Immunoprecipitation of 35S-labeled B. bigemina proteins. Proteins labeled with [35S]methionine during in vitro growth of B. bigemina were immunoprecipitated with MAb 64/32 (lane 4), MAb 14/16 (anti-p58, RAP-1) (lane 5), murine polyclonal antiserum to p94 (lane 2), bovine postinfection serum B240 (lane 3), or preinoculation murine serum (lane 1). Molecular size standards are designated on the left.