Controlling Mature CD4⁺ T Cell Responses

Abstract

Immune responses are by necessity highly regulated to achieve the appropriate balance of aggression and restraint. Among the many factors involved in maintaining this balance are the interactions between accessory molecule receptors expressed on T cells and their ligands on antigen-presenting cells. Our studies during the past several years have focused on defining how particular accessory molecule interactions influence the activation of naïve CD4+ T cells and the subsequent development of effector function. In this article, we discuss our findings on the effects of distinct accessory molecules with particular attention to the unique roles of LFA-1 and CD28 during different phases of the naïve CD4+ cell response.

T cell receptor excision circles (TRECs), CD4+, CD8+ and their CD45RO+ and CD45RA+ subpopulations in hepatitis C virus (HCV)-HIV-co-infected patients during treatment with interferon alpha plus ribavirin: analysis in a population on effective antiretroviral therapy

“…CD45RA is detected on the cell membrane after thymic differentiation and prior to confrontation with the antigen (naive cells). After antigenic contact, usually in the lymphatic nodes, CD45RA + expression is lost and CD45RO is detected on the membrane of T cells (memory cells) [20,21]. Thus, in HIV/HCV co‐infected patients, the serial analysis of the TRECs and CD45 isoforms after treatment with IFN‐α and ribavirin could differentiate the modifications of T cells as attributable to a decrease in the thymic production or an effect of peripheral redistribution.…”