Immune Response of BALB/c Mice toward Putative Calcium Transporter Recombinant Protein of Trichomonas vaginalis

Activation of murine macrophages by membrane proteins from Tritrichomonas foetus grown on iron- and calcium-rich conditions

Tritrichomonas foetus is a protozoan parasite that causes a venereal disease in cattle limiting reproduction by abortions and sterility. The immune response against this parasite is poorly understood. Since the iron and calcium ions are important regulators of the microenvironment of the urogenital tract in cattle, we decided to evaluate the role of these divalent cations on the antigenicity of membrane proteins of T. foetus on macrophage activation as one of the first inflammatory responses towards this pathogen. Colorimetric methods and ELISA were used to detect the nitric oxide and oxygen peroxide production and expression of cytokines in culture supernatant from macrophage incubated with membrane proteins from T. foetus cultured in iron- and calcium-rich conditions. qRT-PCR assays were used to evaluate the transcript expression of genes involved in the inflammatory response on the macrophages. The membrane proteins used for in vitro stimulation caused the up-regulation of the iNOS and NOX-2 genes as well as the generation of NO and H2 O2 in murine macrophages on a dependent way of the metal concentrations. Additionally, after stimulation, macrophages showed a considerable rise in pro-inflammatory cytokines and a downregulation of anti-inflammatory cytokines, as well as up-regulation in the transcription of the TLR4 and MyD88 genes. These data suggest that membrane proteins of T. foetus induced by iron and calcium can activate an inflammatory specific macrophage response via TLR4/MyD88 signalling pathway.

Exposure of Tritrichomonas foetus to sublethal doses of metronidazole induces a specific proinflammatory response in murine macrophages

Tritrichomonas foetus is a flagellated parasite that primarily infects the reproductive tissues of livestock, causing bovine trichomoniasis. The cytoplasmic membrane of T. foetus contains various compounds that contribute to adherence, colonization, and pathogenicity. Metronidazole (MTZ) is the main treatment for trichomoniasis, but the emergence of drug-resistant strains is a concern due to improper use and dosing. T. foetus infection induces inflammation, and macrophages are key players in the immune response. However, our understanding of the host's immune response to T. foetus is limited, and the specific mechanisms underlying these responses are not well understood. This study aimed to investigate the impact of T. foetus surface proteins from trophozoites cultured under different sublethal MTZ conditions (MTZ-treated T. foetus MPs) on macrophage activation. By analyzing cytokine levels and gene expression in murine macrophages, we demonstrated that MTZ-treated T. foetus MPs induce a specific proinflammatory response. MTZ-treated T. foetus MPs-exposed macrophages exhibited a higher NO and H2 O2 production and overexpression of iNOS and NOX-2 genes in comparison to untreated T. foetus. Additionally, MTZ-treated T. foetus MPs triggered a significant induction of the proinflammatory cytokines IL-1β, IL-6, TNF-α, and IFN-γ, as well as the overexpression of the TLR4, MyD88, and NF-κB genes on murine macrophages. The study aimed to unravel the immunological response and potential proinflammatory pathways involved in T. foetus infection and MTZ stress. Understanding the immune responses and mechanisms through which T. foetus surface proteins activate macrophages can contribute to the development of new therapeutic strategies for controlling bovine trichomoniasis.

