W. Allan Walker, M.D.

My research efforts include defining the passive and active protective properties of human breast milk with regard to the protection from disease during the newborn period. I also study the development of human intestinal host defenses using human fetal organ cultures, cell lines, and xenograft transplant models.

Specifically, my laboratory has reported that the human fetal epithelium responds inappropriately to both endotoxin and exotoxins, which helps to explain an increased incidence and severity of certain inflammatory and secretory diarrheas in this age group.

More recently, we have studied the effect of initial colonizing microbiota on the development of mucosal protective function and the mechanism of probiotics in this process.

Until January 2013, I was responsible for overseeing the Mucosal Immunology and Developmental Gastroenterology Laboratories as part of the Gastroenterology and Nutrition Division at MGHfC at Harvard Medical School, which is now the Mucosal Immunology and Biology Research Center, headed by Dr. Alessio Fasano.