Characterization of antigenic proteins from Tritrichomonas foetus recognized by antibodies in rabbit serum, bovine serum and bovine cervicovaginal mucus

Tritrichomonas foetus is an obligate parasite of the bovine urogenital trac t and is recognized as 1 of the more common infectious agents causing decre ased reproductive efficiency in beef cattle. Infections result in reproduct ive failure and produce considerable economic loss. Vaccination of heifers with vaccines containing T foctus induces elevated serological responses to many T. foetus antigens, decreases the rate and/or length of infection wit h T. foetus, and decreases fetal loss caused by infection. Because T. foetu s infections are usually limited to lumen and mucosal surfaces of the repro ductive tract, it has been assumed that protection from infection and abort ion is partially mediated by immunoglobulins in the uterus and vagina. The objective of this study was to identify and characterize specific antigens of T. foetus that show promise for use in a recombinant vaccine that will g enerate a protective mucosal immune response in cattle. Surface proteins we re identified by using polyclonal rabbit anti-trichomonal sera eluted from paraformaldehyde-fixed cells. Analyses of these proteins, utilizing mucosal antibodies from vaccinated and convalescent cows, have identified proteins involved in generating a local immune response. Western immunoblot analysi s indicates that these proteins are well conserved and are excellent candid ates for incorporation into a recombinant vaccine.