Th1-type Response Research Articles

CCR2 signaling regulates anti-chlamydia T cell immune responses in the airway.

CCR2, a member of the G protein-coupled receptor (GPCR) superfamily, is widely expressed on monocytes, macrophages, activated T cells, and other cell types, and plays a critical role in coordinating the immune response to various infections. Here we demonstrate that CCR2 expression is significantly elevated during Chlamydia muridarum (C. muridarum) respiratory infection, and its absence leads to exacerbated susceptibility, as evidenced by significant weight loss, higher bacterial loads, severe lung pathology, and elevated levels of inflammatory cytokines (il-1β, tnfα, and il-6). The absence of ccr2 impairs both myeloid cell infiltration and T cell responses, which are crucial for effective immune defense. Specifically, ccr2 deficiency disrupts the differentiation and response of Th1 cells, which are the primary effector lineage responsible for clearing chlamydia through secretion of interferon-gamma (IFN-γ). As a result, there is a significant decrease in CD3+CD4+IFN-γ+ T cells in the lung and spleen, accompanied by reduced levels of IFN-γ protein and mRNA, as well as downregulated mRNA expression of Th1-promoting cytokines (il-12p35, il-12p40) and transcription factors (stat4, T-bet), which play crucial roles in Th1 differentiation. Moreover, ccr2 deficiency greatly diminishes STAT1 phosphorylation, a key regulator of IFN-γ secretion by Th1 cells. Meanwhile, we also observed a significant reduction in IFN-γ secretion by CD8+ T cells following ccr2 deficiency. Conversely, ccr2-/- mice exhibit an exaggerated Th2-type immune response, with elevated levels of Th2-promoting cytokines (IL-4), transcription factors (STAT6 and gata3), and il-5, which together lead to more severe lung tissue damage and increased susceptibility to infection. Furthermore, these mice show higher levels of IL-17 along with an enhanced Th17-type immune response, characterized by increased Th17-promoting cytokines TGFB, transcription factors stat3 and RORγt, and il-21, suggesting a compensatory mechanism that drives neutrophil infiltration to exacerbate lung inflammation. These findings underscore the pivotal role of CCR2, a chemokine receptor, in orchestrating the immune response to Chlamydia infection by facilitating Th1 cells differentiation while restraining Th2-type and Th17-type immune responses, thereby alleviating pulmonary inflammation.

Development and Evaluation of the Immunogenic Potential of an Unmodified Nucleoside mRNA Vaccine for Herpes Zoster.

Approved mRNA vaccines commonly use sequences modified with pseudouridine to enhance translation efficiency and mRNA stability. However, this modification can result in ribosomal frameshifts, reduced immunogenicity, and higher production costs. This study aimed to explore the potential of unmodified mRNA sequences for varicella-zoster virus (VZV) and evaluate whether codon optimization could overcome the limitations of pseudouridine modification. We utilized artificial intelligence (AI) to design several unmodified gE mRNA sequences for VZV, considering factors such as codon preference and secondary structure. The optimized mRNA sequences were assessed for protein expression levels in vitro and were subsequently used to develop a vaccine, named Vac07, encapsulated in a lipid nanoparticle (LNP) delivery system. The immunogenicity of Vac07 was evaluated in mice. Codon-optimized mRNA sequences showed significantly higher protein expression levels in vitro compared to wild-type (WT) sequences. Vaccination with Vac07 demonstrated immunogenicity in mice that was comparable to, or even superior to, the licensed Shingrix vaccine, characterized by a stronger Th1-biased antibody response and a slightly more robust Th1-type cellular response. Codon-optimized unmodified mRNA sequences may also represent a viable approach for mRNA vaccine development. These optimized sequences have the potential to lower production costs while possibly enhancing the immunogenicity of mRNA vaccines. Vac07, developed using this method, shows promise as a potentially more efficient and cost-effective mRNA vaccine candidate for VZV.

Molecular Mechanism of VSV-Vectored ASFV Vaccine Activating Immune Response in DCs.

