Endospore heterogeneity in Pasteuria penetrans related to adhesion to plant-parasitic nematodes

Hybridoma cell lines were screened by indirect immunofluorescence for the secretion of monoclonal antibodies (Mabs) to the surface of a population of endospores of the obligate nematode hyperparasite Pasteuria penetrans. Whereas polyclonal antibodies from test sera samples recognized 100% of the spores, five selected Mabs recognized different proportions of the spores ranging from 10 to 90% showing that the spore population was highly heterogeneous. Probing spores adhering to different nematode populations with the five Mabs showed that different subpopulations of the spores were specific to different nematode populations indicating cuticular heterogeneity among the nematode populations. Each of the five Mabs recognized a far larger proportion of the spores adhering to the nematode population on which the Pasteuria population was originally cultured than of those adhering to other populations.