Infinity war: Trichomonas vaginalis and interactions with host immune response

Trichomonas vaginalis is the pathological agent of human trichomoniasis. The incidence is 156 million cases worldwide. Due to the increasing resistance of isolates to approved drugs and clinical complications that include increased risk in the acquisition and transmission of HIV, cervical and prostate cancer, and adverse outcomes during pregnancy, increasing our understanding of the pathogen's interaction with the host immune response is essential. Production of cytokines and cells of innate immunity: Neutrophils and macrophages are the main cells involved in the fight against the parasite, while IL-8, IL-6 and TNF-α are the most produced cytokines in response to this infection. Clinical complications: T. vaginalis increases the acquisition of HIV, stimulates the invasiveness and growth of prostate cells, and generates an inflammatory environment that may lead to preterm birth. Endosymbiosis: Mycoplasma hominis increased cytotoxicity, growth, and survival rate of the parasite. Purinergic signaling: NTPD-ases and ecto-5'-nucleotidase helps in parasite survival by modulating the nucleotides levels in the microenvironment. Antibodies: IgG was detected in serum samples of rodents infected with isolates from symptomatic patients as well as patients with symptoms. However, antibody production does not protect against a reinfection. Vaccine candidate targets: The transient receptor potential- like channel of T. vaginalis (TvTRPV), cysteine peptidase, and α-actinin are currently cited as candidate targets for vaccine development. In this context, the understanding of mechanisms involved in the host-T. vaginalis interaction that elicit the immune response may contribute to the development of new targets to combat trichomoniasis.

Local cytokine/chemokine profiles in BALB/c and C57BL/6 mice in response to T. vaginalis infection

Trichomonas vaginalis is the causative agent of Trichomoniasis (a sexually transmitted infection). Recent reports have shown that stimulation of cellular immunity can reduce trichomoniasis infection. Animal studies are essential to understanding the pathogenesis of infection and developing new potential drugs and vaccines to treat the infection. Therefore, we have tried to understand the pathogenesis of T. vaginalis infection by investigating the differences in the expression of chemokine/cytokine levels in vaginal and cervical tissues of BALB/c and C57BL/6 mice. Different pathological symptoms, like desquamation, neutrophil infiltration, and hemorrhage, were recorded in BALB/c and C57BL/6 in response to T. vaginalis infection. Vaginal and cervical tissues of BALB/c showed these symptoms on 2nd dpi, which became severe on 7th dpi and turned to mild or normal till 14th dpi compared to C57BL/6 strain. Immunohistochemistry in the vagina and cervical tissues of BALB/c and C57BL/6 mice was done to assess cytokines at different time intervals post-infection. Significant expression of Interleukin-1β (IL-1β) (a pro-inflammatory cytokine) was found in BALB/c compared to the C57BL/6 mice, on 7th dpi and 2nd dpi in vaginal and cervical tissues, respectively. Higher expression of MIP-2 (neutrophil chemoattractant) was observed in the vaginal tissues of BALB/c mice on 7th dpi compared to the C57BL/6 group. In addition, higher expression of TGF-β (immune-suppressor) was observed on 7th dpi in the vaginal tissue of BALB/c mice. The present study demonstrates that more pathological signs of T. vaginalis infection developed in BALB/c mice than C57BL/6 mice. Also, significant levels of IL-1β and MIP-2 were measured in BALB/c mice in response to T. vaginalis compared to C57BL/6.

Clinical Manifestation and Epidemiological Finding of Trichomonas vaginalis Infection in Unusual Areas of Body in Neonates: A Systematic Review

BACKGROUND

This study intends to increase awareness on the clinical and laboratory diagnosis as well as health care of newborns with trichomoniasis from infected mothers, to introduce this organism as a respiratory pathogen with lower prevalence in other areas, and to outline its manifestations and symptoms.

METHODS

All case report articles in English language regarding the presence of T. vaginalisin unusual areas among infants, which were available in Scopus, PubMed, Science Direct, Google scholar, and Web of Science published between 1980 and 2021 were searched and reported by two independent researchers. Titles and abstracts of all articles were reviewed for initial screening.

RESULTS

After searching the articles and evaluating their quality, 9 full text articles were selected. All reported cases were from 8 different cities (4 countries) in the world. In most cases, the parasite was in the respiratory tract, but it was also reported in the brain and urogenital tract. The most common clinical symptom was respiratory distress.

CONCLUSION

Although the possibility of trichomoniasis infection in unusual areas such as genitals is low, according to the reports collected from around the world, this parasite can also be present outside the genitals. Perhaps, reviewing trichomoniasis along with other diagnoses in these cases may lead to early diagnosis and treatment of the affected neonates.