The vesicular stomatitis virus (VSV)-vectored African swine fever virus (ASFV) vaccine can induce efficient immune response, but the potential mechanism remains unsolved. In order to investigate the efficacy of recombinant viruses (VSV-p35, VSV-p72)-mediated dendritic cells (DCs) maturation and the mechanism of inducing T-cell immune response, the functional effects of recombinant viruses on DC activation and target antigens presentation were explored in this study. The results showed that surface-marked molecules (CD80, CD86, CD40, and MHC-II) and secreted cytokines (IL-4, TNF-α, IFN-γ) were highly expressed in the recombinant virus-infected DCs. In addition, the co-culture results of recombinant virus-treated DCs with naive T cells showed that the Th1- and Th17-type responses were effectively activated. Taken together, the study indicated that the VSV-vectored ASFV vaccine activated the maturation of DCs and the Th1- and Th17-type immune response, which provided a theoretical basis for the development of novel ASF vaccines.

Absolute eosinophil count and expression analyses of cytokine genes in Haemonchus contortus resistant Malpura sheep: Role of TH1/TH2 cytokine dichotomy.

A strong Th2-type immune response against Haemonchus contortus infection in genetically resistant sheep provide immunity. The objective of present study was to correlate mean faecal egg counts (FECs), absolute eosinophil counts and Th1/Th2 gene expression in resistant (R) and susceptible (S) Malpura sheep. In spite of no anthelmintic treatment in R line, on majority of the months, mean FECs remained significantly (P<0.05) lower compared to S line where anthelmintic treatment was given in September every year. R sheep possess a smaller number of blood eosinophils in the majority of months as compared with S sheep and a positive correlation has been observed between absolute eosinophil counts and mean FEC. In the condition, when FEC remain similar in both the lines (R and S), significantly (P<0.05) up-regulated expression of IL-5 was observed in R sheep compared with S sheep however when FEC is hugely enhanced; IL-2, IL-6, IL-12 and IL-13 gene expression was significantly (P<0.05) up-regulated in R sheep as compared to S sheep which is dependent on season and parasite load.

Differential Immune Responses of Th1 Stimulatory Chimeric Antigens of Leishmania donovani in BALB/c Mice.

Visceral leishmaniasis (VL) is the third most severe infectious parasitic disease and is caused by the protozoan parasite Leishmania. To control the spread of the disease in endemic areas where the asymptomatic patients act as reservoirs as well as in nonendemic areas, an effective vaccine is indispensable. In this direction, we have developed three chimeric proteins by the combination of three already known Th1 stimulatory leishmanial antigens, i.e., enolase, aldolase, and triose phosphate isomerase (TPI). The newly developed chimeric proteins, i.e., enolase-aldolase, TPI-enolase, and aldolase-TPI along with BCG as an adjuvant were assessed and compared, examining humoral and cellular adaptive immune responses elicited in BALB/c mice. The three chimeric antigens exhibited differential immune responses shown by differences in Th1 and Th2 cytokine production in ex vivo stimulated splenocytes of immunized mice. It was observed that all three chimeric proteins are more immunogenic than their component proteins. However, while comparing the immune response of the three chimeric proteins, aldolase-TPI exhibited a better immunogenic (Th1-type) response, as evidenced by the highest IFN-γ production, a high IgG2a antibody isotype switching, a high % population of CD8+ and CD4+ T-cells, and a significantly high expression of iNOS2. Thus, the results suggest the potential of these chimeric antigens as strong immunogens that can be harnessed in vaccine development against VL.

