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

Mast cells proliferate in the peri-hippocampal space during early development and modulate local and peripheral immune cells

Brain development is a non-linear process of regionally specific epochs occurring during windows of sensitivity to endogenous and exogenous stimuli. We have identified an epoch in the neonatal rat brain defined by a transient population of peri-hippocampal mast cells (phMCs) that are abundant from birth through 2-weeks post-natal but absent thereafter. The phMCs are maintained by proliferation and harbor a unique transcriptome compared with mast cells residing in the skin, bone marrow, or other brain regions. Pharmacological activation of this population broadly increases blood-brain barrier permeability, recruits peripheral immune cells, and stunts local microglia proliferation. Examination of the post-mortem human brain demonstrated mast cells in the peri-hippocampal region of a newborn, but not an older infant, suggesting a similar developmental period exists in humans. Mast cells specifically, and early-life inflammation generally, have been linked to heightened risk for neurodevelopmental disorders, and these results demonstrate a plausible source of that risk.

Endometrial distribution of bovine immune cells in relation to days to conception after parturition

In dairy cows, the processes involved in the resolution of uterine inflammation during the postpartum are closely related to improved fertility during the subsequent lactation period. Little is known, however, about the role and distribution of endometrial immune cell populations during the pre-implantation period. This study was aimed to analyze the endometrial distribution of several mononuclear immune cells (T cells, γδ T cells, B cells and macrophages) in healthy dairy cows during the postpartum, beyond the transition period, looking for its possible association with the parturition-conception interval (PCI) and delayed conception. The quantification of immune cells was evaluated by immunohistochemistry (IHC), and the expression of hormone receptors in immune cells was evaluated by double IHC. Dairy cows were grouped according to their PCI: PCI shorter than or equal to 90 DIM (PCI≤90), PCI between 90 and 120 DIM (PCI90-120), and PCI greater than 150 DIM (PCI≥150). The distribution of endometrial mononuclear immune cells was analyzed by a Generalized Linear Model, and the association of the distribution of mononuclear immune cells with delayed conception was evaluated with a Kaplan-Meier test. The cows from the PCI90-120 group showed the highest number of endometrial macrophages, and a lower number of B cells than the PCI≤90 group. Results also showed an association between the lower number of B cells in the endometrium during the pre-implantation period and earlier conception. Also, the present findings indicates that ESR and PR are expressed in the endometrial MØ, T cells, γδ T cells and B cells.

Immune responses in the uterine mucosa: clues for vaccine development in pigs

The immune system in the upper reproductive tract (URT) protects against sexually transmitted pathogens, while at the same time providing immune tolerance responses against allogenic sperm and the developing fetus. The uterine environment is also responsive to hormonal variations during the estrus cycle, although the most likely timing of exposure to pathogens is during estrus and breeding when the cervix is semi-permissive. The goal for intrauterine immunization would be to induce local or systemic immunity and/or to promote colostral/lactogenic immunity that will passively protect suckling offspring. The developing fetus is not the vaccine target. This minireview article focuses on the immune response induced in the pig uterus (uterine body and uterine horns) with some comparative references to other livestock species, mice, and humans.

Mast cells-fetal mast cells crosstalk with maternal interfaces during pregnancy: Friend or foe?

Mast cells (MC) are hematopoietic immune cells that play a major role during allergic reactions in adults by releasing a myriad of vasoactive and inflammatory mediators. MC seed all vascularized tissues and are most prominent in organs with a barrier function such as skin, lungs, and intestines. These secreted molecules cause mild symptoms such as localized itchiness and sneezing to life-threatening symptoms (i.e., anaphylactic shock). Presently, despite the extensive research on Th2-mediated immune responses in allergic diseases in adults, we are still unable to determine the mechanisms of the role of MC in developing pediatric allergic (PA) disorders. In this review, we will summarize the most recent findings on the origin of MC and discuss the underappreciated contribution of MC in the sensitization phase to maternal antibodies during pregnancy in allergic reactions and other diseases such as infectious diseases. Then, we will lay out potential MC-dependent therapeutic strategies to be considered in future investigations to understand the remaining gaps in MC research for a better quality of life for these young patients.

A review of sexually transmitted bovine trichomoniasis and campylobacteriosis affecting cattle reproductive health

The objective is to discuss sexually transmitted diseases caused by Tritrichomonas foetus (T foetus) and Campylobacter fetus (C fetus) subsp. venerealis, with a focus on prevalence, pathogenesis, and diagnosis in cows and bulls. Diagnosis and control are problematic because these diseases cause severe reproductive losses in cows, but in bulls are clinically asymptomatic, which allows the disease to flourish, especially in the absence of legislated control programs. We review research regarding prophylactic systemic immunization of bulls and cows with antigens of T foetus and C fetus venerealis and their efficacy in preventing or clearing preexisting infections in the genital tract. Current diagnostic methods of C fetus venerealis and T foetus (microbial culture and PCR) should be improved. Review of the latest advances in bovine trichomoniasis and campylobacteriosis should promote knowledge and provide an impetus to pursue further efforts to control bovine sexually transmitted diseases.

