1Department of Microbiology, Guru Nanak Dev University, Amritsar.
2Emory Vaccine Center, Atlanta, USA.
Abstracts of the papers presented at the XVIII National Conference of Indian Virological Society at Post Graduate Institute of Medical Education and Research, Chandigarh, India, December 11–13, 2008.
Programed Death receptor (PD-1) is a member of CD28 superfamily of T Cell regulators. PD-1 is expressed on T Cell, B cell and Macrophage and more broadly regulates immune responses. Virus specific CD8 T cells play a critical role in the control of human immunodeficiency virus (HIV) and simian immunodeficiency virus (SIV). Both the functions and the frequency of antiviral CD8 T cells are crucial for the control of chronic viral infection. Effective antiviral CD8T cells possess a number of functional properties including the ability to produce different cytokines, cytotoxic potential, high proliferative potential and low apoptosis. We studied the temporal expression of PD-1 on SIV Gag-specific CD8T (Gag-CM9 tetramer) cell in blood, lymph node and rectal mucosal tissue following infection with pathogenic SIV239 using macaque SIV model. We also studied the temporal expression of PD-1 on SIV specific CD8 T cell in blood after vaccination with a replication defective DNA/modified Vaccinia virus Ankara (DNA/MVA) and after challenge with Mac 239 to understand relationship between PD-1 expression and viral control. PD-1 expression was predominantly restricted to memory cell and was absent on Naïve CD8 cells. Following infection the frequency of PD-1 positive CD8T cell did not change significantly over initial 12 weeks. However PD-1 expression on total CD8 T cells at 2 week after SIV infection the majority of SIV Gag CM9 tetramer specific CD8 T.