Urine Proteomics in Schistosoma haematobium-induced Bladder Cancer

Schistosomiasis, or Bilharziasis, is a neglected tropical disease caused by Schistosoma parasites, which significantly impacts public health, particularly in Africa. Schistosoma haematobium, the primary species responsible for urogenital schistosomiasis (UGS), is associated with severe chronic conditions, including squamous cell carcinoma (SCC) of the bladder. This review explores the pathogenesis of UGS and its link to bladder cancer, highlighting the molecular mechanisms involved. The chronic inflammation caused by S. haematobium eggs leads to tissue damage, fibrosis, and granuloma formation, creating a pre-cancerous environment. Notably, the role of the p53 pathway in UGS-associated bladder cancer is emphasized, with mutations in the TP53 gene and overexpression of p53 contributing to genetic instability and malignant transformation. Additionally, the review discusses the presence of oestrogen-like metabolites in the urine of UGS patients, which are suspected to be involved in carcinogenesis through an oestrogen-DNA adduct-mediated pathway. Mass spectrometric analysis of urine samples from UGS patients revealed specific metabolites, including 8-oxodG, a marker of oxidative DNA damage, which could serve as potential biomarkers for early detection and progression of bladder cancer. The urine proteome profiling also identified distinct molecular pathways activated in UGS-related bladder cancer, including Th2-type immune responses, oxidative stress, and inflammation. These findings underscore the need for further research into the host-parasite interactions and the development of diagnostic biomarkers for schistosome-induced carcinogenesis. Understanding these mechanisms could enhance treatment strategies and improve prevention efforts for UGS-related bladder cancer, particularly in endemic regions where the disease burden remains high.

Stat3 Induces IL-10 and SR-A/CD204 Expression in Silica Nanoparticle-Triggered Pulmonary Fibrosis through Transactivation.

Inhalation of silica dust in the workplace has been addressed as a serious occupational pulmonary disease subsequently leading to inflammation and fibrosis. Enhanced expression of IL-10 significantly contributes to the disease etiology, along with an elevated Th2-type paradigm. Previously, we showed that the exaggerated Th2-type response was also associated with consistent upregulation of Stat3 in mouse airways stimulated with silica microparticles. However, a precise understanding of silicosis in light of the IL-10/Stat3 immune axis is required. We, therefore, aimed to determine the regulatory role of IL-10 in nanosized silica (nSiO2)-induced pulmonary fibrosis in association with Stat3. Herein, we report that amorphous nSiO2 could induce pulmonary fibrosis with consistent and concomitant upregulation of IL-10, Stat3, and SR-A/CD204. Following exogenous administration of siStat3 and rIL-10, the study further confirmed that Stat3 mediates the regulation of IL-10 and SR-A/CD204 and that IL-10 could regulate its own expression in an autoregulatory loop. The ChIP assay highlighted the localization of Stat3 over two putative binding sites in the IL-10 promoter region, which subsequently resulted in the overexpression of SR-A/CD204. Conclusively, Stat3-mediated transregulation of IL-10 through an autoregulatory loop in silicosis could offer novel molecular targets for therapeutic interventions.

Role of route of delivery on Chlamydia abortus vaccine-induced immune responses and genital tract immunity in mice.

We investigated if the efficacy of a Chlamydia abortus (Cab) subunit vaccine is influenced by route of administration. Thus, female CBA/J mice were immunized either by mucosal or systemic routes with Vibrio cholerae ghost (VCG)-based vaccine expressing T and B cell epitopes of Cab polymorphic membrane protein (Pmp) 18D, termed rVCG-Pmp18.3. Vaccine evaluation revealed that all routes of vaccine delivery induced a Th1-type antibody response after a prime boost or three-dose immunization regimen. Also, the intranasal and rectal mucosal and intramuscular systemic routes induced cross-reactive neutralizing antibodies against homologous and heterologous Cab strains. Irrespective of the route of immunization, the vaccine elicited a Th1-type cytokine response (IFN-γ/IL-4 >1) in immunized mice. Analysis of reduction in genital Cab burden as an index of protection showed that immunization induced substantial degrees of protection against infection, irrespective of route of delivery with the intranasal and rectal mucosal routes showing superior levels of protection 12 days postchallenge. Furthermore, there was correlation between the humoral and cellular immune response and protection was associated with the Cab-specific serum IgG antibody avidity and IFN-γ. Thus, while route of administration impacts vaccine efficacy, the rVCG-Pmp18.3-induced protective immunity against Cab respiratory infection can be accomplished by both mucosal and systemic immunization.

