Immunogenetics of Trichuris muris infection

Investigations have been made into the genetic control of immunity to the nematode Trichuris muris. Both background genes and genes within the mouse major histocompatibility complex (MHC), H-2, were shown to influence the expulsion of T. muris with the former having the stronger influence. At least two genes within the H-2 complex determined response phenotypes, the effects of "resistance" or "susceptibility" alleles at I-A being modulated by resistance or susceptibility alleles at aD end locus/loci. Differential responsiveness within slowly responding mouse strains suggested that parasite-dependent effects were also important. The primary antibody response to T. muris excretory/secretory (E/S) antigen, predominantly an IgG response, was also shown to be controlled by background and H-2-linked genes. In general, mouse strains less resistant to infection developed higher levels of IgG than- more resistant strains of mice. However strains of mice possessing the H-2q haplotype, irrespective of their genetic background, rapidly developed higher levels of IgG1 antibodies than strains of other haplotypes, H-2q haplotype mice tending to be more resistant to infection. Recognition of two high molecular weight (MW) E/S antigens by IgG as revealed by immunoprecipitation was also found to be almost exclusively H-2q restricted. This restriction may be partly quantitative but as such would operate in vivo due to the restriction on the ability to produce high levels of specific IgG. Both H-2q restricted phenomena may be part of, but not absolute requirements for, protective immunity. Parasite-induced effects on host immunity were also studied. Later larval and adult stages of T. muris were shown to be immunosuppressive, immunosuppression being long lasting and preventing the expulsion of subsequent infections. Vaccination with E/S antigen was shown to protect strains of mice which are slow to expel worms (poor-responder) or totally unable to expel worms (non-responder) from a primary infection with T. muris. However protection was slow to be expressed. Antigen recognition profiles of vaccinated strains of mice differed from their primary infection recognition profiles and included the recognition of the two high MW antigens shown to be H-2q restricted in a primary infection. Thus altering the mode or route of E/S antigen presentation may lead to shifts in responsiveness of H-2 genotypes to specific determinants and/or boost specific antibody levels sufficiently to reveal recognition of these antigens. Prior experience of a patent primary infection prevented vaccination protecting non-responder mice against subsequent infections. This inability was correlated with suppressed IgG1 antibody levels and failure to recognise three high MW antigens including the IL-2q restricted antigens. Using a panel of monoclonal antibodies raised against E/S antigen it was shown that E/S antigens, apparently including both immunogenic and immunosuppressive molecules, were localised to granules within the stichocyte cytoplasm of the adult T. muris stichosome

Immunogenetics of Trichuris muris infection

Investigations have been made into the genetic control of immunity to the nematode Trichuris muris. Both background genes and genes within the mouse major histocompatibility complex (MHC), H-2, were shown to influence the expulsion of T. muris with the former having the stronger influence. At least two genes within the H-2 complex determined response phenotypes, the effects of "resistance" or "susceptibility" alleles at I-A being modulated by resistance or susceptibility alleles at aD end locus/loci. Differential responsiveness within slowly responding mouse strains suggested that parasite-dependent effects were also important. The primary antibody response to T. muris excretory/secretory (E/S) antigen, predominantly an IgG response, was also shown to be controlled by background and H-2-linked genes. In general, mouse strains less resistant to infection developed higher levels of IgG than- more resistant strains of mice. However strains of mice possessing the H-2q haplotype, irrespective of their genetic background, rapidly developed higher levels of IgG1 antibodies than strains of other haplotypes, H-2q haplotype mice tending to be more resistant to infection. Recognition of two high molecular weight (MW) E/S antigens by IgG as revealed by immunoprecipitation was also found to be almost exclusively H-2q restricted. This restriction may be partly quantitative but as such would operate in vivo due to the restriction on the ability to produce high levels of specific IgG. Both H-2q restricted phenomena may be part of, but not absolute requirements for, protective immunity. Parasite-induced effects on host immunity were also studied. Later larval and adult stages of T. muris were shown to be immunosuppressive, immunosuppression being long lasting and preventing the expulsion of subsequent infections. Vaccination with E/S antigen was shown to protect strains of mice which are slow to expel worms (poor-responder) or totally unable to expel worms (non-responder) from a primary infection with T. muris. However protection was slow to be expressed. Antigen recognition profiles of vaccinated strains of mice differed from their primary infection recognition profiles and included the recognition of the two high MW antigens shown to be H-2q restricted in a primary infection. Thus altering the mode or route of E/S antigen presentation may lead to shifts in responsiveness of H-2 genotypes to specific determinants and/or boost specific antibody levels sufficiently to reveal recognition of these antigens. Prior experience of a patent primary infection prevented vaccination protecting non-responder mice against subsequent infections. This inability was correlated with suppressed IgG1 antibody levels and failure to recognise three high MW antigens including the IL-2q restricted antigens. Using a panel of monoclonal antibodies raised against E/S antigen it was shown that E/S antigens, apparently including both immunogenic and immunosuppressive molecules, were localised to granules within the stichocyte cytoplasm of the adult T. muris stichosome

