Previous studies from this laboratory have suggested the presence of antibody-binding molecules on the surface of Taenia crassiceps metacestodes. We now report the purification of a T. crassiceps Fc gamma-binding protein which has an equivalent molecular size (96 kDa), is antigenically similar and exhibits significant amino acid sequence homology to schistosome paramyosin. The similarities in molecular weight of the T. crassiceps protein, Schistosoma mansoni paramyosin and antigen B of T. solium, the close amino acid sequence homologies between the T. crassiceps protein and S. mansoni paramyosin and between S. mansoni paramyosin and antigen B of T. solium, and the antigenic similarity of the T. crassiceps protein with paramyosin indicates that this family of platyhelminth proteins are closely related. The known characteristics of T. solium antigen B (collagen binding affinity; disruption of complement function) and the Fc gamma-binding activity of the T. crassiceps molecule suggests that this class of proteins may be multifunctional, fulfilling not only a structural role but also as components interacting with the host immune system to increase parasite survival.