POLYCLONAL ANTISERA TO DISTINGUISH STRAINS AND FORM VARIANTS OF PHOTORHABDUS (XENORHABDUS) LUMINESCENS

In this study antisera against Photorhabdus luminescens strains were p repared for the first time. P. luminescens is a bacterial symbiont of entomopathogenic nematodes belonging to the genus Heterorhabditis. To characterize P. luminescens strains and form variants, we produced pol yclonal antisera against P. luminescens PE (obtained from nematode str ain NLH-E87.3) and against the primary and secondary forms of P. lumin escens PSH (obtained from nematode strain DH-SH1). In double-diffusion tests all form variants of strain PE reacted with the antiserum again st the primary form, but each variant produced a different diffusion p attern. The primary and secondary forms of strain PSH were also serolo gically different. Antiserum 9226 reacted with almost all P. luminesce ns strains tested, but it reacted differently with each strain in the double-diffusion test, showing that the strains were serologically dif ferent. The specificity of the antisera was increased by cross-absorpt ion. After cross-absorption the antiserum against the strain PSH prima ry or secondary form was specific for that form and did not react with the other form. Using the cross-absorbed antisera in immunofluorescen ce cell-staining tests, we could distinguish primary and secondary for m cells in a mixed strain PSH culture.