Preclinical evaluation of immunogenicity and protective efficacy of a recombinant chimeric protein vaccine against visceral leishmaniasis.

Visceral leishmaniasis (VL) is a tropical disease that can be fatal if acute and untreated. Diagnosis is difficult, the treatment is toxic and prophylactic vaccines do not exist. Leishmania parasites express hundreds of proteins and several of them are relevant for the host's immune system. In this context, in the present study, 10 specific T-cell epitopes from 5 parasite proteins, which were identified by antibodies in VL patients’ sera, were selected and used to construct a gene codifying the new chimeric protein called rCHI. The rCHI vaccine was developed and thoroughly evaluated for its potential effectiveness against Leishmania infantum infection. We used monophosphoryl lipid A (MPLA) and polymeric micelles (Mic) as adjuvant and/or delivery system. The results demonstrated that both rCHI/MPLA and rCHI/Mic significantly stimulate an antileishmanial Th1-type cellular response, with higher production of IFN-γ, TNF-α, IL-12 and nitrite in vaccinated animals, and this response was sustained after challenge. In addition, these mice significantly reduced the parasitism in internal organs and increased the production of IgG2a isotype antibodies. In vivo and in vitro toxicity showed that rCHI is safe for the mammalians, and the recombinant protein also induced in vitro lymphoproliferative response and production of Th1-type cytokines by human cells, which were collected from healthy subjects and treated VL patients. These data suggest rCHI plus MPLA or micelles could be considered as a vaccine candidate against VL.

CD163 Expression in Chronic Intervillositis of Unknown Etiology and SARS-CoV-2 Placentitis.

Chronic intervillositis of unknown etiology (CIUE) is an aberrant maternal inflammatory infiltrate comprised primarily of macrophages that collect in the intervillus space and is associated with poor outcomes including recurrent pregnancy loss. An abnormal maternal Th1-type response to pregnancy may be the basis for pathogenesis of CIUE but macrophage in the maternal infiltrate of CIUE have been reported to have an anti-inflammatory M2 phenotype characterized by increased expression of CD163. This study assesses expression of CD163 in CIUE and SARS-CoV-2 placentitis, which has a similar histopathological presentation, using an automated approach to minimize observer-related variability. The data show that the maternal inflammatory infiltrate of CIUE contains a blended population of high and low CD163 expressing macrophage with a prominent bias towards an anti-inflammatory M2 phenotype when compared to normal control tissue. A similar pattern is seen in SARS-CoV-2 placentitis, suggesting pathophysiologic similarity with CIUE, although SARS-CoV-2 also appears to promote decreased CD163 expression in Hofbauer cells, which is not seen in CIUE.

The immune responses elicited by six recombinant antigens of Mycoplasma hyopneumoniae in mice

Mycoplasma hyopneumoniae (M. hyopneumoniae) is the causative agent of swine enzootic pneumonia, resulting in substantial economic losses in global pig farming. Although vaccination is the primary strategy for controlling M. hyopneumoniae infection, current vaccines fall short in preventing transmission of this pathogen or protecting the body from secondary infection. This study aimed to assess the immunogenicity of six recombinant antigens (P97R1, P46, GAPDH, PdhA, DnaK, and EF-Tu) of M. hyopneumoniae through intramuscular immunization in mice. The results showed that the six antigens elicited high levels of serum IgG. Among them, P97R1, P46, PdhA, and DnaK stimulated robust antigen-specific IgA mucosal immune responses. CCK-8 assays revealed that both P97R1 and DnaK significantly increased the proliferation of mononuclear cells from spleen and lung, and DnaK also promoted the proliferation of blood mononuclear cells. Additionally, PdhA induced Th17-type immune response with a high level of IL-17 level in serum. Flow cytometry analysis indicated that P97R1 and PdhA increased the ratio of CD8+/CD4+ T lymphocyte, favoring cytotoxic T lymphocyte (CTL) immune responses. Notably, P97R1 immunization significantly decreased the percentages of CD4+ T cells while increased the percentages of CD8+ T cells. The present findings demonstrate that the candidate antigens P97R1, PdhA, and DnaK of M. hyopneumoniae induce specific humoral and mucosal immunity; P97R1 and DnaK also stimulated intense cellular immunity, and PdhA induced CTL and Th17-type immune responses. In conclusion, P97R1, PdhA, and DnaK emerge as potential candidate antigens for the future development of a more effective subunit vaccine against M. hyopneumoniae.