The molecular characterization and immune protection of adhesion protein 65 (AP65) of Trichomonas vaginalis

BACKGROUND

Adherence to the surface of the host cell is the precondition for T. vaginalis parasitism and pathogenicity, causing urogenital infection. The AP65 of T. vaginalis (TvAP65) involves in the process of adhesion. So, the present study was aimed at investigating the molecular characterization and vaccine candidacy of TvAP65 for protecting the host from the onset of Trichomoniasis.

METHODS

The open reading frame (ORF) of TvAP65 was amplified and then inserted into pET-32a (+) to clone recombinant TvAP65 (rTvAP65). The immunoblotting determined the immunogenicity and molecular size of TvAP65, while immunofluorescence staining visualized and the precise localization of TvAP65 in T. vaginalis trophozoites. Animal challenge and enzyme-linked immunosorbent assay (ELISA) test were used to evaluate the immunoprotection and the types of the immune response of TvAP65.

RESULTS

By the sequence analysis, TvAP65 encoded a 63.13 kDa protein that consisted 567 amino acid residues with a high antigenic index. The western blotting revealed that rTvAP65 and native TvAP65 could interact with the antibodies in the rat serums post hoc rTvAP65 immunization and the serums from the mice that were experimentally infected with T. vaginalis, respectively. Immunofluorescence stained TvAP65 on the surface of T. vaginalis trophozoites. Moreover, following emulsification with Freund's adjuvant, rTvAP65 was subsequently administered to BALB/c mice three times at 0, 2, and 4 weeks and the results from this animal challenge experiments showed significant increases in immunoglobulins of IgG2a, IgG1, and IgG, and cytokine of IFN-γ, and IL-2, and 10. Lastly, rTvAP65 vaccinated animals had a prolonged survival time (26.80 ± 4.05) after challenged by T. vaginalis.

CONCLUSIONS

TvAP65 mediated the adhesion of T. vaginalis to the host epithelia for the pathogenesis of the parasite and can be considered as a candidate protein for designing a functional vaccine that induces cell-mediated and humoral immunity against the T. vaginalis infection.

The Molecular Characterization and Immunity Identification of Trichomonas vaginalis Adhesion Protein 33 (AP33)

Trichomoniasis is caused by Trichomonas vaginalis (T. vaginalis), which is a widespread and serious sexually transmitted pathogen in humans. The procedure of T. vaginalis adherence to the host cell is the precondition for T. vaginalis parasitism and pathogenicity. The AP33 adhesin of T. vaginalis (TvAP33) plays a key role in the process of adhesion. In this study, the specific primers for polymerase chain reaction (PCR) were designed based on the sequence of TvAP33 (GenBank Accession No. U87098.1) to amplify the open reading frame (ORF), and the ORF was inserted into pET-32a (+) to produce recombinant TvAP33 (rTvAP33). The sequence analysis indicated that the TvAP33 gene encoded a protein of 309 amino acids with 32.53 kDa, and the protein was predicted to have a high antigen index. Western blotting assay showed rTvAP33 was successfully recognized by the sera of mice experimentally infected with T. vaginalis, while native TvAP33 in the somatic extract of T. vaginalis trophozoite was as well detected by sera from rats immunized with the rTvAP33. Immunofluorescence analysis using an antibody against rTvAP33 demonstrated that the protein was expressed and located on the surface of T. vaginalis trophozoites. The recombinant protein was emulsified in Freund's adjuvant and used to immunize BALB/C mice three times at days 0, 14, and 28. The result of animal challenge experiments revealed the levels of IgG, IgG1, and IgG2a, and IL-4, IL-10, and IL17 among rTvAP33 vaccinated animals were integrally increased. Moreover, the rTvAP33 vaccinated animals were apparently prolonged survival time (26.45 ± 4.10) after challenge infection with this parasite. All these results indicated that TvAP33 could be used as vaccine candidate antigen to induce cell-mediated and humoral immunity.