Uterine Mast Cells and Immunoglobulin-E Antibody Responses During Clearance ofTritrichomonas foetus

Abstract

Abstract. We showed earlier that Tritrichomonas foetus-specific bovine immunoglobulin (Ig)G1 and IgA antibodies in uterine and vaginal secretions are correlated with clearance of this sexually transmitted infection. Eosinophils have been noted in previous studies of bovine trichomoniasis but the role of mast cells and IgE responses have not been reported. The hypothesis that IgE and mast cell degranulation play a role in clearance was tested in 25 virgin heifers inseminated experimentally and infected intravaginally with T. foetus strain D1 at estrus and cultured weekly. Groups were euthanatized at 3, 6, 9, or 12 weeks, when tissues were fixed and secretions were collected for culture and antibody analysis. Immunohistochemistry using a monoclonal antibody to a soluble lipophosphoglycan (LPG)-containing surface antigen (TF1.17) demonstrated antigen uptake by uterine epithelial cells. Lymphoid nodules were detected below antigen-positive epithelium. Little IgG2 antibody was detected but IgG1, IgA, IgM, and IgE T. foetus-specific antibodies increased in uterine secretions at weeks 6 and 9 after infection. This was inversely proportional to subepithelial mast cells numbers and most animals cleared the infection by the sampling time after the lowest mast cell count. Furthermore, soluble antigen was found in uterine epithelium above inductive sites (lymphoid nodules). Cross-linking of IgE on mast cells by antigen and perhaps LPG triggering appears to have resulted in degranulation. Released cytokines may account for production of predominantly Th2 (IgG1 and IgE) and IgA antibody responses, which are related to clearance of the infection.

Mucosal Veterinary Vaccines

“…Immunostaining of parallel sections with mAb to TF1.17 antigen indicated uptake of antigen by epithelial cells and large MΦ or DC under the basement membrane near the lymphoid follicles (Rhyan et al, 1999). Similar antigen uptake has been detected in the infected female uterine and vaginal mucosa (Corbeil et al, 2005). Thus, even though the parasite is noninvasive, released TF1.17 antigen appears to be taken up by epithelial cells.…”

“…Parsonson et al (1976) showed that significant inflammation accompanied by reproductive failure did not occur until after 7 weeks of infection, so the vaccine should protect against fetal loss. Analysis of vaccine-induced antibody responses demonstrated predominantly IgG1 responses in the serum and IgA plus IgG1 antibodies in secretions (Corbeil et al, , 2005. IgE antibodies were also increased during infection.…”

Murine Models of Vaginal Trichomonad Infections

“…Experimental infection of female cattle with T. foetus (strain D1) can be detected by vaginal cultures for many weeks or months. 4,10,28 Because comparative data on experimental infection with T. vaginalis in humans are not available, it is possible that T. vaginalis infection of the even the natural host is less persistent than that of T. foetus . Pretreatment of mice with steroids and sex hormones was critical for achieving robust and extended vaginal infections with T. vaginalis.…”

A Pregnant Mouse Model for BovineTritrichomonas foetusInfection

“…Their prominence in T. foetus infection in cattle has been noted in several studies. 1,5,16,18,46 Their tissue damaging granules can have bystander effects on local tissues and marked vascular effects that lead to edema, although a specific role of eosinophils in trichomoniasis has not been determined. 26 However, their vascular effects could well contribute to the transport of antibodies to the uterine and vaginal lumen, and provide some protection from infection and later clearance of trichomonads.…”

“…58 This strain, at a dose of 1 3 10 6 T. foetus organisms intravaginally instilled, was used in several studies to intravaginally infect 100% of experimental heifers at estrus. 10,16 Parasites were maintained in culture by using trypticase-yeast extract-maltose (TYM) medium that contained 10% fetal calf serum until inoculation. 22 A mouse-adapted strain of T. foetus (MuTF 52100V) was developed by first intravaginally infecting BALB/ cAnNCr mice with strain D1.…”