Expulsion of Trichuris muris is associated with increased expression of angiogenin 4 in the gut and increased acidity of mucins within the goblet cell

<p>Abstract</p> <p>Background</p> <p><it>Trichuris muris </it>in the mouse is an invaluable model for infection of man with the gastrointestinal nematode <it>Trichuris trichiura</it>. Three <it>T. muris </it>isolates have been studied, the Edinburgh (E), the Japan (J) and the Sobreda (S) isolates. The S isolate survives to chronicity within the C57BL/6 host whereas E and J are expelled prior to reaching fecundity. How the S isolate survives so successfully in its host is unclear.</p> <p>Results</p> <p>Microarray analysis was used as a tool to identify genes whose expression could determine the differences in expulsion kinetics between the E and S <it>T. muris </it>isolates. Clear differences in gene expression profiles were evident as early as day 7 post-infection (p.i.). 43 probe sets associated with immune and defence responses were up-regulated in gut tissue from an E isolate-infected C57BL/6 mouse compared to tissue from an S isolate infection, including the message for the anti-microbial protein, angiogenin 4 (Ang4). This led to the identification of distinct differences in the goblet cell phenotype post-infection with the two isolates.</p> <p>Conclusion</p> <p>Differences in gene expression levels identified between the S and E-infected mice early during infection have furthered our knowledge of how the S isolate persists for longer than the E isolate in the C57BL/6 mouse. Potential new targets for manipulation in order to aid expulsion have been identified. Further we provide evidence for a potential new marker involving the acidity of the mucins within the goblet cell which may predict outcome of infection within days of parasite exposure.</p

The Goblet Cell Is the Cellular Source of the Anti-Microbial Angiogenin 4 in the Large Intestine Post Trichuris muris Infection

Mouse angiogenin 4 (Ang4) has previously been described as a Paneth cell-derived antimicrobial peptide important in epithelial host defence in the small intestine. However, a source for Ang4 in the large intestine, which is devoid of Paneth cells, has not been defined.Analysis was performed on Ang4 expression in colonic tissue by qPCR and immunohistochemistry following infection with the large intestine dwelling helminth parasite Trichuris muris. This demonstrated an increase in expression of the peptide following infection of resistant BALB/c mice. Further, histological analysis of colonic tissue revealed the cellular source of this Ang4 to be goblet cells. To elucidate the mechanism of Ang4 expression immunohistochemistry and qPCR for Ang4 was performed on colonic tissue from T. muris infected mouse mutants. Experiments comparing C3H/HeN and C3H/HeJ mice, which have a natural inactivating mutation of TLR4, revealed that Ang4 expression is TLR4 independent. Subsequent experiments with IL-13 and IL-4 receptor alpha deficient mice demonstrated that goblet cell expression of Ang4 is controlled either directly or indirectly by IL-13.The cellular source of mouse Ang4 in the colon following T. muris infection is the goblet cell and expression is under the control of IL-13

