arthritis-inducing agent streptococcal cell wall 2013-11-11T12:03:50Z A biologic agent consisting of a more or less purified preparation of cell walls from streptococcus bacteria. Streptococcus is a genus of spherical Gram-positive bacteria belonging to the phylum Firmicutes and the lactic acid bacteria group. The cell wall is the rigid structure that lies just outside of and is joined to the plasma membrane of plant cells and most prokaryotic cells, which protects the cell and maintains its shape. SCW XCO:0000350 experimental_condition_ontology jsmith