Biologische Bundesanstalt für Land-und Forstwirtschaft, Institut für Pflanzenvirologie, Mikrobiologie und biologische Sicherheit, Braunschweig, Germany

Immunoelectron microscopy "IEM# and enzyme!linked immunosorbent assay "ELISA# studies with polyclonal antibodies "PAbs# indicated that the isolates 0A\ Nsabaand Kpeve of cacao swollen shoot virus "CSSV^ genus Badnavirus# are serologically distinct[ Out of these isolates\ only 0A was reliably detected from infected cacao trees with the homologous PAbs[ To improve sero! logical detection of the isolates Nsaba and Kpeve by the application of monoclonal antibodies "MAbs#\ virion preparations of CSSV!0A\ !Nsaba and !Kpeve were used to immunize mice[ Although immunization with CSSV! 0A yielded a large number of 0A!speci_c MAbs\ no Nsa! ba! or Kpeve!speci_c MAbs were obtained after immu! nization with these isolates[ Instead\ the latter exclusively led to the production of MAbs which reacted only with isolate 0A[ Epitope characterization of 0A!speci_c MAbs using di}erent ELISA procedures\ IEM and Western blot experiments showed that three of the 0A!speci_c MAbs detected a continuous epitope sodium dodecyl sulphate "SDS#!stable and nine MAbs reacted with conformation! dependent epitopes "SDS!labile#[ Direct adsorption of virus particles to microtitre plates in antigen!coated plate ELISA a}ected epitope stability in a similar fashion as SDS treatment of virions[ When comparing the sensitivity of CSSV detection by MAbs and PAbs in various ELISA formats\ MAbs were slightly more sensitive than PAbs in CSSV detection from plant sap[ Using the panel of available 0A!speci_c MAbs for triple antibody sandwich! ELISA analysis of 20 CSSV samples from di}erent cacao growing areas of Ghana revealed the occurrence of four serotypes in the samples containing CSSV!0A isolates[ In addition\ the serological reaction patterns of the MAbs correlated well with the geographic origin of the isolatesU[ S[ Copyright Clearance Center Code Statement] 9820 0674:88:3601 9614 , 03[99:9 thus giving further indications about the regional dis! tribution of CSSV 0A!like isolates in Ghana[