Professor, Department of Pediatrics, McGill University
Director, Division of Allergy & Immunology, Montreal Children’s Hospital
Deputy Executive Director / Deputy Chief Scientific Officer of the RI-MUHC
Head of Child Health Research at the Montreal Children’s Hospital of the MUHC
B cells, immunoglobulins, innate immunity and the cytokine network
I am a pediatric allergist and immunologist based at the Meakins Christie Laboratories. I am also the division head of Allergy and Immunology at the Montreal Children’s Hospital. My research is centered around B-lymphocytes, the cells that make antibodies, and IgE, the antibody that initiates the allergic cascade in humans and that plays a crucial role in asthma, allergic rhinitis and anaphylaxis. My main projects include:
IL-13 and IL-13 Receptors in allergic inflammation: Did you know that B cells produce IL-13 as part of an autocrine loop that influences the synthesis of IgE ? (Hajoui et al, JACI 2004). We are continuing to define the role of the cytokine IL-13 in the maturation of B lymphocytes and the development of memory B cells and plasma cells. This work, funded by CIHR, utilized human cell culture techniques to attack early and late events in B cell development. We use cellular, molecular and flow cytometry techniques to understand how the IL-13 axis specifically changes the program of a B cell to become more pro-inflammatory. In addition, we have found that the Bc ell pro-inflammatory cytokine network extends to IL-9 and IL-25 (IL-17E) in parallel studies we have undertaken.
Intravenous immune globulin (IVIG) and Ig receptors:The immune system uses antibodies not only to trap antigens but to regulate immune processes. Our laboratory has extensively studies the action of IVIG on IgE synthesis. We are now evaluating the action of IVIG in murine airway hyperreactivity, addressing its role on dendritic cells as well as on pulmonary T and B cell trafficking. We have determined that the distribution of Fc receptors is beyond the tradition immune cells; in fact pulmonary epithelium is likely in import tissue that is influenced by both IgG and IgE. We are currently addressing the function of Fc receptors on pulmonary epithelial cells and the role of B cells in activating the pulmonary epithelium.
Tol Receptor 4 expression in Pediatric population: In work Supported by ALLERGEN-National center of excellence, in collaboration with Dr Qutayba Hamid, James Martin and Ronald Gehr, we have been able to phenotype the cell population that express the innate immune receptor TLR-4. The distribution of this receptor is much greater in children than adults and this has led to some novel determinations in cell populations responsible for cytokine production and innate immune responses. Further work will help us elucidate many facets of the hygiene hypothesis.
Chronic Beryllium Disease (CBD): In collaboration with Dr. Joseph Zeyed of the Université de Montréal and others, we have developed a murine model of CDB. This granulomatous pulmonary disease is a major occupational health hazard for individuals in many manufacturing and mining sectors.
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Education & Training
BA, Jewish Theol Sem America, 1980
BSc, Columbia U, 1980
MD, McGill, 1984