Catherine Crosby, Ph.D.

Our research goals are to better understand the immune responses generated against the bacteria Streptococcus pneumoniae, which causes serious lung infections. We have particular interest in the role of a highly specialized immune cell type called the invariant Natural Killer T Cell, which has been shown to be critical for protection against S. pneumoniae in mice. We are investigating how activation of these cells affects other cell populations in the lungs, which destroy the bacteria to clear the infection. This will help us understand how this population, and perhaps other similar cell types, helps protect humans from S. pneumoniae. This could lead to better treatments and vaccines against pathogens that enter through the lungs.

Update: We have made significant progress in understanding the activation of invariant Natural Killer T Cell (iNKT) subsets during pulmonary Streptococcus pneumoniae infection. Two subsets of iNKT cells, NKT1 and NKT17 cells, are recruited into the lung tissue within 24 hours of infection. NKT17 cells are activated during Streptococcus pneumoniae infection. Most of the NKT17 cells in the lungs are activated and/or produce a protein called IL-17A cytokine within 14 hours after infection, very early after infection. Notably, this protein has previously been shown to be a critical player in the protective immune response against S. pneumoniae. Until now, relatively little has been known about the roles of NKT17 cells, thus our data is novel by suggesting NKT17 cells could be critical players in the protective immune response against Streptococcus pneumoniae.