Interleukin-10 in murine metal-induced systemic autoimmunity

Systemic autoimmune diseases have a complicated and largely unknown aetiology and pathogenesis, but they are at least partly obeying the rules of an ordinary immune response. Cytokines are therefore important in the pathogenesis as demonstrated by the recent success in treating rheumatoid arthritis with anti-cytokine agents. The suppressive functions in the immune system have lately received much interest. One of the cytokines in focus in this respect is interleukin (IL)-10. We recently observed that in heavy-metal induced systemic autoimmunity, genetically resistant mice show a strong increase in IL-10 mRNA expression, which was not seen in susceptible mice. We have therefore examined the possible regulating effect of IL-10 on the induction and manifestation of systemic autoimmunity in this model. We took two approaches: a targeted mutation of the IL-10 gene in a strain resistant to heavy metal-induced autoimmunity, and treatment with recombinant IL-10 in the genetically susceptible A.SW strain during the induction of autoimmunity by metals. The wild-type C57BL/6 J (B6-WT) strain did not react with lymphoproliferation, polyclonal B cell activation, anti-nucleoar autoantibodies (ANoA) or tissue immune-complex (IC) deposits in response to inorganic mercury (Hg) or silver (Ag). However, serum IgG1 and IgE showed a modest increase during Hg treatment, while Ag caused a weak increase in IgE and IgG2a. The B6.129P2-Il10(tm1Cgn)/J strain (IL-10-deficient mice) did not develop antinucleolar antibodies (ANoA) during Hg treatment, but showed a higher median titre of homogeneous ANA compared with Hg-treated B6-WT mice. Both control and Hg-treated (but not Ag-treated) IL-10-deficient mice showed an increase in splenic weight and serum IgG1 compared with B6-WT control and Hg-treated mice. An early, significant increase in serum IgE was seen in Hg-treated IL-10-deficient and WT mice compared with the controls; the increase was 42- and sixfold, respectively. During ongoing intense treatment with rIL-10 in combination with Hg the susceptible A.SW mice showed a reduced development of ANoA and antichromatin antibodies, as well as serum IgE, compared with mice receiving Hg but not rIL-10. In conclusion, IL-10 suppresses several aspects of HgIA, but is not crucial for resistance to heavy metal-induced autoimmunity. Peroral silver treatment suppresses the spontaneous immune activation seen in IL-10-deficient mice.     

The role of Fc-receptors in murine mercury-induced systemic autoimmunity

Inorganic mercury (Hg) in genetically susceptible mouse strains induces a T cell-dependent, systemic autoimmune condition (HgIA) characterized by immunostimulation, anti-nuclear antibodies (ANA) and systemic immune-complex (IC) deposits. The exact phenotypic expression of HgIA in different strains depends on H-2 and non-H-2 genes. Fc receptors (FcRs) are important in the development of many autoimmune diseases. In this study, the effect of targeted mutations for activating and inhibiting FcRs in the BALB/c model of HgIA was examined. Hg-treated BALB/c mice without mutation (wild-type, wt) showed heavy IC deposits in the renal glomerular mesangium, as well as in renal and splenic vessel walls. The renal mesangial IC deposits were severely reduced in Hg-treated BALB/c mice without the gamma-chain (lack of the activating receptors FcgammaRI, FcgammaRIII and FcinRI), but unchanged in mice lacking the inhibitory FcgammaRIIB. The Hg-induced vessel wall IC deposits present in wt mice were abolished and reduced in the FcRgamma and FcgammaRIIB strains, respectively. Hg-treated BALB/c wt mice and mice without the gamma-chain showed an increase in serum IgE, while the increase in IgG1 was attenuated in the latter strain. In contrast, absence of the inhibiting FcgammaRIIB augmented the Hg-induced increase of both serum IgG1 and IgE. In conclusion, FcRs are important mainly for the induction of systmeic IC deposits in the HgIA model, but also affects serum IgG1 and IgE levels.     

