Analysis of spore extracts from 11 B. anthracis strains. Proteins were separated by SDS-7% PAGE and analyzed by immunoblotting with anti-BclA monoclonal antibody. Lane 1, strain 7702; lane 2, strain 8189; lane 3, strain 53169; lane 4, strain 9602R; lane 5, strain A2R; lane 6, strain 6183R; lane 7, strain 6602; lane 8, strain RA3R; lane 9, strain 7611R; lane 10, strain 5725R; lane 11, strain 4229. The sizes of the molecular mass markers are given in kilodaltons in the left margin.