Neutrophil-activating protein in Bacillus spores inhibits casein allergy via TLR2 signaling.

Milk allergy commonly occurs in children, mainly caused by bovine-derived casein (CAS) protein. Neutrophil-activating protein (NAP) of Helicobacter pylori plays an immunomodulatory role with potential to suppress Th2-type immune responses. Bacillus subtilis (B. subtilis) spores are commonly used as oral vectors for drug delivery. To investigate whether recombinantly expressed NAP on B. subtilis spores could be an effective treatment for CAS allergy in mouse. After CAS sensitization, mice were orally administered B. subtilis spores expressing recombinant NAP for 6 weeks. Allergic symptoms and parameters were evaluated after CAS challenge oral gavage, including allergic inflammation, splenic cytokines, and serum-specific antibodies. Protein levels of Toll-like receptor 2 (TLR2) and c-JUN in the jejunum tissue were measured by western blot. Bone marrow-derived macrophages (BMDMs) were stimulated with inactivated NAP spores to measure the influence on cytokine profiles in vitro. NAP recombinant spore treatment significantly reduced allergic symptoms and intestinal inflammation. Interleukin-12 and interferon-gamma levels increased, whereas serum CAS-specific IgG1 and IgE levels decreased. TLR2 and c-JUN expression levels were elevated in the jejunal tissue. Inactivated NAP spores polarized BMDMs to the M1 phenotype and enhanced cytokine expression, which were inhibited by a TLR2 neutralizing antibody. NAP offers a new strategy in the treatment of CAS allergy by inhibiting the Th2 response, while eliciting macrophages to promote Th1 immune responses.

Bioinformatics Analysis and Immunogenicity Assessment of the Novel Multi-Stage DNA Vaccine W541 Against Mycobacterium Tuberculosis.

Vaccination is one of the effective measures to prevent latent tuberculosis infection (LTBI) from developing into active tuberculosis (TB). Applying bioinformatics methods to pre-evaluate the biological characteristics and immunogenicity of vaccines can improve the efficiency of vaccine development. To evaluate the immunogenicity of TB vaccine W541 and to explore the application of bioinformatics technology in TB vaccine research. This study concatenated the immunodominant sequences of Ag85A, Ag85B, Rv3407, and Rv1733c to construct the W541 DNA vaccine. Then, bioinformatics methods were used to analyze the physicochemical properties, antigenicity, allergenicity, toxicity, and population coverage of the vaccine, to identify its epitopes, and to perform molecular docking with MHC alleles and Toll-like receptor 4 (TLR4) of the host. Finally, the immunogenicity of the vaccine was evaluated in animal experiments. The W541 vaccine protein is a soluble cytoplasmic protein with a half-life of 1.1 h in vivo and an instability index of 45.37. It has good antigenicity and wide population coverage without allergenicity and toxicity. It contains 138 HTL epitopes, 73 CTL epitopes, 8 linear and 14 discontinuous B cell epitopes, and has a strong affinity for TLR4. Immune simulations have shown that it can effectively stimulate innate and adaptive immune responses. Animal experiments confirmed that the W541 DNA vaccine could effectively activate Th1- and Th17-type immune responses, producing high levels of IFN-γ and IL-17A, but could not significantly increase antibody levels. The W541 DNA vaccine can induce strong cellular immune responses. However, further optimization of the vaccine design is needed to make the expressed protein more stable in vivo. Bioinformatics analysis could reveal the physicochemical and immunological information of vaccines, which is critical for guiding vaccine design and development.