The effect of activating and inhibiting Fc-receptors on murine mercury-induced autoimmunity

Fc-receptors for IgG (FcgammaR) link cellular and humoral immune responses, controlling the balance between activating and inhibitory immune responses, and are involved in autoimmune diseases. Mercury (Hg) induces an autoimmune condition in genetically (H-2(s,q,f)) susceptible mice characterized by lymphoproliferation, hypergammaglobulinemia and IgG antinucleolar antibodies (ANoA). Here we investigate the role of activating (FcgammaRI, FcgammaRIII) and inhibitory (FcgammaRIIb) Fc-receptors on mercury-induced autoimmunity (HgIA) using DBA/1 mice (H-2(q)) with targeted FcgammaR mutations and wild type (wt) mice. Mice deficient for the FcRgamma-chain or FcgammaRIII and treated with 15 mg/L HgCl(2) showed a delayed and attenuated IgG1, IgG2a and IgG2b ANoA response compared to wt mice. Female Hg-treated FcgammaRIIB(-/-) mice showed a significant increased of IgG2b ANoA development compared to wt mice. The total serum IgG1 response due to Hg was attenuated in FcRgamma(-/-) and FcgammaRIII(-/-) mice compared to wt mice. Hg-treated FcgammaRIIB(-/-) mice showed an increase of both serum IgG1 and IgE compared to wt mice. We conclude that FcgammaRIII is of importance for the rapidity and final strength of the ANoA response and the increase in serum IgG1 in HgIA, while lack of FcgammaRIIb increases the IgG2b ANoA response and the serum IgG1 and IgE response.     

Mercury-induced autoimmunity in the absence of IL-4

In susceptible H-2^s mice, mercuric chloride (HgCl₂) induces an autoimmune syndrome characterized by production of anti-nucleolar antibodies (ANoA) and increased serum levels of IgG1 and IgE antibodies. The increase in serum IgG1 and IgE, which are under IL-4 control, suggests a role for the Th2 subset in the induction of this syndrome. We have previously shown that administration of IL-12, a potent Th1-promoting cytokine, resulted in a dramatic reduction of the HgCl₂-induced anti-nucleolar antibody titres and inhibited serum IgG1 increase. These results suggest that Th1 T cells can down-regulate ANoA, and support a role for the Th2 subset in ANoA production, possibly via IL-4. To examine the role of IL-4 in this syndrome, C57Bl/6 mice (H-2^b) with a targeted deletion of the IL-4 gene were mated with A.SW mice (H-2^s) to yield H-2^s mice lacking IL-4. We then analysed ANoA and serum immunoglobulin levels in these mice after HgCl₂ treatment. While mercury-treated IL-4^−/− H-2^s mice had virtually no detectable serum IgG1 or IgE, and very low levels of IgG1 ANoA, these mice had levels of IgG2a and IgG2b class ANoA comparable to mercury-treated IL-4⁺ H-2^s mice, indicating that IL-4 is not required for the ANoA response in mercury-induced autoimmunity.     

Analysis of mercury-induced immune activation in nonobese diabetic (NOD) mice

In susceptible mice, the heavy metal ion mercury is able to induce a strong immune activation, which resembles a T helper 2 (Th2) type of immune response and is characterized by a polyclonal B cell activation, formation of high levels of IgG1 and IgE antibodies, production of autoantibodies of different specificities and development of renal IgG deposits. In the present study, we analysed the in vivo effects of mercury in nonobese diabetic (NOD) mice, which is believed to develop a spontaneous Th1 cell-mediated autoimmune diabetes similar to type 1 diabetes in humans. Three weeks of treatment with mercury induced a strong Th2 like immune/autoimmune response in NOD mice. This response was characterized by an intensive increase in splenic IgG1 antibody secreting cells, a marked elevation in serum IgE levels, a substantial increase in splenic IL-4 mRNA, but a significant decrease in splenic IFN-gamma mRNA. Mercury-induced IgG1 antibodies were mainly against ssDNA, TNP and thyroglobulin, but not against nucleolar antigen. Moreover, mercury-injected NOD mice developed high titres of IgG1 deposits in the kidney glomeruli. We further tested if the generated Th2 response could interfere with the development of insulitis and diabetes in NOD mice. We found that three weeks of treatment with mercury was also able to significantly suppress the development of insulitis and postpone the onset of diabetes in these mice. Thus, mercury-induced immune activation can counter-regulate the Th1 cell-mediated autoimmune responses and confer a partial protection against autoimmune diabetes in NOD mice.     

