Displaying publications 41 - 53 of 53 in total

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  1. Fulltext Enrichment of gut-derived Fusobacterium is associated with suboptimal immune recovery in HIV-infected individuals
    Lee SC, Chua LL, Yap SH, Khang TF, Leng CY, Raja Azwa RI, et al.
    Sci Rep, 2018 09 24;8(1):14277.
    PMID: 30250162 DOI: 10.1038/s41598-018-32585-x
    We explored the gut microbiota profile among HIV-infected individuals with diverse immune recovery profiles following long-term suppressive ART and investigated the relationship between the altered bacteria with markers of immune dysfunction. The microbiota profile of rectal swabs from 26 HIV-infected individuals and 20 HIV-uninfected controls were examined. Patients were classified as suboptimal responders, sIR (n = 10, CD4 T-cell <350 cells/ul) and optimal responders, oIR (n = 16, CD4 T-cell >500 cells/ul) after a minimum of 2 years on suppressive ART. Canonical correlation analysis(CCA) and multiple regression modelling were used to explore the association between fecal bacterial taxa abundance and immunological profiles in optimal and suboptimal responders. We found Fusobacterium was significantly enriched among the HIV-infected and the sIR group. CCA results showed that Fusobacterium abundance was negatively correlated with CD4 T-cell counts, but positively correlated with CD4 T-cell activation and CD4 Tregs. Multiple linear regression analysis adjusted for age, baseline CD4 T-cell count, antibiotic exposure and MSM status indicated that higher Fusobacterium relative abundance was independently associated with poorer CD4 T-cell recovery following ART. Enrichment of Fusobacterium was associated with reduced immune recovery and persistent immune dysfunction following ART. Modulating the abundance of this bacterial taxa in the gut may be a viable intervention to improve immune reconstitution in our setting.
    Matched MeSH terms: Lymphocyte Activation/immunology
  2. Immunomodulatory activity of polyphenols derived from Cassia auriculata flowers in aged rats
    John CM, Sandrasaigaran P, Tong CK, Adam A, Ramasamy R
    Cell Immunol, 2011;271(2):474-9.
    PMID: 21924708 DOI: 10.1016/j.cellimm.2011.08.017
    The immunomodulatory activity of Cassia auriculata (CA)-derived polyphenols was tested on aged rats. Rats (24-26 months old) were given CA polyphenols supplementation at doses of 25, 50, and 100 mg/kg for 28 days. Flow cytometry analysis of CA polyphenols-treated aged rats showed increased T and B cells percentage along with enhanced proliferation of splenocytes in both resting and LPS-stimulated cells. Increased percentage of pan T cells is further supported by an elevation of CD4+, CD8+, and CD4+CD25+ regulatory cells. In terms of innate immune cell activity, CA polyphenol supplementation reduced the oxidative burst activity of neutrophils in response to PMA and Escherichia coli activation. Our results collectively show that polyphenols derived from CA boost T cell immunity by increasing the number of T cells and its sensitivity towards stimulants and decreasing ROS production by neutrophils that could potentially harm multiple biological systems in aged individuals.
    Matched MeSH terms: Lymphocyte Activation/drug effects
  3. Fulltext Human mesenchymal stem cells inhibit the differentiation and effector functions of monocytes
    Maqbool M, Algraittee SJR, Boroojerdi MH, Sarmadi VH, John CM, Vidyadaran S, et al.
    Innate Immun, 2020 07;26(5):424-434.
    PMID: 32635840 DOI: 10.1177/1753425919899132
    Although monocytes represent an essential part of the host defence system, their accumulation and prolonged stimulation could be detrimental and may aggravate chronic inflammatory diseases. The present study has explored the less-understood immunomodulatory effects of mesenchymal stem cells on monocyte functions. Isolated purified human monocytes were co-cultured with human umbilical cord-derived mesenchymal stem cells under appropriate culture conditions to assess monocytes' vital functions. Based on the surface marker analysis, mesenchymal stem cells halted monocyte differentiation into dendritic cells and macrophages and reduced their phagocytosis functions, which rendered an inability to stimulate T-cell proliferation. The present study confers that mesenchymal stem cells exerted potent immunosuppressive activity on monocyte functions such as differentiation, phagocytosis and Ag presentation; hence, they promise a potential therapeutic role in down-regulating the unwanted monocyte-mediated immune responses in the context of chronic inflammatory diseases.