Chinese yam polysaccharide-loaded aluminium hydroxide nanoparticles used as vaccine adjuvant to induce potent humoral and cellular immune responses

Due to their safety and efficacy, aluminium salts (Alum) are considered the most important adjuvants in human vaccines. However, Alum adjuvants are unable to elicit a cellular immune response, which is vital for the prevention of various chronic infectious diseases and cancers. Herein, we isolated and purified a water-soluble polysaccharide from Chinese yam, named CYP, which was primarily composed of →4)-α-D-Glcp-(1→, →4,6)-α-D-Glcp-(1→, and α-D-Glcp-(1→. Meanwhile, we prepared aluminium hydroxide nanoparticles (Al NPs) with a nanometer-scale size and thin stick-like shape. Being an immunostimulant, the CYP was then loaded onto the Al NPs to obtain a novel adjuvant delivery system (CYP-Al NPs) that enhances the immunostimulatory activity of CYP. Our findings showed that the CYP-Al NPs facilitated macrophages activation and promoted the antigen uptake by macrophages. The in vivo experiment showed that the CYP-Al NPs, as the adjuvant to ovalbumin, promoted the activation of dendritic cells and germinal center B cells in draining lymph nodes, induced a durable and strong antibody response, especially the Th1-type IgG2a antibody response, and improved the cytotoxic T lymphocytes response. These results demonstrated that the CYP-Al NPs could generate robust humoral and cellular responses, and has the great potential to serve as an adjuvant delivery system.

Synthetic small interfering RNAs selectively suppress the expression of proinflammatory cytokine genes (IL-25 and TSLP) in experiments in vitro

Allergic rhinitis (AR) is an inflammatory disease of the upper respiratory tract (nasal mucosa). AR affects up to 40% of the world’s population; in the Russian Federation, the incidence is 18% to 30%, depending on the region. Despite the fact that AR is not a severe pathology, it causes significant economic burden. Another threat associated with this disease is that in 40% of cases, patients with AR eventually develop a more severe disabling pathology – AD. Widespread prevalence and significant economic disadvantages caused by AR determine the importance of developing new ways of prevention and control of this disease, as the existing methods of therapy are insufficient. However, the search for new ways of therapy is impossible without a detailed investigation of the molecular mechanisms of AR pathogenesis. For a long time it was considered that this allergic inflammation is formed by Th2-dependent mechanism with involvement of Th2-lymphocytes, B-cells and eosinophils and pro-inflammatory cytokines: IL-4, IL-5 and IL-13. However, experimental evidence has now accumulated on the role of epithelial cells of the respiratory tract and the proinflammatory cytokines they secrete (IL-25, IL-33 and TSLP) in the pathogenesis of AR and AD. IL-25 has been shown to induce the production of IL-4, IL-5 and IL-13, directing a Th2-type immune response. At the same time, mice with inactivated IL-25 developed barely any Th2-immune response. Inactivation of IL-33 significantly reduces inflammation (mediated by eosinophils) of the respiratory tract. Mice knockout for the cytokine receptor TSLP did not develop nasal hyperreactivity in response to allergen, but the level of nasal mucosal inflammation remained high. Currently, work is actively progressing on the development of new drugs capable of specifically blocking the activity of the listed cytokines; first of all, drugs based on neutralizing monoclonal antibodies. However, there are other technologies that can be used to regulate the activity of genes, such as the technology based on the RNA interference. It can be used to suppress the expression of any gene with a known nucleotide sequence, including genes encoding pro-inflammatory cytokines.Considering the above, the aim of this work was to design synthetic miRNA molecules and study their ability to specifically block the expression of genes encoding proinflammatory cytokines IL-25 and TSLP in experiments in vitro.