B7-1 and B7-2 co-stimulatory molecules are required for mercury-induced autoimmunity

B7-1 (CD80) and B7-2 (CD86) molecules on antigen presenting cells play important roles in providing co-stimulatory signals required for activation and expansion of autoreactive T cells. Moreover, some reports have suggested that these molecules may have distinct functions in the differentiation of Th1 and Th2 cells. Mercury-induced autoimmunity in H-2s mice is characterized by lymphoproliferation of T and B cells, serum increases in IgG1 and IgE and production of antinucleolar antibodies (ANoA). The mechanisms responsible for the various manifestations of this syndrome have yet to be elucidated. To examine the contributions of B7 co-stimulatory molecules to this model, susceptible mice were treated with antibodies to B7-1, B7-2, or both during the development of mercury-induced autoimmunity. The combination of anti-B7-1 and anti-B7-2 antibodies prevented Hg-induced disease in H-2s mice. Additionally, single anti-B7-1 antibody treatment was sufficient to prevent Hg-induced ANoA production, but not IgG1 and IgE hypergammaglobulinaemia. Further, single antibody treatment with anti-B7-2 resulted in a partial reduction of ANoA titres but had no significant effect on total serum IgG1 and IgE levels. Taken together, these results indicate that B7-1 and B7-2 molecules are critical for the development of Hg-induced autoimmunity and suggest that the different manifestations of the syndrome are regulated by independent mechanisms.     

Selective induction of anti-fibrillarin autoantibodies by silver nitrate in mice.

Female SJL (H-2s) mice developed serum IgG anti-nucleolar antibodies (ANoA) after 5 weeks treatment with 0.05% or 0.01% silver nitrate (AgNO3) in drinking water. Five more weeks of treatment increased the ANoA titre to 3410 +/- 853 and 640 +/- 175 (reciprocal mean +/- s.e.m.), respectively. Controls receiving ordinary tap water and mice given 0.002% AgNO3 showed no antinucleolar antibodies. The high-titre ANoA targeted a 34-kD nucleolar protein identified as fibrillarin, the major autoantigen in murine mercury-induced autoimmunity and in a fraction of patients with systemic scleroderma. Serum autoantibodies to chromatin or histones, kidney, spleen, stomach, thyroid, or skin antigens (except the nucleolus) were not found in any of the mice. There was no consistent significant increase of serum IgG1, IgG2a, IgG2b, or IgG3 concentrations after AgNO3 treatment compared with controls. Mice treated with 0.05% AgNO3 for 10 weeks showed a slight decrease in serum IgG1, IgG2b and IgG3 concentrations. These mice also showed a small but statistically significant increase in renal, mesangial IgM deposits, which was not accompanied by any increase in C3c deposits, whereas mice given lower doses of silver nitrate showed no significant increase in mesangial immunoglobulin immune deposits. Systemic vessel wall immune deposits were not found in any of the mice. In mice given 0.05% silver nitrate, the kidney showed the highest concentration of silver (12.2 +/- 0.09 micrograms Ag/g wet weight; mean +/- s.e.m.), followed by the spleen (8.7 +/- 1.3), and the liver (3.9 +/- 0.4). Treatment with 0.01% silver nitrate caused a different distribution of silver, with the highest concentration in the spleen (2.1 +/- 0.16 micrograms Ag/g), followed by the kidney (0.63 +/- 0.037), and the liver (< 0.29 micrograms Ag/g; mean). Silver seems to be a more specific inducer of antinucleolar/anti-fibrillarin autoantibodies than mercury and gold, lacks the general immune stimulating potential of mercury, and has only a weak tendency to induce renal immune deposits. These observations suggest that the autoimmune sequelae induced in mice by metals is dependent, not only upon the genetic haplotype of the murine strain, but also on the metal under investigation.     

