Maternal schistosomiasis alters costimulatory molecules expression in antigen-presenting cells from adult offspring mice

Fetomaternal immune cross talk modifies T-cell priming through sustained changes to DC function

BACKGROUND

Prenatal exposure to infections can modify immune development. These environmental disturbances during early life potentially alter the incidence of inflammatory disorders as well as priming of immune responses. Infection with the helminth Schistosoma mansoni is widely studied for its ability to alter immune responsiveness and is associated with variations in coinfection, allergy, and vaccine efficacy in endemic populations.

OBJECTIVE

Exposure to maternal schistosomiasis during early life, even without transmission of infection, can result in priming effects on offspring immune responses to bystander antigenic challenges as related to allergic responsiveness and vaccination, with this article seeking to further clarify the effects and underlying immunologic imprinting.

METHODS

Here, we have combined a model of chronic maternal schistosomiasis infection with a thorough analysis of subsequent offspring immune responses to allergy and vaccination models, including viral challenge and steady-state changes to immune cell compartments.

RESULTS

We have demonstrated that maternal schistosomiasis alters CD4+ responses during allergic sensitization and challenge in a skewed IL-4/B-cell-dominant response to antigenic challenge associated with limited inflammatory response. Beyond that, we have uncovered previously unidentified alterations to CD8+ T-cell responses during immunization that are dependent on vaccine formulation and have functional impact on the efficacy of vaccination against viral infection in a murine hepatitis B virus model.

CONCLUSION

In addition to steady-state modifications to CD4+ T-cell polarization and B-cell priming, we have traced these modified CD8+ responses to an altered dendritic cell phenotype sustained into adulthood, providing evidence for complex priming effects imparted by infection via fetomaternal cross talk.

Influence of schistosomiasis on host vaccine responses

Schistosomiasis is a debilitating helminthiasis which commonly establishes as a chronic infection in people from endemic areas. As a potent modulator of the host immune response, the Schistosoma parasite and its associated products can directly interfere with its host's ability to mount adequate immune responses to unrelated antigens. As a result, increased attention is gathering on studies assessing the influence of helminths, particularly the causal agent of schistosomiasis, on host responsiveness to vaccines. However, to date, no consensus has been drawn regarding the influence of schistosomiasis on host vaccine responses. Here, we review available evidence on the influence of transgenerational and direct Schistosoma parasite exposure on host immune responses to unrelated vaccines. In addition, we evaluate the potential of praziquantel (PZQ) treatment in restoring schistosomiasis-impacted vaccine responses.

Suckling by Schistosoma mansoni-infected mothers restored IgG2a and TGF-β production, but not IL-6 and delayed-type hypersensitivity in IL-12/IL-23-deficient mice

INTRODUCTION

Suckling by schistosomotic mice improves anti-ovalbumin (OA) antibody production, while delayed-type hypersensitivity (DTH) remains unaffected. This property of milk from schistosomotic mice was investigated in IL-12/IL-23-deficient mice (IL-12p40KO).

METHODS

We compared anti-OA DTH, IgG2a and cytokines in wild-type and IL-12p40KO mice suckled by infected (SIM) or non-infected (CONTROL) mothers.

RESULTS

SIM mice showed similar intensity and eosinophils in the DTH, which was abolished in IL-12p40KO and IL-12p40KO-SIM mice. In IL-12p40KO-SIM, IgG2a and TGF-β levels were higher, but IL-6 levels were lower.

CONCLUSIONS

Milk from schistosomotic mothers may evoke IgG2a without eliciting DTH in IL-12/IL-23 deficiencies, by changing TGF-β/IL-6 levels.

Maternal schistosomiasis impairs offspring Interleukin-4 production and B cell expansion

Epidemiological studies have identified a correlation between maternal helminth infections and reduced immunity to some early childhood vaccinations, but the cellular basis for this is poorly understood. Here, we investigated the effects of maternal Schistosoma mansoni infection on steady-state offspring immunity, as well as immunity induced by a commercial tetanus/diphtheria vaccine using a dual IL-4 reporter mouse model of maternal schistosomiasis. We demonstrate that offspring born to S. mansoni infected mothers have reduced circulating plasma cells and peripheral lymph node follicular dendritic cells at steady state. These reductions correlate with reduced production of IL-4 by iNKT cells, the cellular source of IL-4 in the peripheral lymph node during early life. These defects in follicular dendritic cells and IL-4 production were maintained long-term with reduced secretion of IL-4 in the germinal center and reduced generation of TFH, memory B, and memory T cells in response to immunization with tetanus/diphtheria. Using single-cell RNASeq following tetanus/diphtheria immunization of offspring, we identified a defect in cell-cycle and cell-proliferation pathways in addition to a reduction in Ebf-1, a key B-cell transcription factor, in the majority of follicular B cells. These reductions are dependent on the presence of egg antigens in the mother, as offspring born to single-sex infected mothers do not have these transcriptional defects. These data indicate that maternal schistosomiasis leads to long-term defects in antigen-induced cellular immunity, and for the first time provide key mechanistic insight into the factors regulating reduced immunity in offspring born to S. mansoni infected mothers.