    Matched MeSH terms: Lymphocyte Activation
  4. Human mesenchymal stromal cells modulate T-cell immune response via transcriptomic regulation
    Vellasamy S, Tong CK, Azhar NA, Kodiappan R, Chan SC, Veerakumarasivam A, et al.
    Cytotherapy, 2016 10;18(10):1270-83.
    PMID: 27543068 DOI: 10.1016/j.jcyt.2016.06.017
    BACKGROUND AIMS: Mesenchymal stromal cells (MSCs) have been identified as pan-immunosuppressant in various in vitro and in vivo inflammatory models. Although the immunosuppressive activity of MSCs has been explored in various contexts, the precise molecular signaling pathways that govern inhibitory functions remain poorly elucidated.

    METHODS: By using a microarray-based global gene expression profiling system, this study aimed to decipher the underlying molecular pathways that may mediate the immunosuppressive activity of umbilical cord-derived MSCs (UC-MSCs) on activated T cells.

    RESULTS: In the presence of UC-MSCs, the proliferation of activated T cells was suppressed in a dose-depended manner by cell-to-cell contact mode via an active cell-cycle arrest at the G0/G1 phase of the cell cycle. The microarray analysis revealed that particularly, IFNG, CXCL9, IL2, IL2RA and CCND3 genes were down-regulated, whereas IL11, VSIG4, GFA1, TIMP3 and BBC3 genes were up-regulated by UC-MSCs. The dysregulated gene clusters associated with immune-response-related ontologies, namely, lymphocyte proliferation or activation, apoptosis and cell cycle, were further analyzed.

    CONCLUSIONS: Among the nine canonical pathways identified, three pathways (namely T-helper cell differentiation, cyclins and cell cycle regulation, and gap/tight junction signalling pathways) were highly enriched with these dysregulated genes. The pathways represent putative molecular pathways through which UC-MSCs elicit immunosuppressive activity toward activated T cells. This study provides a global snapshot of gene networks and pathways that contribute to the ability of UC-MSCs to suppress activated T cells.

    Matched MeSH terms: Lymphocyte Activation/genetics*
  5. Fulltext A case of chronic myeloid leukaemia in blast transformation with leukemic ascites
    Mohd Ridzuan MS, Yap E, Wan Fariza WJ, Fadilah SA, Salwati S
    Med J Malaysia, 2016 04;71(2):85-7.
    PMID: 27326952 MyJurnal
    Chronic Myeloid Leukaemia (CML) is a disease characterised by a distinctive marker that is the Philadelphia Chromosome and an ability to transform into blast phase, which confers a poor prognosis. The median survival was reported to be between three to six months in correlation to blast phase. Extramedullary involvement with CML to sites such as pleural, meningeal and bones have been reported. We report a case of 41-year-old man who was diagnosed with CML in blast phase and presented with ascites. Ultrasound of abdomen showed coarse echotexture of liver suggestive leukaemic infiltration to the liver. The liver profile was severely deranged and associated with coagulopathy. Flow cytometry analysis of the peritoneal fluid revealed presence of myeloblasts consistent with CML in blast crisis with leukaemic ascites. Bone marrow biopsy also confirmed disease transformation. He received standard induction chemotherapy for acute myeloid leukaemia with dose modifications based on liver enzymes performance. Our case highlights an unusual presentation of CML in blast crisis with leukaemic ascites and the challenges in managing cytotoxic treatments due to the liver infiltration.
    Matched MeSH terms: Lymphocyte Activation*
  6. The artificial loss of Runx1 reduces the expression of quiescence-associated transcription factors in CD4(+) T lymphocytes
    Wong WF, Kohu K, Nagashima T, Funayama R, Matsumoto M, Movahed E, et al.