Trichomonas vaginalis infection induces vaginal CD4+ T-cell infiltration in a mouse model: a vaccine strategy to reduce vaginal infection and HIV transmission

BACKGROUND

Complications related to the diagnosis and treatment of Trichomonas vaginalis infection, as well as the association between T. vaginalis infection and increased transmission of and susceptibility to human immunodeficiency virus, highlight the need for alternative interventions. We tested a human-safe, aluminum hydroxide-adjuvanted whole-cell T. vaginalis vaccine for efficacy in a BALB/c mouse model of vaginal infection.

METHODS

A whole-cell T. vaginalis vaccine was administered subcutaneously to BALB/c mice, using a prime-boost vaccination schedule. CD4(+) T-cell infiltration in the murine vaginal tissue and local and systemic levels of immunoglobulins were measured at time points up to 4 weeks following infection.

RESULTS

Vaccination reduced the incidence and increased the clearance of T. vaginalis infection and induced both systemic and local humoral immune responses. CD4(+) T cells were detected in vaginal tissues following intravaginal infection with T. vaginalis but were not seen in uninfected mice. The presence of CD4(+) T cells following T. vaginalis infection can potentially increase susceptibility to and transmission of human immunodeficiency virus.

CONCLUSIONS

The vaccine induces local and systemic immune responses and confers significantly greater protection against vaginal infection than seen in unvaccinated mice (P < .005). These data support the potential for a human vaccine against T. vaginalis infection that could also influence the incidence of human immunodeficiency virus infection.

Current status and prospects for development of a vaccine against Trichomonas vaginalis infections

Trichomonas vaginalis is a sexually transmitted pathogen with an annual worldwide incidence of over 276 million infections, the highest of all curable and non-viral STI. A large proportion of cases are asymptomatic and under-diagnosed with conventional diagnostic tools. Infection has important maternal and fetal health consequences and can lead to a higher probability of HIV transmission and susceptibility. Lack of affordable accurate diagnostic tests globally and metronidazole resistance hinder T. vaginalis control efforts. Based on data from current vaccination studies in animal models, a human vaccine is achievable to intervene on the substantial incidence of infection.

Murine models of vaginal trichomonad infections

Trichomonas vaginalis and Tritrichomonas foetus cause common sexually transmitted infections in humans and cattle, respectively. Mouse models of trichomoniasis are important for pathogenic and therapeutic studies. Here, we compared murine genital infections with T. vaginalis and T. foetus. Persistent vaginal infection with T. foetus was established with 100 parasites but T. vaginalis infection required doses of 10(6), perhaps because of greater susceptibility to killing by mouse vaginal polymorphonuclear leukocytes. Infection with T. vaginalis persisted longest after combined treatment of mice with estrogen and dexamethasone, whereas infection was only short-lived when mice were given estrogen or dexamethasone alone, co-infected with Lactobacillus acidophilus, and/or pretreated with antibiotics. Infection rates were similar with metronidazole-resistant (MR) and metronidazole-sensitive (MS) T. vaginalis. High dose but not low dose metronidazole treatment controlled infection with MS better than MR T. vaginalis. These murine models will be valuable for investigating the pathogenesis and treatment of trichomoniasis.

Immunity to infections in the lower genital tract of bulls

The mucosa of the bovine prepuce has unique immunological characteristics critical to defense against sexually transmitted diseases. Tritrichomonas foetus and Campylobacter fetus subspecies venerealis persistently colonize the lower genital tract of bulls but usually do not cause either major clinical signs or inflammation. These microbes may be sexually transmitted to female cattle to cause reproductive failure. Although the male genital immune responses to T. foetus and C. fetus subspecies venerealis are inefficient in clearing infection, systemic immunization with T. foetus and C. fetus subspecies venerealis antigens does prevent or eliminate these infections with induction of IgG antibodies in genital secretions and serum.

Assessment of reproductive tract disease in cats at risk for Tritrichomonas foetus infection

OBJECTIVE

To determine whether Tritrichomonas foetus infection resides in reproductive tract tissues from cats housed for breeding and for which a high prevalence of colonic T foetus infection has been reported.

ANIMALS

61 purebred cats in 36 catteries undergoing elective ovariohysterectomy or castration and for which reproductive tract tissues, feces, and a reproductive history were obtained.

PROCEDURES

Reproductive tract tissues were examined for T foetus via light microscopy, immunohistochemical analysis, and PCR assay. History of reproductive tract disease was examined to detect statistical associations with identified or reported exposure to colonic T foetus infection.