Maternal helminth infections are a global public health concern and correlate with altered infant immune responses to some childhood immunizations, but a mechanistic understanding of how maternal helminth infection alters the cellular immune responses of offspring is lacking. Here we establish a model of maternal Schistosoma mansoni infection in dual IL-4 reporter mice. We find that offspring born to mothers infected with S. mansoni have impaired production of IL-4 during homeostasis, and following immunization with a Tetanus-Diphtheria vaccine. We identified that iNKT cells are the dominant source of IL-4 during early life homeostasis, and that diminished IL-4 production was associated with both reduced B cell and follicular dendritic cell responses. These defects were maintained long-term, affecting memory B and T cell responses. Single-cell RNASeq analysis of immunized offspring identified egg antigen-dependent reductions in B-cell cell cycle and proliferation-related genes. These data reveal that maternal infection leads to long-lasting defects in the cellular responses to heterologous antigens and provide vital insight into the influence of maternal infection on offspring immunity.

Whey milk proteomics from Schistosoma mansoni-infected mice reveals proteins involved in immunomodulation of the offspring

Milk from schistosomotic mothers can modulate the immune response of their offspring. However, its characterization and potential of modulating immunity has not yet been fully elucidated. Thus, the aim of this study was to evaluate whey proteins from the milk of Schistosoma mansoni-infected mice in order to identify the fractions which can act as potential immunomodulatory tools. For this, we did a mass spectrometry (nanoUPLC-MSE) analysis to characterize the proteomic profile of milk from infected (MIM) and non-infected mice (MNIM). It was possible to identify 29 differentially expressed proteins: 15 were only found in MIM, 10 only found in MNIM, and 4 were downregulated in MIM group. Gene Ontology (GO), pathway enrichment analysis, and protein-protein interaction (PPI) analyses indicated differentially expressed proteins linked to biological processes and pathways in MIM group such as the following: fructose 1,6-biphosphate metabolic and glycolytic processes, glucose metabolism, and neutrophil degranulation pathways. The downregulated and unique proteins identified in MNIM group were involved in the positive regulation of B cell activation and receptor signaling pathway, in the innate immune response, complement activation, and phagocytosis. The present findings revealed a protein profile that may be involved in the activation and deactivation of the offspring's immune system in the long term, conferring a protective character due to the previous contact with milk from infected mothers.

Gestation and breastfeeding in schistosomotic mice differentially alters the expression of histone deacetylases (HDACs) in adult offspring

BACKGROUND

Breastfeeding or gestation in schistosomotic mothers can cause long-term alterations in the immune response of offspring.

OBJECTIVES

Evaluate the expression of histone deacetylases (HDACs) (all classes), the production of cytokines by T and B lymphocytes and macrophages, and the frequency of CD4⁺CD25⁺FoxP3⁺-cells in adult offspring born and/or suckled by schistosomotic mothers.

METHODS

We harvested splenocytes from offspring born to (BIM), suckled by (SIM), or born to/suckled by (BSIM) schistosomotic mothers and animals from noninfected mothers (Control) at seven-weeks old and cultured them with/without Concanavalin A. HDAC expression was evaluated by real-time quantitative polymerase chain reaction (qPCR), and cytokines and membrane markers were evaluated by fluorescence-activated cell sorting (FACS).

FINDINGS

Compared to Control, BIM mice showed increased expression of HDAC9 and frequency of CD4⁺IL-10⁺-cells. The SIM group had increased expression of HDAC1, HDAC2, HDAC6, HDAC7, HDAC10, Sirt2, Sirt5, Sirt6, and Sirt7. The BSIM group only had increased HDAC10 expression. The SIM and BSIM groups exhibited decreased frequencies of CD4⁺IL-4⁺-cells and CD4⁺CD25⁺FoxP3⁺-cells, along with a higher frequency of CD14⁺IL-10⁺-cells and an increase in CD45R/B220⁺IL-10⁺-cells. The BSIM group also showed a high frequency of CD4⁺IL10⁺-cells.

MAIN CONCLUSIONS

Breastfeeding induced the expression of HDACs from various classes involved in reducing inflammatory responses. However, gestation enhanced the expression of a single HDAC and breastfeeding or gestation appears to favour multiple IL-10-dependent pathways, but not cells with a regulatory phenotype.

Maternal Schistosomiasis: Immunomodulatory Effects With Lasting Impact on Allergy and Vaccine Responses

Early exposure to immune stimuli, including maternal infection during the perinatal period, is increasingly recognized to affect immune predisposition during later life. This includes exposure to not only viral and bacterial infection but also parasitic helminths which remain widespread. Noted effects of helminth infection, including altered incidence of atopic inflammation and vaccine responsiveness, support further research into the impact these infections have for skewing immune responses. At the same time, despite a sea of recommendations, clear phenotypic and mechanistic understandings of how environmental perturbations in pregnancy and nursing modify immune predisposition and allergy in offspring remain unrefined. Schistosomes, as strong inducers of type 2 immunity embedded in a rich network of regulatory processes, possess strong abilities to shift inflammatory and allergic diseases in infected hosts, for example by generating feedback loops that impair T cell responses to heterologous antigens. Based on the current literature on schistosomiasis, we explore in this review how maternal schistosome infection could drive changes in immune system development of offspring and how this may lead to identifying factors involved in altering responses to vaccination as well as manifestations of immune disorders including allergy.