    Mol Immunol, 2015 Dec;68(2 Pt A):223-33.
    PMID: 26350416 DOI: 10.1016/j.molimm.2015.08.012
    The Runx1 transcription factor cooperates with or antagonizes other transcription factors and plays essential roles in the differentiation and function of T lymphocytes. Previous works showed that Runx1 is expressed in peripheral CD4(+) T cells which level declines after T cell receptor (TCR) activation, and artificial deletion of Runx1 causes autoimmune lung disease in mice. The present study addresses the mechanisms by which Runx1 contributes to the maintenance of peripheral CD4(+) T cell quiescence. Microarray and quantitative RT-PCR analyses were employed to compare the transcriptome of Runx1 -/- CD4(+) T cells to those of unstimulated and TCR-stimulated Runx1 +/- cells. The results identified genes whose expression was modulated similarly by Runx1 deletion and TCR activation. Among them, genes encoding cytokines, chemokines, and Jak/STAT signaling molecules were substantially induced. In Runx1-deleted T cells, simultaneous increases in Il-17A and Rorγc, a known master gene in TH17 differentiation, were observed. In addition, we observed that the loss of Runx1 reduced the transcription of genes encoding quiescence-associated transcription factors, including Foxp1, Foxo1, and Klf2. Interestingly, we identified consensus Runx1 binding sites at the promoter regions of Foxp1, Foxo1, and Klf2 genes, which can be enriched by chromatin immunoprecipitation assay with an anti-Runx1 antibody. Therefore, we suggest that Runx1 may activate, directly or indirectly, the expression of quiescence-associated molecules and thereby contribute to the maintenance of quiescence in CD4(+) T cells.
    Matched MeSH terms: Lymphocyte Activation
  7. Concurrent loss of co-stimulatory molecules and functional cytokine secretion attributes leads to proliferative senescence of CD8(+) T cells in HIV/TB co-infection
    Saeidi A, Chong YK, Yong YK, Tan HY, Barathan M, Rajarajeswaran J, et al.
    Cell Immunol, 2015 Sep;297(1):19-32.
    PMID: 26071876 DOI: 10.1016/j.cellimm.2015.05.005
    The role of T-cell immunosenescence and functional CD8(+) T-cell responses in HIV/TB co-infection is unclear. We examined and correlated surrogate markers of HIV disease progression with immune activation, immunosenescence and differentiation using T-cell pools of HIV/TB co-infected, HIV-infected and healthy controls. Our investigations showed increased plasma viremia and reduced CD4/CD8 T-cell ratio in HIV/TB co-infected subjects relative to HIV-infected, and also a closer association with changes in the expression of CD38, a cyclic ADP ribose hydrolase and CD57, which were consistently expressed on late-senescent CD8(+) T cells. Up-regulation of CD57 and CD38 were directly proportional to lack of co-stimulatory markers on CD8(+) T cells, besides diminished expression of CD127 (IL-7Rα) on CD57(+)CD4(+) T cells. Notably, intracellular IFN-γ, perforin and granzyme B levels in HIV-specific CD8(+) T cells of HIV/TB co-infected subjects were diminished. Intracellular CD57 levels in HIV gag p24-specific CD8(+) T cells were significantly increased in HIV/TB co-infection. We suggest that HIV-TB co-infection contributes to senescence associated with chronic immune activation, which could be due to functional insufficiency of CD8(+) T cells.
    Matched MeSH terms: Lymphocyte Activation/immunology
  8. Decrease of CD69 levels on TCR Vα7.2+CD4+ innate-like lymphocytes is associated with impaired cytotoxic functions in chronic hepatitis B virus-infected patients
    Yong YK, Tan HY, Saeidi A, Rosmawati M, Atiya N, Ansari AW, et al.
    Innate Immun, 2017 07;23(5):459-467.
