Antigenic Similarity Between the Coccidian Parasites Toxoplasma gondii and Hammondia hammondi1

Abstract

The antigens present in the coccidian parasites T. gondii and H. hammondi were demonstrated and defined by using SDS-PAGE [sodium dodecyl sulfate polyacrylamide gel electrophoreisis] and immunoenzymatic techniques with 125I-labeled and unlabeled antigens of T. gondii and sea of mice infected orally or i.p. with H. hammondi. All cell surface antigens of T. gondii that were labeled with 125I were recognized by antibodies in the sera of the mice infected with H. hammondi except the antigen of .apprx. MW of 21.5 Kd. This antigen may be specific for T. gondii. Various antigens in the T. gondii-lysed antigen preparations were recognized by antibodies to H. hammondi. The number of recognized antigens increased as the infection of the mice with H. hammondi progressed. Oral infection with H. hammondi appeared to induce the formation of antibodies that recognized more T. gondii antigens than infection by i.p. inoculation.