CTLA-4 is known as a central inhibitor of T cell responses. It terminates T cell activation and proliferation and induces resistance against activation induced cell death. However, its impact on memory formation of adaptive immune responses is still unknown. In this study, we demonstrate that although anti-CTLA-4 mAb treatment during primary immunization of mice initially enhances the number of...

Cytolytic killing is a major effector mechanism in the elimination of virally infected and tumor cells. The innate cytolytic effectors, natural killer (NK) cells, and the adaptive effectors, cytotoxic T cells (CTL), despite differential immune recognition, both use the same lytic mechanism, cytolytic granule release. Using live cell video fluorescence microscopy in various primary cell models o...

NKT cells perform crucial roles in tumor surveillance, functioning as regulators of early host response. In this study, we have assessed the effects of NKT activation at the time of tumor Ag immunization, and have evaluated the contributions of CD4+ and CD8+ T cells in tumor rejection during adaptive immune response against live tumor cells. Our data indicate that CD4+ T cells play critical rol...

A large number of CD4+ T cell clones, obtained from peripheral blood T lymphocytes by direct limiting dilution, allowed us to address the question whether functional heterogeneity exists within the human CD4+ T cell subset. Cytotoxic capacity of cloned T cells was analyzed with the use of anti-CD3 antibodies and target cells bearing FcR for murine IgG. 6 of 12 CD4+ clones obtained were able to ...

background: mentha species are widely used in traditional medicine mostly as anti-flatulence. nowadays, their usage as flavor and preservative in food, cosmetic and pharmaceutical industries has been developed. moreover, cytotoxic effects of some mentha species have been reported. objective: in this study, cytotoxic properties of mentha piperita, m. spicata, m. aquatica, m. crispa, m. pulegium ...

background and objectives: iran owns a rich and prestigious heritage of medicinal herbs but the majority of these plants have not yet undergone chemical, pharmacological and toxicological studies. in the present study some species form northern parts of iran were evaluated for cytotoxicity. methods: sixteen medicinal plants were extracted with methanol and screened for their cytotoxic activitie...

The cytotoxic T cell response to Epstein-Barr virus as measured by the regression assay was found to be impaired in a group of patients with active rheumatoid arthritis (RA). When these patients responded clinically to treatment with sulphasalazine there was a concomitant increase in the strength of this virus specific T cell response. The suggestion of a correlation between disease activity an...

Fresh human T lymphocytes respond proliferatively to soluble antigens, such as PPD, provided the cell donor has been immunized to those antigens in vivo. This proliferative response requires the addition of antigen-presenting cells bearing autologous HLA-D antigens. This report demonstrates that the proliferative response to PPD activates a collaborative response that aids in the activation of ...

Host defenses are profoundly compromised in HIV-infected hosts due to progressive depletion of CD4+ T lymphocytes. A hallmark of HIV infection is Pneumocystis carinii (PC) pneumonia. Recently, CD8+ T cells, which are recruited to the lung in large numbers in response to PC infection, have been associated with some level of host defense as well as contributing to lung injury in BALB/c mice. In t...

Patient-derived tumor organoids (PDTOs) hold great promise for preclinical and translational research predicting the patient therapy response from ex vivo drug screenings. However, current adenosine triphosphate (ATP)-based screening assays do not capture complexity of a (cytostatic or cytotoxic) intratumor heterogeneity that has been shown to be retained in PDTOs due bulk readout. Live-cell im...