Antibody recognition of SpeA (L42R)-SpeB (C47S) fusion protein. A. Antibody recognition in vitro. Coomassie Blue stain of isolated SpeA (L42R)-SpeB (C47S), lane 1; Western blot using-affinity purified, rabbit anti-SpeB (lane 2) or anti-SpeA antibody (lane 3). B. Antibody response and recognition in vivo. Mice (BALB/c) were vaccinated three times with 10 μg of each protein and adjuvant (MPL), allowing two weeks between injections. Sera from each experimental group (n = 5) were pooled for measurement of specific antibodies. Data shown are antigen-specific antibodies (ELISA units) present in a 1:100,000 dilution of pooled sera from mice vaccinated with SpeA (L42R), SpeA (L42R)-SpeB (C47S) fusion or adjuvant only.