Production of polyclonal antibodies for cyclopaldic acid, a major phytotoxic metabolite produced by the plant pathogen Seiridium cupressi.

An antiserum against cyclopaldic acid (CA), a phytotoxic metabolite produced by Seiridium cupressi, the fungal pathogen of a canker disease of cypress, was prepared by immunization of rabbits with a CA-bovine serum albumin conjugate (CA-BSA). Antibodies recognizing CA were purified by affinity chromatography through an immunoadsorbent prepared by conjugating CA to lysine-Sepharose 4B. The specificity of antibodies was assayed against CA and some of its derivatives by competitive indirect enzyme-linked immunoassay. The homologous antigen CA-BSA and CA showed the highest binding activity with antibodies. The derivatives of CA modified in 1 of the 2 aldehyde groups reacted with antibodies to a lesser extent compared with CA-BSA and CA. Isocyclopaldic acid and the tetraacetylderivative of CA, which have more than one modified functional group, showed a further decrease in their reactivity. Other derivatives, which have more substantial structural modifications of the carbon skeleton, did not react. The possible use of these antibodies in studies concerning the involvement of CA in the canker disease of cypress is discussed.