Production of Monospecific Antiserum Against the Blood Disease Bacterium Affecting Banana and Plantain

Proteins from the blood disease bacterium (BDB) affecting banana and plantain and proteins from other bacterial species were separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, blotted onto nitrocellulose membrane, and probed with polyclonal antibodies directed against BDB. A 33.5-kDa protein band was characteristic for all virulent strains of BDB examined. Monospecific antibodies obtained against this protein by affinity purification were specific for BDB. A second polyclonal antibody was raised against the gel-purified 33-kDa protein in a rabbit. The serum was termed monospecific antiserum (MSA) and was used in subsequent experiments. The MSA reacted specifically with all virulent strains of BDB in agglutination tests and colony blot tests but not or only weakly with Pseudomonas solanacearum, P. syzygii, and other bacterial species. The specificity of the MSA was confirmed in studies with banana plant extracts. BDB could be detected in all infected plants 3-33 days after inoculation, whereas plants inoculated with P. solanacearum race 2 did not react with the MSA on immunocolony blots