UNUSUAL DISTRIBUTION OF A GLYCOLIPID ANTIGEN IN THE FLAGELLA OF CHLAMYDOMONAS

Mouse hybridomas were obtained that secrete monoclonal antibodies recognizing glycolipid antigens located in the flagellar membrane of the biflagellate alga, Chlamydomonas reinhardtii. The antigen is an acidic lipid that migrates slightly slower than a GM1 ganglioside on thin layer chromotography. The binding of the antibodies to the thin layer plate was inhibited by periodate oxidation suggesting that the antibodies are recognizing a carbohydrate epitope. In a variety of Chlamydomonas strains, these antibodies were found to stain the flagella of only a sub-set of the cells in the population, generally varying from 50% to 75% of the cells. Even after cloning, the population of cells continued to express this variability in staining, and presumably, expression of the glycolipid epitope. Although most cells showed either strong staining of both flagella or no detectable staining of both flagella, a subset of the cells in the culture exhibited differential antibody labeling of the two flagella, suggesting that an individual Chlamydomonas can exhibit a different glycolipid composition in each of its two flagellar membranes and even differential expression along the length of an individual flagellum.