Rational optimization of glycoprotein E (gE)-encoding mRNA for improved Varicella-zoster virus mRNA vaccine development

ABSTRACT mRNA platform holds promise for next-generation Varicella-zoster Virus (VZV) vaccine development due to its high potency at inducing strong T-cell response. Built upon the design of our 1st-generation VZV mRNA vaccine that encodes for full-length gE antigen, in this study we reported on a novel combinatorial strategy to further optimize the gE-encoding mRNA sequence through signal peptide replacement, C-terminal modification, and insertion of mRNA-stabilizing motif, which collectively contributed to significantly improved vaccine immunogenicity. In adult mice, aged mice, and immunocompromised mice, this optimized VZV mRNA vaccine showed strong superiority in multiple aspects including the induction of gE-specific antibodies, specific memory B-cell response, as well as Th1-type T-cell response.

Humans seropositive for Trypanosoma cruzi co-infected with intestinal helminths have higher infectiousness, parasitaemia and Th2-type response in the Argentine Chaco

BackgroundThe Gran Chaco ecoregion is a well-known hotspot of several neglected tropical diseases (NTDs) including Chagas disease, soil-transmitted helminthiasis and multiparasitic infections. Interspecific interactions between parasite species can modify host susceptibility, pathogenesis and transmissibility through immunomodulation. Our objective was to test the association between human co-infection with intestinal parasites and host parasitaemia, infectiousness to the vector and immunological profiles in Trypanosoma cruzi-seropositive individuals residing in an endemic region of the Argentine Chaco.MethodsWe conducted a cross-sectional serological survey for T. cruzi infection along with an intestinal parasite survey in two adjacent rural villages. Each participant was tested for T. cruzi and Strongyloides stercoralis infection by serodiagnosis, and by coprological tests for intestinal parasite detection. Trypanosoma cruzi bloodstream parasite load was determined by quantitative PCR (qPCR), host infectiousness by artificial xenodiagnosis and serum human cytokine levels by flow cytometry.ResultsThe seroprevalence for T. cruzi was 16.1% and for S. stercoralis 11.5% (n = 87). We found 25.3% of patients with Enterobius vermicularis. The most frequent protozoan parasites were Blastocystis spp. (39.1%), Giardia lamblia (6.9%) and Cryptosporidium spp. (3.4%). Multiparasitism occurred in 36.8% of the examined patients. Co-infection ranged from 6.9% to 8.1% for T. cruzi-seropositive humans simultaneously infected with at least one protozoan or helminth species, respectively. The relative odds of being positive by qPCR or xenodiagnosis (i.e. infectious) of 28 T. cruzi-seropositive patients was eight times higher in people co-infected with at least one helminth species than in patients with no such co-infection. Trypanosoma cruzi parasite load and host infectiousness were positively associated with helminth co-infection in a multiple regression analysis. Interferon-gamma (IFN-γ) response, measured in relation to interleukin (IL)-4 among humans infected with T. cruzi only, was 1.5-fold higher than for T. cruzi-seropositive patients co-infected with helminths. The median concentration of IL-4 was significantly higher in T. cruzi-seropositive patients with a positive qPCR test than in qPCR-negative patients.ConclusionsOur results show a high level of multiparasitism and suggest that co-infection with intestinal helminths increased T. cruzi parasitaemia and upregulated the Th2-type response in the study patients.Graphical

Long-Term Oral Administration of Hyperimmune Egg-Based IgY-Rich Formulations Induces Mucosal Immune Response and Systemic Increases of Cytokines Involved in Th2- and Th17-Type Immune Responses in C57BL/6 Mice.

