In the bovine trichomoniasis experimental model, systemic immunisation, unlike preputial infection, induces protection against trichomonad colonisation in bulls
Abstract number: P1931
Cobo E., Corbeil L., BonDurant R.
Trichomonads cause human and bovine sexually-transmitted infections, with adverse outcomes of pregnancy in both host species. Bovine trichomoniasis is a useful model because it resembles human trichomoniasis in many ways. Like Trichomonas vaginalis, Tritrichomonas foetus (T. foetus) is an extracellular obligate protozoon that persistently and asymptomatically colonizes the genital tract in males although trichomonad antigens are detected in the preputial mucosal epithelium. We described a preputial "silent" mode of responsiveness in bulls infected with T. foetus where males did not mount either a detectable preputial IgA, IgG, IgM or IgE antibody response or increase in immune-inflammatory cells, including mast cells, B, and T cells, and had a slightly increased tissue expression of TGF-beta. Only some T. foetus infected bulls showed eosinophilia in the preputial submucosa. However, this "sleeping beauty" mode of responsiveness could be awakened since bulls systemically vaccinated and later challenged with T. foetus were capable of resisting trichomonad mucosal colonisation by developing systemic and preputial T. foetus specific IgG1 and IgG2 responses. This IgG response was accompanied by an increased population of preputial submucosal HM57+B cells that may produce a portion of the IgG antibodies. In addition, mast cells in the submucosa may assist in transport of IgG from serum to genital lumen by releasing vasoactive inflammatory mediators. Also, in vaccinated and challenged bulls, an increased population of CD3+ T cells and a slightly increased expression of IL-5 in preputial mucosa were observed, suggesting amplified antigen processing and consequently a more productive immune response. Defining mechanisms to explain why the bovine male genital mucosa responds to T. foetus"silently" during infection but with an effective local and systemic IgG response after systemic immunisation may contribute to understanding the role of Trichomonas vaginalis in men.
|Session name:||18th European Congress of Clinical Microbiology and Infectious Diseases|
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