CD4⁺CD25⁻ T Cells Transduced to Express MHC Class I-Restricted Epitope-Specific TCR Synthesize Th1 Cytokines and Exhibit MHC Class I-Restricted Cytolytic Effector Function in a Human Melanoma Model

Cytolytic T cell-centric active specific and adoptive immunotherapeutic approaches might benefit from the simultaneous engagement of CD4⁺ T cells. Considering the difficulties in simultaneously engagingCD4⁺ and CD8⁺ T cells in tumor immunotherapy, especially in an Ag-specific manner, redirecting CD4⁺ T cells to MHC class I-restricted epitopes through engineered expression of MHC class I-restricted epitope-specific TCRs in CD4⁺ T cells has emerged as a strategic consideration. Such TCR-engineered CD4⁺ T cells have been shown to be capable of synthesizing cytokines as well as lysing target cells. We have conducted a critical examination of functional characteristics of CD4⁺ T cells engineered to express the α- and β-chains of a high functional avidity TCR specific for the melanoma epitope, MART-1, as a prototypic human tumor Ag system. We found that unpolarized CD4⁺CD25⁻ T cells engineered to express the MART-1 TCR selectively synthesize Th1 cytokines and exhibit a potent Ag-specific lytic granule exocytosis-mediated cytolytic effector function of comparable efficacy to that of CD8⁺ CTL. Such TCR engineered CD4⁺ T cells, therefore, might be useful in clinical immunotherapy

T Cells Expanded in Presence of IL-15 Exhibit Increased Antioxidant Capacity And Innate Effector Molecules

Persistence of effector cytotoxic T lymphocytes (CTLs) during an immunological response is critical for successfully controlling a viral infection or tumor growth. Various cytokines are known to play an important part in regulating the immune response. The IL-2 family of cytokines that includes IL-2 and IL-15 are known to function as growth and survival factors for antigen-experienced T cells. IL-2 and IL-15 possess similar properties, including the ability to induce T cell proliferation. Whereas long term IL-2 exposure has been shown to promote apoptosis and limit CD8+ memory T cell survival and proliferation, it is widely believed that IL-15 can inhibit apoptosis and helps maintain a memory CD8+ T-cell population. However, mechanisms for superior outcomes for IL-15 as compared to IL-2 are still under investigation. Our data shows that human T cells cultured in the presence of IL-15 exhibit increased expression of anti-oxidant molecules Glutathione reductase (GSR), Thioredoxin reductase 1 (TXNDR1), Peroxiredoxin (PRDX), Superoxide dismutase (SOD). An increased expression of cell-surface thiols, intracellular glutathione, and thioredoxins was also noted in IL-15 cultured T cells. Additionally, IL-15 cultured T cells also showed an increase in cytolytic effector molecules. Apart from increased level of Granzyme A and Granzyme B, IL-15 cultured T cells exhibit increased accumulation of reactive oxygen (ROS) and reactive nitrogen (RNS) species as compared to IL-2 cultured T cells. Overall, this study suggests that T cells cultured in IL-15 show increase persistence not only due to increased anti-apoptotic proteins but also due to increased anti-oxidant levels, which is further complimented by increased cytolytic effector functions

Medical Education: The Hot Seat

Medical science has eventually metamorphosed from ′Knowledge based′ to ′Skill based′ applied social science. So, the age-old traditional courses and curriculums in Indian medical education need a overhauling with radical modifications. With a paradigm shift, we have to take into account not only the help of scientific feedback from the teachers and students but also from all the stakeholders of health care delivery system