RESULTS

15 of 61 (25%) cats and 22 of 33 (67%) catteries were identified with active or reported T foetus infection. Light microscopic, immunohistochemical, or molecular evidence of T foetus infection of the reproductive tract was not detected in any cats, including 15 cats with colonic T foetus infection, 29 cats residing in a cattery in which T foetus-infected cats were identified, and 8 cats for which gross or light microscopic evidence of reproductive tract disease was identified. There were no differences in total number of litters, number of litters per breeding, kitten mortality rate, or birth defects between cats or catteries infected with T foetus and those for which T foetus infection was not identified.

CONCLUSIONS AND CLINICAL RELEVANCE

No evidence of reproductive tract colonization by T foetus was detected in this study. Accordingly, it is unlikely that reproductive tract infection with T foetus plays an important role in overall disease transmission.

Bovine immunoglobulin E

The recognition of homocytotropic antibodies and their occurrence in response to parasite infection preceded the recognition of IgE as a distinct antibody isotype in the bovine species. Passive cutaneous anaphylaxis was an early reliable and antigen specific method to detect IgE in bovine serum. Yet studies on the role of IgE in bovine disease awaited the production of polyclonal and monoclonal antisera specific for the bovine epsilon chain. Applications of antigen specific ELISA and Western blot techniques have demonstrated IgE responses not only to parasite antigens, but also to viral and bacterial pathogens. The role of IgE in vaccine enhanced disease and in eliciting anaphylactic responses to some vaccines has been elucidated using these immunological assays.

Spermatozoa and seminal plasma induce a greater inflammatory response in the ovine uterus at oestrus than dioestrus

Leukocyte infiltration and increased synthesis of cytokines in response to insemination is considered to enhance reproductive success. The present study investigated the inflammatory response to whole semen, spermatozoa and seminal plasma, with and without the addition of antibiotics, in the ovine uterus at oestrus and dioestrus. Seminal plasma and spermatozoa both contributed to increased IL-8 secretion (P < 0.01) by endometrial epithelial cells and a concurrent infiltration by neutrophils (P < 0.01). Increased GM-CSF secretion (P < 0.01) occurred in response to whole semen and spermatozoa when antibiotics were not used. Macrophages and eosinophils increased (P < 0.05) in the endometrial stroma when antibiotics were not used, and fewer mast cells were detected in the deep endometrial stroma after treatments containing antibiotics (P < 0.05). Neutrophil and IL-8 responses to insemination were greater at oestrus (P < 0.01) than at dioestrus and the GM-CSF response followed a similar trend. Eosinophil numbers were increased at oestrus (P < 0.01) but minimally affected by insemination. More macrophages were located in the superficial endometrial stroma at oestrus. These results indicate that spermatozoa, seminal plasma and possibly bacteria contribute to the post-insemination inflammatory response, and that leukocytes, GM-CSF and IL-8 secretion in the ovine uterus are influenced by ovarian hormones.

A pregnant mouse model for bovine Tritrichomonas foetus infection

The economically important effects of Tritrichomonas foetus infection in cattle are abortion and infertility, yet there has not been an animal model to examine the parasite-host interactions during gestation. In this study, 5- and 7- to 8-week-old BALB/cAnNCr, BALB/cJ, and SCID/NCr mice on a BALB/c background were intravaginally infected with T. foetus. All BALB/cAnNCr and BALB/cJ mice, and 89% of SCID/NCr mice sustained infections for 13 weeks, if inoculated before 5 weeks of age. Infection rates were lower in all mouse strains inoculated at 7 weeks of age, although BALB/cAnNCr mice were significantly more susceptible than BALB/cJ or SCID/NCr mice. Vaginal bacterial flora did not account for the variation in mouse-strain susceptibility, although coagulase-negative staphylococci in vaginal flora were associated with failure of T. foetus to infect. As with infected cattle, T. foetus-specific vaginal immunoglobulin (Ig) G and IgA antibodies were elevated after infection. The number and viability of day-10 fetuses were reduced in mice infected at 5 weeks of age and bred 12 weeks after infection. Lesions in pregnant and nonpregnant infected mice, including suppurative and eosinophilic vaginitis; cervicitis; endometritis with distension of the uterine lumen; endometrial ulceration; and glandular ectasia, with neutrophils in the glandular lumen and loss of gland epithelium, were similar to those in cattle. The decidua and placenta were multifocally necrotic. Immunohistochemistry demonstrated trichomonads in vaginal folds and uterine glands, and adjacent to fetal tissues. In summary, experimentally infected BALB/cAnNCr mice showed many pathologic similarities to cattle and may serve as a model to study host-trichomonad interactions.

