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Displaying publications 21 - 27 of 27 in total

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Fulltext Thalidomide as a Potential HIV Latency Reversal Agent: Is It the Right Time to Forget the Ancestral Sins?

Vignesh R, Shankar EM

EBioMedicine, 2017 Oct;24:20-21.
PMID: 28865747 DOI: 10.1016/j.ebiom.2017.08.025
Matched MeSH terms: CD4-Positive T-Lymphocytes/metabolism
Increased level of activated gamma delta lymphocytes correlates with disease severity in HIV infection

Norazmi MN, Arifin H, Jamaruddin MA

Immunol Cell Biol, 1995 Jun;73(3):245-8.
PMID: 7590898

The lymphocyte subset expressing the gamma delta T cell receptor is increased in several infectious diseases including HIV infection. In this study the expression on gamma delta lymphocytes of the T cell activation markers CD25, HLA-DR and CD38, as well as the two isoforms of CD45, namely CD45RA and CD45RO, was determined in the peripheral blood of 56 HIV-infected intravenous drug users and 34 HIV-seronegative blood donors by two-colour flow cytometry. The percentage of gamma delta lymphocytes expressing HLA-DR and CD38 was higher than those in HIV-seronegative controls (P < 0.001 and P < 0.0001, respectively). Furthermore the HLA-DR+gamma delta+ lymphocytes correlated inversely with CD4+ T lymphocyte absolute count (P < 0.02 for both). The levels of gamma delta lymphocytes expressing CD25, CD45RA and CD45RO were similar to those in HIV-seronegative controls. Activated gamma delta lymphocytes may play a role in the HIV disease process and could provide a useful marker for disease progression.

Matched MeSH terms: CD4-Positive T-Lymphocytes/metabolism*
Fulltext Primary oesophageal Ki (CD30)-positive ALK+ anaplastic large cell lymphoma of T-cell phenotype

Yaakup H, Sagap I, Fadilah SA

Singapore Med J, 2008 Oct;49(10):e289-92.
PMID: 18946602

Primary oesophageal lymphoma is a very rare entity, with fewer than 30 reported cases worldwide. It represents an important cause of dysphagia. Most of the oesophageal lymphomas are diffuse large B-cell type, with only one reported case of anaplastic large cell lymphoma (ALCL) of T-cell phenotype. Primary oesophageal lymphomas that are not associated with an immunocompromised state tend to affect elderly patients. We describe the first case of primary oesophageal Ki (CD30)-positive ALK+ALCL of T-cell phenotype in a 34-year-old immunocompetent woman, who presented with a two-year history of dysphagia. She was treated with chemotherapy and endoscopic oesophageal dilations and stenting, resulting in complete remission of the lymphoma and resolution of the dysphagia. She then underwent autologous peripheral blood haematopoietic stem cell transplantation and remained disease-free two years after the diagnosis.

Matched MeSH terms: T-Lymphocytes/metabolism
Fulltext Immunosuppressive effects of the standardized extract of Phyllanthus amarus on cellular immune responses in Wistar-Kyoto rats

Ilangkovan M, Jantan I, Mesaik MA, Bukhari SN

Drug Des Devel Ther, 2015;9:4917-30.
PMID: 26347462 DOI: 10.2147/DDDT.S88189

Phyllanthus amarus (family: Euphorbiaceae) is of immense interest due to its wide spectrum of biological activities. In the present study, the standardized 80% ethanol extract of P. amarus was investigated for its modulatory activity on various cellular immune parameters, including chemotaxis of neutrophils, engulfment of Escherichia coli by neutrophils, and Mac-1 expression, in leukocytes isolated from treated/nontreated Wistar-Kyoto rats. The detailed cell-mediated activity of P. amarus was also investigated, including analysis of the effects on T- and B-cell proliferation and CD4(+) and CD8(+) T-cell subsets in splenic mononuclear cells, and estimation of serum cytokine production by activated T-cells. The main components of the extract, phyllanthin, hypophyllanthin, corilagin, geraniin, ellagic acid, and gallic acid were identified and quantitatively analyzed in the extracts, using validated reversed-phase high-performance liquid chromatography (HPLC) methods. N-formyl-methionyl-leucyl-phenylalanine (fMLP)-induced neutrophils isolated from rats administered with the extract of P. amarus, at doses ranging from 100 to 400 mg/kg for 14 days, revealed a significant dose-dependent reduction in neutrophil migration (P<0.05). Similar patterns of inhibition were also observed in phagocytic activity and in fMLP-induced changes in expression of β2 integrin polymorphonuclear neutrophils. The results in P. amarus-treated rats also demonstrated a dose-dependent inhibition of both lipopolysaccharide-stimulated B-cell proliferation and concanavalin A-stimulated T-cell proliferation as compared with sensitized control. At a dose of 400 mg/kg (P<0.01), there was a significant decrease in the (%) expression of CD4(+) and CD8(+) in splenocytes and in serum cytokines of T helper (Th1) (IL-2 and IFN-γ) and Th2 (IL-4). In conclusion, P. amarus showed effective immunosuppressive activities in cellular immune response, by various immune regulatory mechanisms, and may be useful for improvement of immune-related disorders.

Matched MeSH terms: T-Lymphocytes/metabolism
Fulltext Attrition of TCR Vα7.2+ CD161++ MAIT cells in HIV-tuberculosis co-infection is associated with elevated levels of PD-1 expression

Saeidi A, Tien Tien VL, Al-Batran R, Al-Darraji HA, Tan HY, Yong YK, et al.

