CTLA-4 was first identified in 1991 as a second receptor for the T cell costimulation ligand B7. Uncertainties about its biological function plagued the early years after its discovery until 1995, when it was confirmed to be an inhibitor of T cell responses. CTLA-4 has since scored in the clinic as a target for antitumor therapy and as a soluble inhibitor of autoimmunity.

Cytotoxic T lymphocyte antigen-4 (CTLA-4/CD152) is a member of the CD28 family of T cell effector antigens. Current belief, based primarily on results from gene-deleted mice, is that CTLA-4 promotes suppression of T cell proliferation. In this manuscript, Mark Slifka and colleagues compare antiviral responses of unmanipulated virus-specific CTLA-4 and CTLA-4 T cells. The results of this work su...

The CTLA-4 pathway is a key regulator of T cell activation and a critical failsafe against autoimmunity. Although early models postulated that CTLA-4 transduced a negative signal, in vivo evidence suggests that CTLA-4 functions in a cell-extrinsic manner. That multiple cell-intrinsic mechanisms have been attributed to CTLA-4, yet its function in vivo appears to be cell-extrinsic, has been an on...

Submit Manuscript | http://medcraveonline.com Abbreviations: AIDS: Acquired Immunodeficiency Syndrome; B-cell: B lymphocyte; CTL: Cytotoxic T-lymphocyte; ELISA: Enzyme-linked Immunosorbent Assay; Env: Envelope; ER: Endoplasmic Reticulum; HIV: Human Immunodeficiency Virus; MHC: Major Histocompatibility Complex; NMR: Nuclear Magnetic Resonance; TAP: Transporter Associated with Antigen Processing;...

The recent cloning and identification of a variety of regulatory and counter-regulatory molecules on T cells and antigen presenting cells has led to the development of antibodies and other molecules that either stimulate or abrogate these immune functions. Patients with autoimmune disease, graft rejection and cancer might benefit from the ability to manipulate immune regulatory pathways. The fi...

backgrounds: seminoma is frequently observed in human and canine testes especially in cryptorchids. canine and human seminomas are typically associated with leukocytic infiltration. objectives: we aimed to identify the type of lymphocytes that infiltrate to seminomas. methods: tumor infiltrating lymphocytes were evaluated by immunohistological techniques in 5 dogs with diffuse seminoma. routine...

We examine simple mathematical models to investigate the circumstances under which the dynamics of cytotoxic T-lymphocyte (CTL) activation and differentiation may result in the loss of virus specific CD8+ cells, a process known as CTL exhaustion. We distinguish between two general classes of viruses: (i) viruses infecting cells that are not involved in the immune response; and (ii) viruses infe...

Qa-2 is a nonclassical class I molecule encoded by the Q7 gene within the mouse major histocompatibility complex (MHC). Results from previous experiments on Qa-2, and on a chimeric Ld molecule (LQ3) in which the alpha 3 domain is encoded by Q7b, suggested that the alpha 3 domain of Qa-2 does not carry out the functions typical of the alpha 3 domains in other classical and nonclassical class I a...