Immunosuppressant effect of gold on IgG subclasses and IgE; evidence for sparing of Th2 responses

We set out to examine the effect of gold treatment on the Th2-dependent antibodies IgG4 and IgE in relation to other IgG subclasses in patients with rheumatoid arthritis (RA). Eighty-five gold-treated RA patients and 82 RA controls were studied. Serum IgG subclass concentrations were measured by ELISA, IgE was measured by automated enzyme immunoassay. Samples were studied serially in 13 gold-treated patients and in 11 patients with gold-induced adverse events. There was a significant reduction in the concentration of IgG1, IgG2 and IgG3 in gold-treated RA patients compared with RA controls (P 0.004-0.019), whereas IgG4 was less significantly reduced in gold-treated patients (P = 0.044) and there was no difference in IgE. In serial samples there was a significant fall in the concentration of IgG1 (P = 0.001), IgG2 (P = 0.001) and IgG3 (P = 0.026) with time but no change in IgG4 and IgE. The development of gold-induced adverse events was not associated with any change in the concentration of each IgG subclass or IgE. Deficiencies of IgG subclasses were found in 30% of gold-treated RA patients and 8.5% of RA controls, and were associated in gold-treated patients with a longer disease duration (P = 0.003) and with erosive disease (P = 0. 03). IgG2 was affected most frequently and in the majority of these cases subnormal specific IgG2 binding to widespread polysaccharide antigens (Pneumovax II) was found. Gold induces an overall immunosuppressant effect on IgG subclasses, with a deficiency in 21. 5%, adjusted for controls. The effect on the Th2-dependent antibodies IgG4 and IgE is less marked, suggesting a sparing of Th2 responses.     

Acceleration of IgE responses by treatment with recombinant interleukin-3 prior to infection with Trichinella spiralis in mice.

Treatment of mice with recombinant interleukin-3 (rIL-3) accelerated an IL-4-dependent IgE production following infection with Trichinella spiralis. When mice were treated with a total of 1.5 x 10(4) units rIL-3 for 5 days before infection with 400 muscle larvae, the serum IgE level increased prominently on day 5. Acceleration of IgE responses was dependent on the dose of rIL-3 injected. Treatment of mice with a total of 10(3) units rIL-3 could accelerate IgE responses. IgE responses were detected by a sandwich enzyme-linked immunosorbent assay at least from day 3 in mice treated with rIL-3. Acceleration of IgE responses was inhibited by anti-IL-4 monoclonal antibody. In contrast to this, IgG1 and IgG2a responses were not suppressed by the anti-IL-4 treatment. IL-3 treatment could up-regulate IgE and IgG1 responses but not the IgG2a response. IL-3 treatment could also accelerate IgE responses in W/Wv mice infected with the parasites. These results suggest that IL-3 is involved in regulation of IgE responses in mice and that mast cells do not play an essential role in acceleration of IgE responses induced by rIL-3 treatment in this system.     

Epicutaneous immunization converts subsequent and established antigen-specific T helper type 1 (Th1) to Th2-type responses