Immune response to purified protein derivative in infants from helminth-sensitized mothers - A cases series

BACKGROUND

Maternal exposure to antibodies, cytokines or parasitic antigens during gestation may alter the degree of immune competence of offspring. Here we describe the production of cytokines and chemokines, and the ability to activation of the immune response in infants from mothers sensitized to helminths.

METHODS

It were selected five infants born to helminth-seropositive mothers but who were negative for current helminth infection. Whole blood was cultured without stimulus, with phytohemagglutinin mitogen (5 μg/ml, 24 h) or with purified protein derivative (PPD) (1 μg/ml, 24 h), and the supernatant was assessed for presence of Th1/Th2 cytokines (IFN-γ, TNF-α, IL-10, IL-5, IL-4 and IL-2) and chemokines (CXCL10, CCL2, CXCL9, CCL5 and CXCL8) by cytometric bead array.

RESULTS

All infants produced CCL5. Two infants demonstrated a mixed profile of Th1 (CXCL9) and Th2 (CCL2) chemokines in the presence of CXCL10, while one infant showed skewing towards Th2 without CXCL10 and two of them had been impaired immune response (children from sensitized to Schistosoma mansoni mothers).

CONCLUSION

Infants with Th1 and Th2 profile chemokines demonstrated a good response to vaccination, indicated by CXCL10 levels, but not infants predominantly Th2-skewed profile. These results highlight that children from mothers sensitized to S. mansoni may lead to ineffective immune response to PPD, while mothers sensitized to Ascaris lumbricoides showed no such impairment.

Infection by Schistosoma mansoni during pregnancy: Effects on offspring immunity

About 25 million Brazilians live in areas at risk of contracting the disease caused by the trematoda Schistosoma mansoni, the schistosomiasis mansoni. Although the adult parasites inhabit the blood vessels, probably the main element responsible for the pathology of the disease are the eggs, whose deposition in the liver results in formation of granulomas and hypersensitivity mediated by CD4 T cells. In the course of infection, the profile of T helper 1 (Th1) and Th2 cytokines released by immune cells is correlated with the extent of inflammation in the granuloma and with the disease severity. While a Th1 immune response favors the local inflammation and the disease progression, the Th2 immune response has protective character. Also during pregnancy, it is essential a fine adjustment of a Th1/Th2 in the maternal-fetal interface, which ensures the pregnancy progress with peculiar immune characteristics. In particular, the maternal exposure to antigens has been associated with their presence in fetal circulation. The exposure to intrauterine antigens can imply an immune tolerance of the fetus to such components. In turn, the transfer of antigens and antibodies from mother to offspring during breastfeeding is an important stage of maturation and capacitation of immune offspring in future infections against pathogens. This review aims to gather bibliographic data to assist in the understanding of immunological features printed on offspring of mothers infected with S. mansoni, which affect latter immune responses to related or unrelated antigens.

Gestation and breastfeeding in schistosomotic mothers differently modulate the immune response of adult offspring to postnatal Schistosoma mansoni infection

Schistosoma mansoni antigens in the early life alter homologous and heterologous immunity during postnatal infections. We evaluate the immunity to parasite antigens and ovalbumin (OA) in adult mice born/suckled by schistosomotic mothers. Newborns were divided into: born (BIM), suckled (SIM) or born/suckled (BSIM) in schistosomotic mothers, and animals from noninfected mothers (control). When adults, the mice were infected and compared the hepatic granuloma size and cellularity. Some animals were OA + adjuvant immunised. We evaluated hypersensitivity reactions (HR), antibodies levels (IgG1/IgG2a) anti-soluble egg antigen and anti-soluble worm antigen preparation, and anti-OA, cytokine production, and CD4⁺FoxP3⁺T-cells by splenocytes. Compared to control group, BIM mice showed a greater quantity of granulomas and collagen deposition, whereas SIM and BSIM presented smaller granulomas. BSIM group exhibited the lowest levels of anti-parasite antibodies. For anti-OA immunity, immediate HR was suppressed in all groups, with greater intensity in SIM mice accompanied of the remarkable level of basal CD4⁺FoxP3⁺T-cells. BIM and SIM groups produced less interleukin (IL)-4 and interferon (IFN)-g. In BSIM, there was higher production of IL-10 and IFN-g, but lower levels of IL-4 and CD4⁺FoxP3⁺T-cells. Thus, pregnancy in schistosomotic mothers intensified hepatic fibrosis, whereas breastfeeding diminished granulomas in descendants. Separately, pregnancy and breastfeeding could suppress heterologous immunity; however, when combined, the responses could be partially restored in infected descendants.