Analysis of the Antigenic Relationships Among Trichomonas, Histomonas, Dientamoeba, and Entamoeba.* II. Gel Diffusion Methods

SYNOPSIS. Antisera were developed in rabbits against Trichomonas gallinae, Histomonas meleagridis, Dientamoeba fragilis, Entamoeba invadens, and Entamoeba histolytica. In reactions between these antisera and antigens prepared from each of the 5 species the most numerous and strongest precipitin lines appeared on gel diffusion agarose plates between the homologous antigens and antisera. Anti‐Trichomonas serum cross‐reacted most strongly with Histomonas, somewhat less with Dientamoeba, but gave no lines with the 2 species of Entamoeba. Anti‐Histomonas serum cross‐reacted strongly with both Trichomonas and Dientamoeba, and weakly with E. invadens and E. histolytica. Dientamoeba antiserum gave many precipitin lines with Histomonas, fewer with Trichomonas, and fewest with the 2 species of Entamoeba. Stronger reactions were noted between anti‐Dientamoeba serum and E. invadens than between this serum and E. histolytica. Immune sera prepared against the 2 species of Entamoeba gave the most numerous precipitin lines in intrageneric cross‐reactions, but the reaction between either of these antisera and Histomonas was weak. Somewhat stronger reactions were observed between the 2 anti‐Entamoeba sera and Dientamoeba. Trichomonas failed to react with either of the anti‐Entamoeba sera.