The antigens of Trichomonas foetus isolated from cows and pigs

Abstract

The serological properties of the two strains of Trichomonas foetus (strain B and strain M) isolated from uterine infections in cows in Belfast and in northern England, respectively, and two strains isolated from the caecum of pigs were in vestigated with rabbit antisera to each of the four strains by direct agglutination and by precipitation of a saline extract of the dired organisms in tubes and in gel-diffusion plates.There was considerable cross-reaction between the four strains. By the use of predominantly polysaccharide fractions from strains B and M and the predominantly protein fraction TF 4 from stratin B, the polysaccharide complex of lines could be distinguished from the protein lines.The major protein antigens were common to all four strains, but the major polysaccharide antigens were only partially shared.The cow strains B and M were readily distinguished from each other but had a variable though slight serological relationship. The two pig strains were very closely related to each other but were not identical. Cross-reaction revealed a relation between the cow and the pig strains. The cow strain B was more closely related than the M strain to the pig strains.The serological distinctions do not justify the separation of the pig and the cow strains of T. foetus into two species.I wish to thank Prof. W. T. J. Morgan, F.R.S. for preparations of diethylene glycol extracts and kind advice and Dr Winifred Watkins for ethanol fractionation of antigen and for enzyme preparations. I am also grateful to Dr A. E. Pierce of the Institute of Animal Physiology at Babraham for the isolation of clones from the S2 strain.