Selected diseases and conditions associated with bovine conceptus loss in the first trimester

The outcomes of insults to the bovine conceptus depend on the predilection of the insulting agent for the gravid reproductive tract, the virulence of the insult, and the developmental maturity/immune competence of the conceptus at the time of the insult. Agents that are lethal at one time during gestation may be harmless at another, or may have completely different effects (some not so harmless) at different gestational ages. This review discusses some of the known physical-mechanical, physiological, and infectious causes of first trimester bovine conceptus losses, including three infectious agents that have been the subject of recent studies for their potential to transmit disease via embryo transfer.

Neutrophils and inducible nitric-oxide synthase are critical for early resistance to the establishment of Tritrichomonas foetus infection

Tritrichomonas foetus is the cause of trichomoniasis in cattle. Severe infection is often associated with heavy neutrophil and macrophage accumulation, although it is not known how this response protects during early parasite colonization. The goal of this study was to examine the effects of an early host response upon initial T. foetus colonization within the murine reproductive tract. Mice depleted of neutrophils before T. foetus infection had a significantly higher parasite burden within the reproductive tract compared with mock-depleted control mice. Additionally, gp91(phox-/-)/ iNOS(-/-), and iNOS(-/-) mice had substantially larger parasite burdens than C57BL/6 control mice, whereas gp91l(Phox-/-) mice had similar parasite burden to C57BL/6 control mice. Interestingly, phorbol 12-myristate 13-acetate-stimulated neutrophils and macrophages isolated from all groups of mice were unable to kill T. foetus in vitro. However, macrophages isolated from gp91l(phox-/-) and C57BL/6 mice stimulated with interferon-gamma and lipopolysaccharide were able to kill T. foetus in vitro, whereas macrophages isolated from gp91(phox(-/-)/ iNOS(-/-) and iNOS(-/-) mice were unable to kill T. foetus, suggesting the ability of macrophages to produce reactive nitrogen species but not reactive oxygen species (ROS) is critical for parasite killing during early infection in vivo and in vitro. Additionally, neutrophils seem to control early dissemination of T. foetus throughout the reproductive tract, although production of ROS is not critical for this process.

The immune status of the bovine uterus during the peripartum period

The post-partum period in cattle is characterised by an increased risk of infection of the uterus, as the anatomical barriers are broached during parturition and remain open for several days. Infection of the uterus is largely influenced by the balance between bacterial contamination and the local and systemic immune status during pregnancy and around parturition. Infectious diseases are more prevalent during this period, because of an impaired immune status before and immediately after parturition. Neutrophils play a primary role in the defence of the uterus against infection. Influx of neutrophils into the uterus is thought to be mediated by chemoattractants, chemokines and adhesion molecules, such as beta2-integrin (complement receptor 3) and L-selectin (CD62L). Other cellular components activated in the uterus during this period include lymphocytes, eosinophils, mast cells and macrophages. The major classes of immunoglobulins (IgM, IgA and IgG), either by passive diffusion or local production, play an important protective role in the uterus by acting as opsonins to enhance phagocytosis, stimulating the complement pathways or blocking pathogens from adhering to mucosal surfaces. Endometrial cells express toll-like receptor 4 (TLR4), which recognises lipopolysaccharides of Escherichia coli and other Gram negative bacteria, the most common causes of bovine endometritis. Activation of TLR4 triggers the production of tumour necrosis factor alpha and other pro-inflammatory cytokines. The periparturient period is also characterised by an increased secretion of prostaglandin F(2alpha), which enhances uterine immune defences.

Leucocyte population changes in the reproductive tract of the ewe in response to insemination

Leucocyte changes after insemination may affect conceptus implantation, but information regarding leucocyte populations in the ruminant reproductive tract is limited. The present study investigated changes in leucocyte populations and distribution in the ovine reproductive tract following oestrus and insemination. Fifteen ewes were mated with a ram for 1 h and their reproductive tracts collected 3, 6, 18, 24 or 48 h later. Another 15 ewes were used as oestrus controls. Tissues were collected from 10 sites in each reproductive tract and stained with haematoxylin and eosin, Toluidine blue and immunohistochemically using a monoclonal CD68 antibody. Luminal mucus smears were collected from seven sites and stained with a modified Wright’s stain and immunohistochemically. Neutrophils, eosinophils, mast cells and macrophages were identified and quantified, and temporal changes in their distribution within tissues were examined. Neutrophils and macrophages increased significantly (P < 0.05) in posterior cervical and uterine tissues following insemination. In uterine tissues, neutrophils peaked at 6 h after insemination, whereas macrophages peaked at 18–24 h. Mast cells decreased and eosinophils remained constant. Neutrophils increased significantly (P < 0.05) in the cervical and uterine lumen following insemination. In conclusion, leucocyte population changes after insemination vary between different sites in the ovine reproductive tract and may contribute to pregnancy establishment.