The pinewood nematode (PWN, Bursaphelenchus xylophilus) is known as a virulent factor of the pine wilt disease, transmitted to pinewoods by the pine sawyer beetle, Monochamus alternatus. It is very hard to discriminate B. xylophilus from B. mucronatus because these Bursaphelenchus species are genetically and biochemically very close. Therefore, it has been necessary to detect PWN-infected trees for the prevention of pine wilt disease transmission in a short time. We developed polyclonal antibodies against B. xylophilus in BalbC mice and primarily screened with ELISA. Positive clones releasing polyclonal antisera revealed B. xylophilus-specific immuno-reactivity, which were at least two times higher than that of B. mucronatus. Two clones, D9-F10 and 1F3, were finally selected and exhibited specific immuno-reactivity for B. xylophilus, not for B. mucronatus in Western blot analysis. D9-F10 clone was reactive with a 43-kDa whereas 1F3 clone with two proteins, 40- and 45-kDa. Their isotypes against mouse Ig family were identical, kappa-light chain. These results suggest that these monoclonal antibodies can be useful for the development of diagnostic kit for the pine wilt disease.

The pine sawyer beetle, Monochamus alternatus, transmits the pinewood nematode (PWN, Bursaphelenchus xylophilus), causing the pine wilt disease (PWD), which gives rise to enormously economic as well as forest damage. However, PWN has been identified as a pathogen of PWD, it is very difficult to discriminate B. xylophilus from B. mucronatus in a short time, which are genetically and morphologically very similar. Therefore, it has been necessary to detect and eliminate PWN-infected trees in the forest area for the prevention of PWD transmission. Up to date, there is no report on biomarkers such as DNA and protein for the diagnosis of B. xylophilus. In this study, we produced a B. xylophilus monoclonal antiserum (D9-F10) from BalbC mice and screened its specificity with various proteins extracts. Western blot analysis revealed that the D9-F10 is only reactive with B. xylophilus protein extract among other tested protein extracts, indicating that the D9-F10 is specific for a B. xylophilus protein. Furthermore, two-dimensional electrophoresis showed the D9-F10 detects a very highly acidic protein, pI≒3.5. These results suggest that the D9-F10 monoclonal antibody is useful for the development of a diagnostic kit for the pine wilt disease.

The pinewood nematode (PWN, Bursaphelenchus xylophilus) causes the pine wilt disease, transmitted to pinewoods by the pine sawyer beetle, Monochamus alternatus. It is very difficult to discriminate B. xylophilus from B. mucronatus. Therefore, it has been necessary to detect PWN-infected trees for the prevention of pine wilt disease transmission in a short time. The development of biomarkers such as DNA and protein is important for diagnosis of B. xylophilus. However, there have been no reports regarding biomarker identifications of B. xylophilus. In this study, polyclonal antisera were raised against whole proteins of B. xylophilus in BalbC mice and were primarily screened with ELISA. Twenty five among over 500 cell lines releasing polyclonal antisera revealed B. xylophilus-specific immuno-reactivity, which was at least three times higher than that of B. mucronatus. Three cell lines among them were secreting monoclonal antibody through further screening. These cell lines only detect about a 33-kDa protein in B. xylophilus in the western blot. These results suggest that these monoclonal antibodies will be useful for the development of diagnostic kit for the pine wilt disease.