Cytotoxic Responses and Apoptosis in Rat Kidney Epithelial Cells Exposed to Lead

The toxic effects of lead on normal rat kidney epithelial cells（NRK cells）may occur via various pathways.However,the role of intrinsic mitochondrial pathway in Lead-induced apoptosis in NRK cells has not been investigated.The purpose of our study was to investigate cytotoxic responses and cell apoptosis mediated by lead in NRK cells.

Cytotoxic response of phagocytes in patients newly infected with pulmonary Mycobacterium tuberculosis determined using plasma tumor necrosis factor-alpha,malondialdehyde,and superoxide dismutase:an observational study

Objective: PulmonaryMycobacterium tuberculosis infection can trigger cellular and humoral innate immune responses, which may cause death of the pathogen and or host cells/tissue. We aimed to determine the cytotoxic response of phagocytes in patients with pulmonaryMycobacterium tuberculosis infection based on plasma tumor necrosis factor-alpha (TNF-α), malondialdehyde (MDA), and superoxide dismutase (SOD) levels.Methods: In this observational study, patients newly infected with pulmonaryMycobacterium tuberculosis (n=31;age 37-62 years) and age-matched uninfected volunteers (n=50) were recruited as test and control volunteers, respectively in Owo, Nigeria. The study protocol was reviewed and approved by the Research and Ethics Committee of the Department of Medical Laboratory Science, Achievers University, Owo, Nigeria (AUO/MLS/VII/2009/212). Anti-hepatitis C virus, human immunodeficiency virus antigen/antibody, hepatitis B virus surface antigen, and plasma TNF-α were determined by enzyme-linked immunosorbent assay, SOD, and MDA were determined by colorimetry,Plasmodium by Giemsa thick blood film staining, and acid-fast bacilli in sputum were detected by Ziehl-Neelsen staining.Results: All participants had normal blood glucose levels and tested negative for human immunodeficiency virus antigen/antibody, anti-hepatitis C virus, hepatitis B virus surface antigen, andPlasmodium spp., and had no medical history of cancer. Infected patients had significantly higher plasma MDA and TNF-α levels and significantly lower SOD levels compared with control subjects (allP<0.05).Conclusion: Mycobacterium tuberculosis infection elicited a cytotoxic response by phagocytes, evidenced by significant increases in MDA and TNF-α and a significant decrease in SOD levels.

Dendritic cells engineered to secrete anti-Dc R3 antibody augment cytotoxic T lymphocyte response against pancreatic cancer in vitro

AIM To investigate the enhanced cytotoxic T lymphocyte responses against pancreatic cancer (PC) in vitro induced by dendritic cells (DCs) engineered to secrete anti-DcR3 monoclonal antibody (mAb). METHODS DCs, T lymphocytes and primary PC cells were obtained from PC patients. DCs were transfected with a designed humanized anti-DcR3 monoclonal antibody heavy and light chain mRNA and/or total tumor RNA (DC-tumor-anti-DcR3 RNA or DC-total tumor RNA) by using electroporation technology. The identification, concentration and function of anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA were determined by western blotting and enzyme-linked immunosorbent assay. After co-culturing of autologous isolated PC cells with target DCs, the effects of secreting anti-DcR3 mAb on RNA-DCs' viability and apoptosis were assessed by MTT assay and flow cytometry. Analysis of enhanced antigen-specific immune response against PC induced by anti-DcR3 mAb secreting DCs was performed using a Cr-51 releasing test. T cell responses induced by RNAloaded DCs were analyzed by measuring cytokine levels, including IFN-gamma, IL-10, IL4, TNF-alpha and IL-12. RESULTS The anti-DcR3 mAb secreted by DCs reacted with recombinant human DcR3 protein and generated a band with 35 kDa molecular weight. The secreting mAb was transient, peaking at 24 h and becoming undetectable after 72 h. After co-incubation with DCtumor- anti-DcR3 RNA for designated times, the DcR3 level in the supernatant of autologous PC cells was significantly down-regulated (P < 0.05). DCs secreting anti-DcR3 mAb could improve cell viability and slow down the apoptosis of RNA-loaded DCs, compared with DC-total tumor RNA (P < 0.01). The anti-DcR3 mAb secreted by DC-tumor-anti-DcR3 RNA could enhance the induction of cytotoxic T lymphocytes (CTLs) activity toward RNA-transfected DCs, primary tumor cells, and PC cell lines, compared with CTLs stimulated by DC-total tumor RNA or control group (P < 0.05). Meanwhile, the antigen-specific CTL responses were MHC class I-restricted. The CD4+ T cells and CD8+ T cells incubated with anti-DcR3 mAb secreting DCs could produce extremely higher level IFN-gamma and lower level IL4 than those incubated with DC-total tumor RNA or controls (P < 0.01). CONCLUSION DCs engineered to secrete anti-DcR3 antibody can augment CTL responses against PC in vitro, and the immune-enhancing effects may be partly due to their capability of down-regulating DC apoptosis and adjusting the Th1/Th2 cytokine network.

Adaptive immune response during hepatitis C virus infection

Hepatitis C virus(HCV)infection affects about 170 million people worldwide and it is a major cause of liver cirrhosis and hepatocellular carcinoma.HCV is a hepatotropic non-cytopathic virus able to persist in a great percentage of infected hosts due to its ability to escape from the immune control.Liver damage and disease progression during HCV infection are driven by both viral and host factors.Specifically,adaptive immune response carries out an essential task in controllingnon-cytopathic viruses because of its ability to recognize infected cells and to destroy them by cytopathic mechanisms and to eliminate the virus by non-cytolytic machinery.HCV is able to impair this response by several means such as developing escape mutations in neutralizing antibodies and in T cell receptor viral epitope recognition sites and inducing HCV-specific cytotoxic T cell anergy and deletion.To impair HCV-specific T cell reactivity,HCV affects effector T cell regulation by modulating T helper and Treg response and by impairing the balance between positive and negative co-stimulatory molecules and between pro-and antiapoptotic proteins.In this review,the role of adaptive immune response in controlling HCV infection and the HCV mechanisms to evade this response are reviewed.