1. Department of Biology, College of Science and Technology, Temple University, Philadelphia, Pennsylvania 19122, Lung Biology Center, Department of Medicine, University of California, San Francisco, CA 94110, Alistair Reid Venom Research Unit, Liverpool School of Tropical Medicine, Pembroke Place, Liverpool L3 5QA, U.K., and Instituto de Biomedicina de Valencia, CSIC, E-46010 Valencia, Spain