The IIDR has awarded the Bowdish lab seed money to study the role of macrophages in host response to colonization by Streptococcus pneumoniae. S. pneumoniae infections can range from treatable (respiratory tract infections, otitis) to life-threatening (meningitis, sepsis). The introduction of the pneumococcal conjugate vaccine (PCV) has shifted the epidemiology of S. pneumoniae infections but not eliminated them.  In humans, colonization of the upper respiratory tract is the initial step in pathogenesis. This is accompanied by a robust antibody response, which is generally believed to be required for clearance (and thus prevention of infection); however, data for this is not supported by clinical observations in which high levels of antibodies are not associated with clearance or in which immunodeficient patients susceptible to pneumococcal infections can produce robust anti-pneumococcal antibody responses while still being prone to recurrent systemic infections.  The aim of this project is to assess the importance of macrophages in the recognition and clearance of S. pneumoniae in the upper respiratory tract.   This work will be done in collaboration with Prof. Jeffrey Weiser at the University of Pennsylvania who is a world leader in the field of S. pneumoniae pathogenesis. Dawn will be travelling to his lab in July to learn from his lab members.  The Bowdish lab is currently recruiting graduate students and post-docs who are interested in the host response to S. pneumoniae infection and colonization.