ROLE OF CD48 IN REGULATION OF T-CELL MEDIATED IMMUNITY IN HTLV-1 INFECTION

Abstract

Event Abstract Back to Event ROLE OF CD48 IN REGULATION OF T-CELL MEDIATED IMMUNITY IN HTLV-1 INFECTION Chioma E. Chibueze-Nnorom1, Yohann White2, Makoto Yoshimitsu1* and Naomichi Arima1* 1 Center for Chronic Viral Diseases Graduate School of Medical and Dental Sciences Kagoshima University, Hematology and Immunology, Japan 2 University of West Indies, Mona Kingston, Jamaica HTLV-1 (Human T cell lymphotropic virus type 1) infection is associated with an aggressive T cell malignancy ATLL (Adult T-cell leukemia/lymphoma), the virus also establishes lifelong persistent infection in humans resulting in a carrier state (clinically asymptomatic). CD48 is a GPI anchored cell surface molecule ubiquitously expressed on various hematopoietic cells, its expression has been shown to be up-regulated in viral infections as a sign of ongoing breach of immunity and therefore facilitates immune response. In HTLV-1 infection, one of the factors suggested to play a role in its persistence is the increased expression of the trans-activating viral gene encoding HTLV-1 tax among others; tax protein is the dominant target antigen of the T cell response to HTLV-1 in infected individuals. In this study, we investigate the role of CD48 in HTLV-infection, we show that it is down regulated in HTLV-1 infection; the presence of HTLV-1 tax protein also suppresses CD48 expression. On blockade using anti-CD48 AB (antibody), the effector function of T cells in terms of cytokine production improved. Thus, we propose a possible means of immune evasion by HTLV-1 virus by Cd48 down-regulation and a possible inhibitory role in HTLV-1 infection.