PLoS One, 2015;10(4):e0124659.
PMID: 25894562 DOI: 10.1371/journal.pone.0124659

Mucosal-associated invariant T (MAIT) cells are evolutionarily conserved antimicrobial MR1-restricted CD8(+) T cells co-expressing the semi-invariant TCR Vα7.2, and are numerous in the blood and mucosal tissues of humans. MAIT cells appear to undergo exhaustion in chronic viral infections. However, their role in human immunodeficiency virus type 1 (HIV-1) mono-infection and HIV/tuberculosis (TB) co-infection have seldom been elaborately investigated. We conducted a cross-sectional study to investigate the frequencies and phenotypes of CD161(++)CD8(+) T cells among anti-retroviral therapy (ART)/anti-TB therapy (ATT) treatment-naïve HIV/TB co-infected, ART/TB treated HIV/TB co-infected, ART naïve HIV-infected, ART-treated HIV-infected patients, and HIV negative healthy controls (HCs) by flow cytometry. Our data revealed that the frequency of MAIT cells was severely depleted in HIV mono- and HIV/TB co-infections. Further, PD-1 expression on MAIT cells was significantly increased in HIV mono- and HIV-TB co-infected patients. The frequency of MAIT cells did not show any significant increase despite the initiation of ART and/or ATT. Majority of the MAIT cells in HCs showed a significant increase in CCR6 expression as compared to HIV/TB co-infections. No marked difference was seen with expressions of chemokine co-receptor CCR5 and CD103 among the study groups. Decrease of CCR6 expression appears to explain why HIV-infected patients display weakened mucosal immune responses.

Matched MeSH terms: CD8-Positive T-Lymphocytes/metabolism
Fulltext Therapeutic challenges and current immunomodulatory strategies in targeting the immunosuppressive pancreatic tumor microenvironment

Looi CK, Chung FF, Leong CO, Wong SF, Rosli R, Mai CW

J Exp Clin Cancer Res, 2019 Apr 15;38(1):162.
PMID: 30987642 DOI: 10.1186/s13046-019-1153-8

BACKGROUND: Pancreatic cancer is one of the most lethal type of cancers, with an overall five-year survival rate of less than 5%. It is usually diagnosed at an advanced stage with limited therapeutic options. To date, no effective treatment options have demonstrated long-term benefits in advanced pancreatic cancer patients. Compared with other cancers, pancreatic cancer exhibits remarkable resistance to conventional therapy and possesses a highly immunosuppressive tumor microenvironment (TME).
MAIN BODY: In this review, we summarized the evidence and unique properties of TME in pancreatic cancer that may contribute to its resistance towards immunotherapies as well as strategies to overcome those barriers. We reviewed the current strategies and future perspectives of combination therapies that (1) promote T cell priming through tumor associated antigen presentation; (2) inhibit tumor immunosuppressive environment; and (3) break-down the desmoplastic barrier which improves tumor infiltrating lymphocytes entry into the TME.
CONCLUSIONS: It is imperative for clinicians and scientists to understand tumor immunology, identify novel biomarkers, and optimize the position of immunotherapy in therapeutic sequence, in order to improve pancreatic cancer clinical trial outcomes. Our collaborative efforts in targeting pancreatic TME will be the mainstay of achieving better clinical prognosis among pancreatic cancer patients. Ultimately, pancreatic cancer will be a treatable medical condition instead of a death sentence for a patient.

Matched MeSH terms: T-Lymphocytes/metabolism
The aminopeptidase inhibitor, z-L-CMK, is toxic and induces cell death in Jurkat T cells through oxidative stress

Yeo EH, Goh WL, Chow SC

Toxicol. Mech. Methods, 2018 Mar;28(3):157-166.
PMID: 28849708 DOI: 10.1080/15376516.2017.1373882

The leucine aminopeptidase inhibitor, benzyloxycarbonyl-leucine-chloromethylketone (z-L-CMK), was found to be toxic and readily induce cell death in Jurkat T cells. Dose-response studies show that lower concentration of z-L-CMK induced apoptosis in Jurkat T cells whereas higher concentration causes necrosis. In z-L-CMK-induced apoptosis, both the initiator caspases (-8 and -9) and effector caspases (-3 and -6) were processed to their respective subunits. However, the caspases remained intact in z-L-CMK-induced necrosis. The caspase inhibitor, z-VAD-FMK inhibited z-L-CMK-mediated apoptosis and caspase processing but has no effect on z-L-CMK-induced necrosis in Jurkat T cells. The high mobility group protein B1 (HMGB1) protein was found to be released into the culture medium by the necrotic cells and not the apoptotic cells. These results indicate that the necrotic cell death mediated by z-L-CMK at high concentrations is via classical necrosis rather than secondary necrosis. We also demonstrated that cell death mediated by z-L-CMK was associated with oxidative stress via the depletion of intracellular glutathione (GSH) and increase in reactive oxygen species (ROS), which was blocked by N-acetyl cysteine. Taken together, the results demonstrated that z-L-CMK is toxic to Jurkat T cells and induces apoptosis at low concentrations, while at higher concentrations the cells die of necrosis. The toxic side effects in Jurkat T cells mediated by z-L-CMK are associated with oxidative stress via the depletion of GSH and accumulation of ROS.

Matched MeSH terms: T-Lymphocytes/metabolism