Worm Breeder's Gazette 9(1): 55
These abstracts should not be cited in bibliographies. Material contained herein should be treated as personal communication and should be cited as such only with the consent of the author.
As an initial means of investigating germ cell determination in Ascaris des, I have begun to produce monoclonal antibodies using homogenates of fertilized Ascaris eggs as the immunogen. Two spleens of immunized C57B1/6 mice were fused with P3. 653 myeloma cells. Supernatants of the resulting 193 hybridoma colonies were first screened by indirect radioimmune assay for binding to egg homogenates. The 83 positive cell lines were frozen away, while their hybridoma supernatants have been further characterized. It was brought to my attention that phosphorylcholine is immunodominant in nematode infections (Jour. of Immunol.(1985) 134:1172-1177. and Jour. of Immunol.(1976) 116 1105-1109.) Therefore the positive antibodies were then screened in a competitive binding assay against soluble phosphorylcholine. Almost half of the cell lines tested, (and most of the 'best binders' in the solid phase assay) , could be competed with phosphorylcholine and are tentatively identified as being directed against this molecule. As a collaborative effort with Susan Strome, the 43 remaining hybridomas were screened on C. elegans and Ascaris eggs which had been cracked in liquid nitrogen and fixed with methanol and acetone (Strome and Wood, (1982) P.N.A.S. 79 1558-1562.). We found that Ascaris egg membranes are not permeablized by this technique (as monitored by the lack of binding with an alpha-tubulin antibody), however in screening the C. elegans embryos, 8/43 supernatants from the Ascaris antibodies bind to the germ cell P-granules of C. elegans with varying degrees of intensity. Supernatants from another 5/43 of the Ascaris lines bind to other tissues in the C. elegans embryo, including the cuticle and what appears to be nerve. The rest of the Ascaris antibodies were negative for binding C. elegans embryos. We are currently working on means to permeabilize the Ascaris egg membranes to determine the specificities of these antibodies in Ascaris.