Ryan W. Nelson

     E-mail: nels5471@umn.edu

     Year Entered: 2007

     Degrees Received: 
     Washington University
     Anthropology and Biology majors
     B.A., 2007

     Honors and Awards:

     -NIH/NIDDK National Research Service Award for Individual
     Predoctoral MD/PhD Fellows, 2011-2015 

     Thesis Advisor: Marc Jenkins, Ph.D.

     Thesis Research: Recent work has demonstrated that memory CD4+ T
     cells decay following clearance of some acute bacterial infections. However, this issue has not been addressed for persistent bacterial infections where CD4+ T cells are the protective cell type. During persistent Salmonella infection in mice, CD4+ T cells control pathogen burden by activating infected macrophages and limiting bacteria to the gut draining mesenteric lymph nodes. Using a peptide:MHCII (p:MHCII)-tetramer based enrichment strategy, we track a polyclonal Salmonella p:MHCII-specific CD4+ T cell response to intragastric infection. We have found that Salmonella p:MHCII-specific T cells are maintained at a numerically stable level throughout persistent infection but decay if the infection is cleared. This population consists of highly functional Th1 cells capable of producing IFN-γ and TNF-α upon re-stimulation. These results indicate that localized p:MHCII presentation in the chronically infected mesenteric lymph nodes is the key to maintaining this naturally stable CD4+ T cell response to Salmonella and simultaneously avoiding exhaustion.

Jenkins lab

Publications Prior to Entering MD/PhD Program:
Bush, L. A., Nelson, R. W., and Di Cera, E. Murine thrombin lacks Na+ activation but retains high catalytic activity J Biol Chem. 2006;281: 7183-7188.