Epicutaneous immunization is a potential novel technique for topical vaccine delivery. It targets the immunologically rich milieu of the skin while having the advantage of being a non-invasive immunization procedure. By disrupting the stratum corneum of the epidermis a natural adjuvant effect can be achieved through activation of resident Langerhans cells. This negates the normal need for co-application of noxious adjuvants. Epicutaneous immunization on barrier-disrupted skin induces potent antigen-specific systemic immunity with a strong T helper type 2 (Th2) bias. We show here that epicutaneous immunization enhances the vigour of a subsequent T-cell response to the same antigen. The induced systemic Th2 response prevents the development of Th1 responses induced through injection of antigen in complete Freund's adjuvant (CFA). Prior epicutaneous immunization results in reduced production of antigen-specific interferon-gamma and immunoglobulin G2a (IgG2a) and enhanced interleukin-4, IgG1 and IgE responses to immunization with CFA. Moreover, epicutaneous immunization converts an established Th1 response to a Th2 response, as demonstrated by the specific reduction of interferon-gamma and IgG2a and the enhancement of interleukin-4 and IgE. This Th2 dominance of epicutaneous immunization may have direct therapeutic application as an immune-modulating procedure in Th1-dominant diseases such as autoimmune rheumatoid arthritis, type 1 diabetes, Hashimoto's thyroiditis and multiple sclerosis.     

Bacterial lipopolysaccharide both renders resistant mice susceptible to mercury-induced autoimmunity and exacerbates such autoimmunity in susceptible mice

The initiation and severity of systemic autoimmune diseases are influenced by a variety of genetic and environmental factors, in particular bacterial infections and products. Here, we have employed bacterial lipopolysaccharide (LPS), which non-specifically activates the immune system, to explore the involvement of innate immunity in mercury-induced autoimmunity in mice. Following treatment of mouse strains resistant [DBA/2 (H-2(d))] or susceptible [SJL(H-2(s))] to such autoimmunity with mercuric chloride and/or LPS or with physiological saline alone (control), their immune/autoimmune responses were monitored. Resistant DBA/2 mice were rendered susceptible to mercury-induced autoimmunity by co-administration of LPS, exhibiting pronounced increases in the synthesis of IgG1 and IgE, high titres of IgG1 deposits in the kidneys and elevated circulating levels of IgG1 antibodies of different specificities. Furthermore, the percentages of the T cells isolated from the spleens of DBA/2 mice exposed to both mercury and LPS that produced pro-inflammatory cytokines were markedly increased by in vitro stimulation with phorbol myristate acetate (PMA) and ionomycin, which was not the case for splenic T cells isolated from mice receiving mercuric chloride, LPS or saline alone. In addition, exposure of susceptible SJL mice to mercury in combination with LPS aggravated the characteristic features of mercury-induced autoimmunity, including increased synthesis of IgG1 and IgE, the production of IgG1 anti-nucleolar antibodies (ANolA) and the formation of renal deposits of IgG1. In summary, our findings indicate that activation of the innate immune system plays a key role in both the induction and severity of chemically induced autoimmunity.     

Severe hypercholesterolaemia leads to strong Th2 responses to an exogenous antigen

Severe hypercholesterolaemia is associated with decreased levels of immunoglobulin G2a (IgG2a) antibodies [T-helper 1 (Th1) response] to modified malondialdehyde-modified low-density lipoprotein (MDA-LDL) and increased levels of Th2-dependent IgG1 antibodies in apolipoprotein E-deficient (apoE(-/-)) mice. To investigate whether this reflects a general pattern of metabolic regulation of the humoral immune response, apoE(-/-) mice were fed diets resulting in different degrees of hypercholesterolaemia and immunized with keyhole limpet haemocyanin (KLH) in aluminium hydroxide. Cholesterol levels for different treatment groups ranged from 14 to 77 mmol/l in serum and from 10 to 39 mmol/g in liver. Mice with severe hypercholesterolaemia had increased IgG1 antibodies to MDA-LDL and decreased IgG2a anti-MDA-LDL. Importantly, titres of IgG2a antibodies to KLH were also decreased, while IgE anti-KLH was increased, with a corresponding induction of interleukin-4 (IL-4) and IL-10 and a decrease in interferon-gamma (IFN-gamma) in KLH-stimulated spleen cells in vitro. Thus, hypercholesterolaemia clearly affects antibody production both to the autoantigen MDA-LDL and to the exogenous antigen KLH, favouring antibody isotypes (IgG1 and IgE) that are dependent on Th2 help to B cells. Nuclear receptors ligated by oxidized lipid derivatives modulate T-cell responses, and it is speculated that this mechanism may cause the switch to Th2 in severe hypercholesterolaemia.     