    PMID: 28606013 DOI: 10.1177/1753425917714854
    Hepatitis B virus (HBV) infection is a major cause of chronic liver disease that may progress to liver cirrhosis and hepatocellular carcinoma. Host immune responses represent the key determinants of HBV clearance or persistence. Here, we investigated the role of the early activation marker, CD69 and effector cytokines, granzyme B (GrB) and IFN-γ in the exhaustion of innate-like TCR Vα7.2+CD4+T cells, in 15 individuals with chronic HBV (CHB) infection where six were HBV DNA+ and nine were HBV DNA-. The percentage of cytokine-producing T cells and MAIT cells were significantly perturbed in HBV patients relative to healthy controls (HCs). The intracellular expression of GrB and IFN-γ was significantly reduced in MAIT cells derived from HBV-infected patients as compared to HCs, and the levels correlated with the percentage and levels [mean fluorescence intensity (MFI)] of CD69 expression. The total expression of CD69 (iMFI) was lower in CHB patients as compared to HCs. The frequency of CD69+ cells correlated with the levels of cytokine expression (MFI), particularly in CHB patients as compared to HCs. In summary, the polyfunctionality of peripheral T cells was significantly reduced among CHB patients, especially in the TCR Vα7.2+CD4+T cells, and the levels of cytokine expression correlated with functional cytokine levels.
    Matched MeSH terms: Lymphocyte Activation
  9. Increased frequency of late-senescent T cells lacking CD127 in chronic hepatitis C disease
    Barathan M, Mohamed R, Saeidi A, Vadivelu J, Chang LY, Gopal K, et al.
    Eur J Clin Invest, 2015 May;45(5):466-74.
    PMID: 25721991 DOI: 10.1111/eci.12429
    Hepatitis C virus (HCV) causes persistent disease in ~85% of infected individuals, where the viral replication appears to be tightly controlled by HCV-specific CD8+ T cells. Accumulation of senescent T cells during infection results in considerable loss of functional HCV-specific immune responses.
    Matched MeSH terms: Lymphocyte Activation/immunology
  10. Gender effect on in vitro lymphocyte subset levels of healthy individuals
    Abdullah M, Chai PS, Chong MY, Tohit ER, Ramasamy R, Pei CP, et al.
    Cell Immunol, 2012;272(2):214-9.
    PMID: 22078320 DOI: 10.1016/j.cellimm.2011.10.009
    Differences in gender immune response have resulted in differences in immune protection and susceptibility to inflammatory diseases. Cultured peripheral blood mononuclear cells (PBMC) are widely used in immunomodulation studies, yet the influence of gender is usually not considered. We examined the effect of in vitro culture and phytohaemagglutinin (PHA) stimulation on PBMC lymphocyte subsets using flowcytometry. Full blood counts of whole blood showed higher levels of lymphocyte in male subjects. Lymphocyte subsets enumeration revealed higher NK cell counts in males and higher B cells in females. Cultured PBMC resulted in significant increases in B and total T cell percentages among females and NK cells among males. PHA stimulated significantly increased percentages of NK and total T cells in males and total activated T cells (CD69+) in females. Our results showed significant gender differences in lymphocyte subsets in cultured conditions. This may affect experimental outcome.
    Matched MeSH terms: Lymphocyte Activation/immunology
  11. Fulltext Long term Tai Chi exercise reduced DNA damage and increased lymphocyte apoptosis and proliferation in older adults
    Goon JA, Noor Aini AH, Musalmah M, Yasmin Anum MY, Wan Ngah WZ
    Med J Malaysia, 2008 Oct;63(4):319-24.
    PMID: 19385493 MyJurnal
    Effect of Tai Chi exercise on the level of DNA damage using the comet assay, lymphocyte viability and frequency of sister chromatid exchange (SCE) were determined in adults aged above 45. Tai Chi participants of 7 years (n=35), showed higher level of normal DNA and lower level of mild and severely damaged DNA as compared to the sedentary subjects (n=35). The former are suggested to have effective DNA repair mechanism as their frequency of SCE was markedly lower. Higher lymphocyte apoptosis and proliferation found in the Tai Chi participants also indicated that the exercise promotes renewal and regeneration of lymphocytes.
