Generation of central memory T cells by vaccination that mimics natural infection (LYM5P.704)

Abstract

Abstract The goal of vaccination is to generate long-lived antigen specific memory T & B cells. Often we notice that the immune responses generated by the vaccines fail to achieve the desired goal, particularly the T cell responses. In many infection models it is well established that long-lived memory T cells could be generated in hosts exposed to pathogens through natural infection. Here we are adopting the strategies that would mimic natural infection with the hope to induce immune responses in a manner similar to that triggered during natural infection. In our study we have mimicked the natural infection to vaccinate the host by (i) providing the danger signals to the immune system before or during encounter of Ag to mimic the course of infection, (ii) combining non-target Ag(s) with target Ag, while priming the host in the presence of danger signals.We have used OVA as the model antigen to immunize C57BL/6 mice, and Poly I:C/R848 as danger signals to represent viral infection. For non-target antigens, we have used immunogenic (HEL) as well as non-immunogenic (MBP) antigens. We found that vaccination through mimicking course of infection favors generation of Central MemoryT cells whereas conventional vaccination favors effector memory T cells. When we mimicked natural infection to vaccinate the host by including poorly immunogenic non-target antigen with the vaccine target we found it to favor generation of central memory T cells compared to that of immunogenic non- target.