Interleukin-12 regulates the proliferation of Th1, but not Th2 or Th0, clones

Our results indicate that interleukin (IL)-12 is an important costimulator of antigen-dependent proliferation of murine Th1 clones. In addition, we demonstrate that IL-10 inhibits splenic antigen-presenting cell (APC)-dependent proliferation of Th1 clones, at least in part, via down-regulation of APC-derived IL-12. Moreover, the failure of activated B cells to provide costimulation via IL-12 accounts for their inability to support optimal proliferative responses of Th1 clones. We also show that IL-12 regulates the ability of Th1 clones to respond to IL-4 and enhances their proliferation in response to IL-2, IL-7, or IL-15. In contrast, Th2 and Th0 clones appear refractory to the effects of IL-12 on antigen-dependent or growth factor-induced proliferation.     

Experimental Autoimmune Myocarditis in A/J mice Is an Interleukin-4-Dependent Disease with a Th2 Phenotype

Myocarditis in humans is often associated with an autoimmune process in which cardiac myosin (CM) is a major autoantigen. Experimental autoimmune myocarditis (EAM) is induced in mice by immunization with CM. We found that EAM in A/J mice exhibits a Th2-like phenotype demonstrated by the histological picture of the heart lesions (eosinophils and giant cells) and by the humoral response (association of IgG1 response with disease and up-regulation of total IgE). Blocking interleukin (IL)-4 with anti-IL-4 monoclonal antibody (mAb) reduced the severity of EAM. This reduction in severity was associated with a shift from a Th2-like to a Th1-like phenotype represented by a reduction in CM-specific IgG1; an increase in CM-specific IgG2a; an abrogation of total IgE response; a decrease in IL-4, IL-5, and IL-13; as well as a dramatic increase in interferon (IFN)-gamma production in vitro. Based on the latter finding, we hypothesized that IFN-gamma limits disease. Indeed, IFN-gamma blockade with a mAb exacerbated disease. The ameliorating effect of IL-4 blockade was abrogated by co-administration of anti-IFN-gamma mAb. Thus, EAM represents a model of an organ-specific autoimmune disease associated with a Th2 phenotype, in which IL-4 promotes the disease and IFN-gamma limits it. Suppression of IFN-gamma represents at least one of the mechanisms by which IL-4 promotes EAM.     

Splenic PGE2-releasing macrophages regulate Th1 and Th2 immune responses in mice treated with heat-killed BCG

Hosts infected with low doses of mycobacteria develop T helper cell type 1 (Th1) immunity, but at relatively higher doses, a switch to Th2 immunity occurs. Prostaglandin E2 (PGE2) is a proposed mediator of the Th1-to-Th2 shift of immune responses, and mycobacterial products induce PGE2-releasing macrophages (PGE2-M?) in the mouse spleen in a dose-dependent manner. Splenic PGE2-M ? from Balb/c mice, given 0.01 or 1 mg heat-killed (HK) Mycobacterium bovis bacillus Calmette-Guerin (BCG) intraperitoneally (i.p.), were characterized by the ex vivo release of PGE2 (>10 ng/10(6) cells), cytokine production, and expression of PGG/H synthase (PGHS)-1, PGHS-2, cytosolic PGE synthase (PGES), and microsomal PGES-1. At Day 14 after the treatment, mice treated with 1 mg, but not 0.01 mg, BCG had increased levels of PGHS-2+ PGE2-M?, total serum immunoglobulin E (IgE), and serum IgG1 antibodies (Th2 responses) against heat shock protein 65 and purified protein derivative. Cultures of spleen cells isolated from these mice expressed interleukin (IL)-4 and IL-10 in recall responses. Treatment of mice receiving 1 mg BCG with NS-398 (a PGHS-2 inhibitor, 10 mg/kg i.p., daily) resulted in enhanced interferon-gamma (IFN-gamma) production with reduced IL-4 and IL-10 production in recall responses. This treatment also resulted in decreased total serum IgE levels. Treatment of C57Bl/6 mice with HK-BCG (0.5 mg dose) also induced a mixture of Th1 and Th2 responses, although IFN-gamma production was markedly increased, and IL-4 was decreased compared with Balb/c mice. Thus, our results indicate that by 14 days following treatment of mice with high doses of HK-BCG, splenic PGE2-M? formation is associated with a PGHS-2-dependent shift from Th1-to-Th2 immune responses.     

