Poster Presentation Australasian Society for Immunology Annual Scientific Meeting 2014

Primary immune responses to vaccinia virus vaccination: role of cytotoxic effector CD4+ T cells in the generation of human T cell memory (#343)

Cynthia Mee Ling Munier 1 , Susanna Ip 1 , Michelle Bailey 1 , Yin Xu 1 , Sue Min Liu 2 , Gareth Denyer 3 , David A Cooper 1 , Stephen J Kent 4 , John J Zaunders 1 5 , Anthony D Kelleher 1 5
  1. The Kirby Institute, UNSW Australia, Sydney, NSW, Australia
  2. The Garvan Institute, Sydney, NSW, Australia
  3. The University of Sydney, Sydney, NSW, Australia
  4. The University of Melbourne, Melbourne, VIC, Australia
  5. St Vincent's Hospital, Sydney, NSW, Australia

Background: To understand the developmental stages of CD4+ T cell responses to viral infection and their differentiation into long-term memory cells, we studied individuals receiving primary vaccinia virus (VV) vaccination. This provides an attractive model for the study of human antiviral T cell responses as vaccination results in an acute infection that is cleared and leads to long-term protective immunity.

Method: At the peak of the primary effector cell response to VV, day 13 post-vaccination, we purified activated effector (CD45RO+CD38+++) and naïve (CD45RO-CD38dim) CD4+ T cells from 2 subjects, extracted mRNA and conducted microarray analysis using the Affymetrix, HU133 Plus 2.0 microarray.

Results: In the activated effector CD4+ compared to naïve CD4+ T cells many of the genes up-regulated were associated with cell division and activation, such as Ki-67, CD38 and CCR5, as expected, hence validating the arrays. Surprisingly, there was a strong up-regulation of cytotoxic T-lymphocyte (CTL) associated genes in the activated effector CD4+ T cells. Of the top 40 differentially expressed genes granzyme K ranked 1st with fold change (fc) of 40 compared to naïve CD4+ T cells. Killer cell lectin-like receptor subfamily B member 1 (KLRB1/CD161):4th (fc:26.3), Rab27a:19th (fc:8.2), granzyme A:26th (fc:13.9) and granulysin:36th (fc:7.9). These findings were confirmed by qPCR and flow.

Conclusion: Generation of anti-viral human CD4+ T cell memory during primary immune responses is poorly understood. The role of CTL associated genes in this process has not been explored. Understanding their role in the generation of an effective memory may lead us closer to the development of more effective vaccines for diseases such as HIV.