    Matched MeSH terms: Lymphocyte Activation*
  12. TRPM4 expression is associated with activated B cell subtype and poor survival in diffuse large B cell lymphoma
    Loo SK, Ch'ng ES, Md Salleh MS, Banham AH, Pedersen LM, Møller MB, et al.
    Histopathology, 2017 Jul;71(1):98-111.
    PMID: 28248435 DOI: 10.1111/his.13204
    AIMS: Transient receptor potential channel melastatin 4 (TRPM4) is an ion channel that regulates influx of calcium cations (Ca2+ ). Recent studies suggest that TRPM4 is an oncoprotein, and its up-regulated transcript level has been reported in diffuse large B cell lymphoma (DLBCL). We aimed to investigate TRPM4 protein expression pattern in non-malignant tissues and DLBCL cases, and its association with clinico-demographic parameters and survival in DLBCL.

    METHODS AND RESULTS: Analysis of publicly available DLBCL microarray data sets showed that TRPM4 transcripts were up-regulated in DLBCL compared to normal germinal centre B (GCB) cells, were expressed more highly in the activated B cell-like DLBCL (ABC-DLBCL) subtype and higher TRPM4 transcripts conferred worse overall survival (OS) in R-CHOP (rituximab, cyclophosphamide, doxorubicin, vincristine and prednisone)-treated DLBCL cases (P < 0.05). Our immunohistochemical analysis showed that TRPM4 was expressed in various human tissues but not in normal B cells within lymphoid tissues (reactive tonsil, lymph node and appendix). TRPM4 protein was present in 26% (n = 49 of 189) of our cohort of R-CHOP-treated DLBCL cases and this was associated significantly with more aggressive clinical parameters, including higher lactate dehydrogenase (LDH), Eastern Cooperative Oncology Group (ECOG) scores or stage (P < 0.01 for each of the parameters) and the ABC-DLBCL subtype (P = 0.016). TRPM4 positivity conferred significantly worse OS (P = 0.004) and progression-free survival (PFS) (P = 0.005). Worse OS remained associated significantly with TRPM4 positivity in multivariate analysis, including higher International Prognostic Index (IPI) or the non-GCB DLBCL phenotype (P < 0.05).

    CONCLUSIONS: TRPM4 protein expression is up-regulated in DLBCL cases compared to non-malignant B cells with preferential expression in ABC-DLBCL cases, and it confers significantly poorer DLBCL patient outcomes.

    Matched MeSH terms: Lymphocyte Activation/immunology
  13. Fulltext The modulation of PPARγ1 and PPARγ2 mRNA expression by ciglitazone in CD3/CD28-activated naïve and memory CD4+ T cells
    Norazmi MN, Mohamed R, Nurul AA, Yaacob NS
    Clin. Dev. Immunol., 2012;2012:849195.
    PMID: 22548115 DOI: 10.1155/2012/849195
    Given their roles in immune regulation, the expression of the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) 1 and 2 isoforms was investigated in human naïve (CD45RA+) and memory (CD45RO+) CD4+ T cells. Stimulation of both types of cells via the CD3/CD28 pathway resulted in high expression of both PPARγ receptors as measured by real-time PCR. Treatment with the PPARγ agonist, ciglitazone, increased PPARγ1 expression but decreased PPARγ2 expression in stimulated naïve and memory cells. Furthermore, when present, the magnitude of both PPARγ receptors expression was lower in naïve cells, perhaps suggesting a lower regulatory control of these cells. Similar profiles of selected proinflammatory cytokines were expressed by the two cell types following stimulation. The induction of PPARγ1 and suppression of PPARγ2 expressions in naïve and memory CD4+ T cells in the presence of ciglitazone suggest that the PPARγ subtypes may have different roles in the regulation of T-cell function.
    Matched MeSH terms: Lymphocyte Activation/drug effects; Lymphocyte Activation/immunology
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