M1 prime is a segment of IgE found only in the membrane form of IgE and not on soluble IgE found in serum. Membrane IgE (and M1prime) is expressed on IgE-switched B cells, IgE-memory B cels, and IgE-plasmablasts. Depletion of IgE-switched B cells and plasmablasts will reduce IgE-producing cells and serum IgE, and may be a target for treatment of allergic asthma. A humanized antibody targeting M1 prime is being developed by Genentech, Inc., as a potential therapeutic for asthma.~Currently, the efficacy of MEMP1972A is being assessed in an allergen challenge study in mild asthmatics (MOP4843g). Extensive biomarker samples have been incorporated in that study to characterize the mechanism of action (MOA) as well as the kinetics of the MOA of MEMP1972A, which are poorly understood at this time. Furthermore, samples for the B cell enriched peripheral blood flow cytometry and bone marrow aspirates to evaluate the kinetics and MOA of MEMP1972a are collected only 24 hr after allergen challenge due to visit and sample volume limitations. It is known that maximal B cell responses are expected ~7 days after allergen stimulation. Therefore, the purpose of this research study will be to characterize the time course of B cell activation after allergen challenge, and more specifically measure the M1 prime related biomarkers.
The purpose of this study is to characterize the time course of B cell activation after allergen challenge, and more specifically measure the M1 prime related biomarkers.