The gut-associated lymphoid tissues in the small intestine, not the large intestine, play a major role in oral prion disease pathogenesis

Prion diseases are infectious neurodegenerative disorders characterized by accumulations of abnormally folded cellular prion protein in affected tissues. Many natural prion diseases are acquired orally, and following exposure, the early replication of some prion isolates upon follicular dendritic cells (FDC) within gut-associated lymphoid tissues (GALT) is important for the efficient spread of disease to the brain (neuroinvasion). Prion detection within large intestinal GALT biopsy specimens has been used to estimate human and animal disease prevalence. However, the relative contributions of the small and large intestinal GALT to oral prion pathogenesis were unknown. To address this issue, we created mice that specifically lacked FDC-containing GALT only in the small intestine. Our data show that oral prion disease susceptibility was dramatically reduced in mice lacking small intestinal GALT. Although these mice had FDC-containing GALT throughout their large intestines, these tissues were not early sites of prion accumulation or neuroinvasion. We also determined whether pathology specifically within the large intestine might influence prion pathogenesis. Congruent infection with the nematode parasite Trichuris muris in the large intestine around the time of oral prion exposure did not affect disease pathogenesis. Together, these data demonstrate that the small intestinal GALT are the major early sites of prion accumulation and neuroinvasion after oral exposure. This has important implications for our understanding of the factors that influence the risk of infection and the preclinical diagnosis of disease. IMPORTANCE Many natural prion diseases are acquired orally. After exposure, the accumulation of some prion diseases in the gut-associated lymphoid tissues (GALT) is important for efficient spread of disease to the brain. However, the relative contributions of GALT in the small and large intestines to oral prion pathogenesis were unknown. We show that the small intestinal GALT are the essential early sites of prion accumulation. Furthermore, congruent infection with a large intestinal helminth (worm) around the time of oral prion exposure did not affect disease pathogenesis. This is important for our understanding of the factors that influence the risk of prion infection and the preclinical diagnosis of disease. The detection of prions within large intestinal GALT biopsy specimens has been used to estimate human and animal disease prevalence. However, our data suggest that using these biopsy specimens may miss individuals in the early stages of oral prion infection and significantly underestimate the disease prevalence

Intestinal epithelial Suppressor of Cytokine Signaling (SOCS) 3 enhances microbial induced inflammatory TNFα, contributing to epithelial barrier dysfunction

A single layer of intestinal epithelial cells (IEC) lines the entire GI tract and provides the first line of defence and barrier against an abundance of microbial stimuli. IEC homeostasis and repair are mediated through microbe-sensing Toll-like receptor (TLR)-induced inflammatory pathways. Increasing evidence supports a role of suppressor of cytokine signaling 3 (SOCS3) as a modulator of IEC turnover, balancing controlled repair and replenishment with excessive IEC proliferation predisposing to dysplasia and cancer. Our data indicate that SOCS3 can limit microbial-induced epithelial repair, promote TNFα, possibly through limiting TNFR2 expression in intestinal epithelial cells (IEC). Activation of TLR5 signalling pathways, compared with other TLR, increase TNFα mRNA in a dose dependent manner and SOCS3 enhances TLR5-induced TNFα. We also show that flagellin promotes transcription of TNFR2 and that SOCS3 may limit this expression, presenting a mechanism of SOCS3 action. Our data also supports the role of microbial ligands in epithelial wound healing and suggests that a functional consequence of increased TNFα is reduced wound healing. These results provide further evidence to support the regulatory role of epithelial SOCS3 in intestinal health and suggest that the increased expression of SOCS3 observed in IBD may serve to perpetuate 'inflammation' by promoting TNFα production and limiting epithelial repair in response to commensal microflora

