Brett Leav, B. A., History,
Tufts University, Medford, MA,
M.D., University of
Massachusetts, Worcester, MA
Assistant Professor of Medicine
E-mail: bleav@tufts-nemc.org

My studies are focused on early mucosal immune responses to C. parvum. Using a murine model of cryptosporidiosis, I have shown that the early immune response to the parasite is dependent on interferon gamma (IFNγ). Iincreased mucosal expression of IFNγ occurs within 24 hours after infection with the parasite and CD8α TCRαβ intraepithelial lymphocytes are activated to secrete IFNγ. This response is consistent with an innate immune response and I am currently investigating the mechanisms underlying this phenomenon. These observations could lead to the discovery of parasite-derived substances that possess adjuvant properties, which could be used in the treatment of cryptosporidiosis, a disease for which there is no consistently effective therapy.

I am also studying the adaptive immune response to the commensal and probiotic microorganism, Lactobacillus rhamnosus GG (LGG). LGG is sold as a dietary supplement and efficaciously used to treat atopic dermatitis and infectious diarrhea in children. To understand the mechanism by which LGG and other probiotics exert beneficial effects, I have conducted a placebo-controlled blinded clinical trial in healthy, human volunteers who were given LGG. I am currently trying to determine if LGG promotes specific cell-mediated or humoral immune responses.