or decreased) were also analyzed. SUBJECTS AND METHODS: The study included 23 COVID-19 patients and 17 healthy control subjects. The concentrations of selected Th1/Th2/Th9/Th17/Th22 cytokines were determined using a multi-analyte flow assay kit. RESULTS: Our results showed that peripheral blood cells from severely ill COVID-19 patients had a much reduced ability to produce cytokines in comparison to healthy controls. When inflammation was raised, blood cells produced more IL-6 and IL-17, which led to increases of some Th17/Th1 and Th17/Th2 ratios, skewing towards the Th17 type of response. The methylprednisolone used in the treatment of patients with COVID-19 influences the production of several cytokines in dose dependent manner. CONCLUSION: Our results indicate that the stage of the inflammatory process at the time of sampling and the dose of the applied glucocorticosteroid therapy might influence cytokine producing ability upon non-specific stimulation of T cells in vitro.

Liposomal phytohemagglutinin: In vivo T-cell activator as a novel pan-cancer immunotherapy.

Immunotherapy is an attractive approach for treating cancer. T-cell engagers (TCEs) are a type of immunotherapy that are highly efficacious; however, they are challenged by weak T-cell activation and short persistence. Therefore, alternative solutions to induce greater activation and persistence of T cells during TCE immunotherapy is needed. Methods to activate T cells include the use of lectins, such as phytohemagglutinin (PHA). PHA has not been used to activate T cells in vivo, for immunotherapy, due to its biological instability and toxicity. An approach to overcome the limitations of PHA while also preserving its function is needed. In this study, we report a liposomal PHA which increased PHA stability, reduced toxicity and performed as an immunotherapeutic that is able to activate T cells for the use in future cancer immunotherapies to circumvent current obstacles in immunosuppression and T-cell exhaustion.

[Effects of water level variations on survival, morphological phenotype and responsiveness of tadpoles to phytohemagglutinin]. / æ°´ä½å˜åŒ–å½±å“èŒèšªå­˜æ´»ã€å½¢æ€è¡¨åž‹å’Œæ¤ç‰©è¡€å‡ç´ ååº”.

To investigate the responses of morphological and physiological characteristics in tadpoles of Pelophylax nigromaculatus to various water levels, a total of 480 tadpoles with similar sizes were treated with rapid, moderate and slow desiccation. Both the metamorphosis duration and average metamorphosis survival rate of specific developmental stages were counted. Their body and internal organ sizes, as well as the responsiveness to phytohemagglutinin (PHA-P) of froglets were measured after complete metamorphosis. The results showed that the metamorphosis duration of tadpoles in the control group was the longest. The average metamorphosis survival rate of different treatment groups ranged from 72.5% to 90.8%, which was the highest in the control group and the lowest in the rapid desiccation group. Body weight (BW) and body length (BL) of froglets in control and slow desiccation groups were significantly higher than those of moderate or rapid desiccation groups. Body width, ratio of BW to BL, carcass wet weight and the wet weight index of lung and fat body were the lowest in rapid desiccation group. There was no significant difference in the wet weight index of heart, spleen, kidneys and digestive organs, as well as the length index of different segments of whole digestive tract between groups. The maximal response value of froglets to PHA-P appeared at 3 h after injection in different treatments, which was significantly higher in moderate and slow desiccation groups than the control group. There was no significant difference between rapid desiccation group and any other groups. The tadpoles of P. nigromaculatus might accelerate the metamorphosis developmental process to cope with desiccation stress, accompanying with decreased atrophic body size and weakened cell-mediated immunity, which would harm tadpoles to successfully land.

Demineralized bone matrix combined with cytotoxic T-lymphocyte-associated protein 4 promotes osteogenic differentiation of human bone marrow mesenchymal stem cells and suppresses the activation of T lymphocytes in vitro.

Cytotoxic T-lymphocyte-associated protein 4 (CTLA4) can promote osteogenic differentiation of human bone marrow mesenchymal stem cells (hBMMSCs), and CTLA4-modified bone marrow mesenchymal stem cells possess immunoregulatory effects. In the present study, we aimed to construct a new tissue engineering bone using demineralized bone matrix and CTLA4 protein, designated as DBM-CTLA4 (+). The effects of DBM-CTLA4 (+) on the osteogenic differentiation of hBMMSCs and T lymphocyte activation were evaluated through in vitro experiments. The cumulative release of CTLA4 from DBM-CTLA4 (+) was determined using enzyme-linked immunosorbent assay. DBM-CTLA4 (+) was co-cultured in a Transwell chamber with either phytohemagglutinin-treated hBMMSCs or human peripheral blood mononuclear cells (hPBMCs). Osteogenic differentiation of hBMMSCs was assessed by calcium deposition, ALP activity, and the protein levels of COL1A1, RUNX2, BMP2, and OPN. T lymphocyte activity was assessed by measuring the protein levels of IL-2, L-17, HLA-DRA1, IFN-γ, and RANKL. Our results showed that the cumulative release rates of CTLA4 at 7, 14, 21, and 28 days were 12.6% ± 1.4%, 30.2% ± 2.3%, 49.8% ± 3.8%, and 60.5% ± 2.7%, respectively. Compared to the negative control, DBM-CTLA4 (+) promoted the proliferation of hBMMSCs, and enhanced calcium deposition, ALP activity, and protein levels of COL1A1, RUNX2, BMP2, and OPN. Moreover, DBM-CTLA4 (+) decreased the levels of IL-2, IL-17, HLA-DR, IFN-γ, and RANKL in hPBMCs treated with phytohemagglutinin. In conclusion, DBM-CTLA4 (+) promoted proliferation and osteogenic differentiation of hBMMSCs and suppressed T lymphocyte activation.