Immunostimulatory oligodeoxynucleotide from Bifidobacterium longum suppresses Th2 immune responses in a murine model

We have reported previously that novel immunostimulatory sequence (ISS) oligodeoxynucleotide (ODN) BL07S from a probiotic strain of Bifidobacterium longum inhibited immunoglobulin (Ig) E production in vitro. However, whether ISS-ODNs from probiotics regulate T helper type 2 (Th2)-polarized immune reactions in vivo remains unclear. To evaluate the inhibitory effects of ODN BL07S on type I allergic response, BALB/c mice were injected with or without ODN BL07S in the presence of ovalbumin (OVA) on days 0 and 14. Serum Ig levels (IgE, IgG1 and IgG2a) and cytokine levels (interferon (IFN)-gamma, interleukin (IL)-12, IL-4, IL-5, IL-10 and IL-13) were investigated in splenocyte cultures from days 14-28. Production of OVA-specific and total IgE were significantly suppressed by administration of ODN BL07S, but not by ODN BL06S, a non-ISS-ODN. Compared to controls, ODN BL07S induced significantly lower levels of Th2 cytokines (IL-4 and IL-5) in splenocyte cultures, and significantly higher levels of serum OVA-specific IgG2a. These effects of ODN BL07S on modulation of Th2 immune response were dose-dependent. The present results demonstrate that ODN BL07S from genomic DNA of B. longum BB536 prevents antigen-induced Th2 immune responses in vivo, suggesting that ISS-ODNs from probiotics might be useful in preventing allergic disease.     

Enhanced Th1 and dampened Th2 responses synergize to inhibit acute granulomatous and fibrotic responses in murine schistosomiasis mansoni

In murine schistosomiasis mansoni, CD4(+) Th1 and Th2 cells participate in the ovum-induced granulomatous inflammation. Previous studies showed that the interleukin-12 (IL-12)-induced Th1 response strongly suppressed the Th2-cell-mediated pulmonary granuloma development in naive or primed mice. However, liver granulomas were only moderately suppressed in egg-vaccinated, recombinant IL-12 (rIL-12)-treated infected mice. The present study shows that repeated rIL-12 injections given during early granuloma development at 5 to 7 weeks after infection prolonged the Th1 phase and resulted in gamma interferon-mediated suppression of liver granulomas. The timing is crucial: if given at 6 to 8 weeks, during the Th2-dominated phase of florid granuloma growth, the treatment is ineffective. Daily injections of rIL-12 given between 5 and 7.5 weeks during the period of granuloma growth achieved a somewhat-stronger diminution in granuloma growth with less deposition of collagen but caused 60% mortality and liver pathology. In contrast, combined treatment with rIL-12 and anti-IL-4-anti-IL-10 monoclonal antibody (MAb) injections given during the Th2 phase strongly inhibited liver granuloma growth without mortality. The diminished inflammatory response was accompanied by less deposition of collagen in the liver. Moreover, neutralization of endogenous IL-12 by anti-IL-12 MAbs effectively decreased the early Th1 phase (between 5 and 6 weeks after infection) but not the developing Th2 phase (5 to 7 weeks) of granuloma development. These studies indicate that the granulomatous response in infected mice can be manipulated by utilizing the Th1-Th2-subset antagonism with potential salutary results in the amelioration of fibrous pathology.