Investigating the importance of B cells and antibodies during Trichuris muris infection using the IgMi mouse

From Springer Nature via Jisc Publications RouterHistory: received 2020-04-24, rev-recd 2020-06-24, registration 2020-07-17, accepted 2020-07-17, pub-electronic 2020-08-10, online 2020-08-10, pub-print 2020-09Publication status: PublishedFunder: Indonesian endowment fund for education, Phd StudentshipFunder: Biotechnology and Biological Sciences Research Council UK, PhD StudenshipFunder: Medical Research Council UK; Grant(s): MR/NO22661/1 to KJEFunder: Biotechnology and Biological Sciences Research Council UK; Grant(s): BB/P018157/1 to KJEAbstract: The IgMi mouse has normal B cell development; its B cells express an IgM B cell receptor but cannot class switch or secrete antibody. Thus, the IgMi mouse offers a model system by which to dissect out antibody-dependent and antibody-independent B cell function. Here, we provide the first detailed characterisation of the IgMi mouse post-Trichuris muris (T. muris) infection, describing expulsion phenotype, cytokine production, gut pathology and changes in T regulatory cells, T follicular helper cells and germinal centre B cells, in addition to RNA sequencing (RNA seq) analyses of wild-type littermates (WT) and mutant B cells prior to and post infection. IgMi mice were susceptible to a high-dose infection, with reduced Th2 cytokines and elevated B cell-derived IL-10 in mesenteric lymph nodes (MLN) compared to controls. A low-dose infection regime revealed IgMi mice to have significantly more apoptotic cells in the gut compared to WT mice, but no change in intestinal inflammation. IL-10 levels were again elevated. Collectively, this study showcases the potential of the IgMi mouse as a tool for understanding B cell biology and suggests that the B cell plays both antibody-dependent and antibody-independent roles post high- and low-dose T. muris infection. Key messages: During a high-dose T. muris infection, B cells are important in maintaining the Th1/Th2 balance in the MLN through an antibody-independent mechanism. High levels of IL-10 in the MLN early post-infection, and the presence of IL-10-producing B cells, correlates with susceptibility to T. muris infection. B cells maintain gut homeostasis during chronic T. muris infection via an antibody-dependent mechanism

The Retinoic Acid Receptor Agonist Am80 Increases Mucosal Inflammation in an IL-6 Dependent Manner During Trichuris muris Infection

PURPOSE: Vitamin A metabolites, such as all-trans-retinoic acid (RA) that act through the nuclear receptor; retinoic acid receptor (RAR), have been shown to polarise T cells towards Th2, and to be important in resistance to helminth infections. Co-incidentally, people harbouring intestinal parasites are often supplemented with vitamin A, as both vitamin A deficiency and parasite infections often occur in the same regions of the globe. However, the impact of vitamin A supplementation on gut inflammation caused by intestinal parasites is not yet completely understood. METHODS: Here, we use Trichuris muris, a helminth parasite that buries into the large intestine of mice causing mucosal inflammation, as a model of both human Trichuriasis and IBD, treat with an RARα/β agonist (Am80) and quantify the ensuing pathological changes in the gut. RESULTS: Critically, we show, for the first time, that rather than playing an anti-inflammatory role, Am80 actually exacerbates helminth-driven inflammation, demonstrated by an increased colonic crypt length and a significant CD4(+) T cell infiltrate. Further, we established that the Am80-driven crypt hyperplasia and CD4(+) T cell infiltrate were dependent on IL-6, as both were absent in Am80-treated IL-6 knock-out mice. CONCLUSIONS: This study presents novel data showing a pro-inflammatory role of RAR ligands in T. muris infection, and implies an undesirable effect for the administration of vitamin A during chronic helminth infection. ELECTRONIC SUPPLEMENTARY MATERIAL: The online version of this article (doi:10.1007/s10875-013-9936-8) contains supplementary material, which is available to authorized users