Three hyperimmune egg-based formulations rich in immunoglobulin Y (IgY) were orally administered (daily, for up to 90 days) to C57BL/6 mice that were not microbially challenged. The serum levels of 32 cytokines were quantified every 30 days. Histopathology, hematology, and serum biochemistry investigations were also performed. As a sign of increased immune activity, lymphohistiocytic infiltrates were detected in the digestive tract and the liver after 30, 60, and 90 days of treatment. These infiltrates were also present in the lungs after 30 and 60 days, but not at 90 days. Blood analysis indicated systemic inflammation after 30 days of treatment: increases in pro-inflammatory cytokines, glycemia, total serum proteins, ALT, and ALP. After 60 and 90 days of treatment, the analyzed blood parameters showed mixed signs of both increased and decreased inflammation. The increased cytokines, which varied with formulation and time of exposure, indicated a combination of mostly Th17- and Th2-type immune responses. As the mice were healthy and housed in standardized sanitary conditions, and were not microbially challenged, the data were consistent with an interaction of IgY with the gut-associated lymphoid tissue as the main mechanism of action. This interaction generated a local immune response, which subsequently induced a systemic response.

Escherichia coli LTB26 mutant enhances immune responses to rotavirus antigen VP8 in a mouse model

Adjuvant is a major supplementary component of vaccines to boost adaptive immune responses. To select an efficient adjuvant from the heat-labile toxin B subunit (LTB) of E. coli, four LTB mutants (numbered LTB26, LTB34, LTB57, and LTB85) were generated by multi-amino acid random replacement. Mice have been intranasally vaccinated with human rotavirus VP8 admixed. Among the four mutants, enzyme-linked immunosorbent assay (ELISA) revealed that LTB26 had enhanced mucosal immune adjuvanticity compared to LTB, showing significantly enhanced immune responses in both serum IgG and mucosal sIgA levels. The 3D modeling analysis suggested that the enhanced immune adjuvanticity of LTB26 might be due to the change of the first LTB α-helix to a β-sheet. The molecular mechanism was studied using transcriptomic and flow cytometric (FCM) analysis. The transcriptomic data demonstrated that LTB26 enhanced immune response by enhancing B cell receptor (BCR) and major histocompatibility complex (MHC) II+-related pathways. Furthermore, LTB26 promoted Th1 and Th2-type immune responses which were confirmed by detecting IFN-γ and IL-4 expression levels. Immunohistochemical analysis demonstrated that LTB26 enhanced both Th1 and Th2 type immunity. Therefore, LTB26 was a potent mucosal immune adjuvant meeting the requirement for use in human clinics in the future.

Evaluation of vaccine candidates against Rhodococcus equi in BALB/c mice infection model: cellular and humoral immune responses

Rhodococcus equi (R. equi) is a zoonotic opportunistic pathogen that mainly causes fatal lung and extrapulmonary abscesses in foals and immunocompromised individuals. To date, no commercial vaccine against R. equi exists. We previously screened all potential vaccine candidates from the complete genome of R. equi using a reverse vaccinology approach. Five of these candidates, namely ABC transporter substrate-binding protein (ABC transporter), penicillin-binding protein 2 (PBD2), NlpC/P60 family protein (NlpC/P60), esterase family protein (Esterase), and M23 family metallopeptidase (M23) were selected for the evaluation of immunogenicity and immunoprotective effects in BALB/c mice model challenged with R. equi. The results showed that all five vaccine candidate-immunized mice experienced a significant increase in spleen antigen-specific IFN-γ- and TNF-α-positive CD4 + and CD8 + T lymphocytes and generated robust Th1- and Th2-type immune responses and antibody responses. Two weeks after the R. equi challenge, immunization with the five vaccine candidates reduced the bacterial load in the lungs and improved the pathological damage to the lungs and livers compared with those in the control group. NlpC/P60, Esterase, and M23 were more effective than the ABC transporter and PBD2 in inducing protective immunity against R. equi challenge in mice. In addition, these vaccine candidates have the potential to induce T lymphocyte memory immune responses in mice. In summary, these antigens are effective candidates for the development of protective vaccines against R. equi. The R. equi antigen library has been expanded and provides new ideas for the development of multivalent vaccines.