Antigenic differences between Blastocystis hominis and Blastocystis sp revealed by polyclonal and monoclonal

The antigenic differences between Blastocystis hominis and Blastocystis sp. (isolated from a human and a chicken sources, respectively) were investigated by using polyclonal and monoclonal antibodies, Polyclonal antibodies did not reveal distinct antigenic differences between the strains by Western blot analysis, whereas monoclonal antibodies (MAbs) produced against B. hominis did detect antigenic polymorphism between B. hominis and Blastocystis sp, Six out of 8 MAbs were specific to B. hominis antigens and 2 MAbs reacted with both B. hominis and Blastocystis sp, antigens, Immunoelectron microscopy using these MAbs, revealed labeling on the filamentous layer or the central vacuole, Interestingly, the 6 MAbs reacted only with B. hominis antigens on the filamentous layer, whereas the other 2 MAbs labeled on the central vacuole, Therefore, the antigenic components of the filamentous layer may be strain or species specific. In contrast, the antigenic components of the central vacuole are shared by both B. hominis and Blastocystis sp, suggesting the metabolic substances in the central vacuole are antigenically common.