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T Germann

Publications and source records attributed to T Germann.

At least 19 recordsLinked to original sources
PubMed2000

CD154 stimulation of interleukin-12 synthesis in human endothelial cells.

The interaction of proinflammatory type 1 T helper (Th1) cells expressing the CD40 ligand (CD154) with endothelial cells expressing the corresponding receptor (CD40) may play an important role in chronic inflammation including arteriosclerosis. Here we demonstrate that activation of CD40 in human cultured endothelial cells (e.g. by interaction with freshly isolated human T cells) not only up-regulates expression of various adhesion molecules, chemokines and cytokines, but within 12-24 h also causes the release of bioactive interleukin-12 (IL-12 p70) through induction of IL-12 p40 synthesis. IL-12 p35, on the other hand, appears to be constitutively expressed in these cells. Despite enhancing expression of the other gene products, cytokines such as interferon-gamma (IFN-gamma) or tumor necrosis factor-alpha, alone or in combination, failed to induce IL-12 p40 expression, whereas IFN-gamma markedly augmented CD154-induced IL-12 p40 and p70 release. Of note was that the magnitude of CD154-induced IL-12 synthesis in the cultured endothelial cells was comparable to that evoked in freshly isolated human monocytes. This CD40-mediated induction of endothelial IL-12 synthesis may thus lead to an enhanced activation of the adherent CD154-expressing Th1 cells, thereby fuelling the proinflammatory response.

CD40 Ligand↗
PubMed1999

Endotoxin down-regulates T cell activation by antigen-presenting liver sinusoidal endothelial cells.

Endotoxin is physiologically present in portal venous blood at concentrations of 100 pg/ml to 1 ng/ml. Clearance of endotoxin from portal blood occurs through sinusoidal lining cells, i.e., Kupffer cells, and liver sinusoidal endothelial cells (LSEC). We have recently shown that LSEC are fully efficient APCs. Here, we studied the influence of endotoxin on the accessory function of LSEC. Incubation of Ag-presenting LSEC with physiological concentrations of endotoxin lead to >/=80% reduction of the accessory function, measured by release of IFN-gamma from CD4+ T cells. In contrast, conventional APC populations rather showed an increase of the accessory function after endotoxin treatment. Inhibition of the accessory function in LSEC by endotoxin was not due to lack of soluble costimulatory signals, because neither supplemental IL-1beta, IL-2, IFN-gamma, or IL-12 could rescue the accessory function. Ag uptake was not influenced by endotoxin in LSEC. However, we found that endotoxin led to alkalinization of the endosomal/lysomal compartment specifically in LSEC but not in bone marrow macrophages, which indicated that Ag processing, i.e., proteolytic cleavage of protein Ags into peptide fragments, was affected by endotoxin. Furthermore, endotoxin treatment down-regulated surface expression of constitutively expressed MHC class II, CD80, and CD86. In conclusion, it is conceivable that endotoxin does not alter the clearance function of LSEC to remove gut-derived Ags from portal blood but specifically affects Ag processing and expression of the accessory molecules in these cells. Consequently, Ag-specific immune responses by CD4+ T cells are efficiently down-regulated in the hepatic microenvironment.

Animals↗
PubMed1999

Effect of thalidomide and structurally related compounds on corneal angiogenesis is comparable to their teratological potency.

Neovascular diseases are the leading causes of blindness in humans. Although several promising compounds have been isolated, pharmacological treatment remains difficult. Thalidomide has inhibitory effects on angiogenesis in the corneal micropocket assay. However, the results vary considerably depending on the administration route and animal model. The aim of this study, therefore, was to investigate thalidomide and two of its derivatives, supidimide and EM12, in the rabbit corneal micropocket assay. Using both basic fibroblast growth factor and vascular endothelial growth factor for initiation of the neovascular response, we were able to show a significant inhibition of neovascularisation with all three substances. EM12, the most teratogenic derivative analysed, was demonstrated to be the most potent inhibitor of angiogenesis in this model. Thalidomide and supidimide did not show systemic side effects in the applied dosage. An equal dosage of EM12, however, resulted in significant weight loss of the animals, but did not increase angiogenic activity compared with lower doses. Together with earlier findings, these data support a strong correlation between the antiangiogenic potential and the teratogenic activity of thalidomide and structurally related compounds.

Administration, Oral↗
PubMed1999

Induction of cytokine production in naive CD4(+) T cells by antigen-presenting murine liver sinusoidal endothelial cells but failure to induce differentiation toward Th1 cells.

BACKGROUND & AIMS: Murine liver sinusoidal endothelial cells (LSECs) constitutively express accessory molecules and can present antigen to memory Th1 CD4(+) T cells. Using a T-cell receptor transgenic mouse line, we addressed the question whether LSECs can prime naive CD4(+) T cells. METHODS: Purified LSECs were investigated for their ability to induce activation and differentiation of naive CD4(+) T cells in comparison with bone marrow-derived antigen-presenting cells and macrovascular endothelial cells. Activation of T cells was determined by cytokine production. LSECs were further studied for expression of interleukin (IL)-12 by reverse-transcription polymerase chain reaction, and the unique phenotype of LSECs was determined by flow cytometry. RESULTS: We provide evidence that antigen-presenting LSECs can activate naive CD62Lhigh CD4(+) T cells. Activation of naive CD4(+) T cells by LSECs occurred in the absence of IL-12. In contrast, macrovascular endothelial cells from aorta could not activate naive CD4(+) T cells. The unique functional characteristics of microvascular LSECs together with a unique phenotype (CD4(+), CD11b+, CD11c+, CD80(+), CD86(+)) make these cells different from macrovascular endothelial cells. Furthermore, LSECs did not require in vitro maturation to activate naive CD4(+) T cells. Most importantly, LSECs failed to induce differentiation toward Th1 cells, whereas conventional antigen-presenting cell populations induced a Th1 phenotype in activated CD4(+) T cells. Upon restimulation, CD4(+) T cells, which were primed by antigen-presenting LSECs, expressed interferon gamma, IL-4, and IL-10, which is consistent with a Th0 phenotype. Exogenous cytokines (IL-1beta, IL-12, or IL-18) present during T-cell priming by antigen-presenting LSECs could not induce a Th1 phenotype, but neutralization of endogenously produced IL-4 during T-cell priming led to a reduced expression of IL-4 and IL-10 by CD4(+) T cells upon restimulation. The addition of spleen cells to cocultures of LSECs and naive CD4(+) T cells during T-cell priming led to differentiation of T cells toward a Th1 phenotype. CONCLUSIONS: The ability of antigen-presenting LSECs to induce cytokine expression in naive CD4(+) T cells and their failure to induce differentiation toward a Th1 phenotype may contribute to the unique hepatic microenvironment that is known to promote tolerance.

Animals↗
PubMed1999

Methotrexate specifically modulates cytokine production by T cells and macrophages in murine collagen-induced arthritis (CIA): a mechanism for methotrexate-mediated immunosuppression.

Immunosuppressive therapy with methotrexate (MTX) has been established as effective treatment for patients with rheumatoid arthritis. To analyse the therapeutic potential and mechanisms of action of MTX, we determined serum cytokine levels and cytokine production by splenic T cells and macrophages in untreated and MTX-treated mice. Furthermore, we assessed the role of MTX in a murine model of experimental arthritis induced by collagen type II (CIA). MTX reduced spontaneous and IL-15-induced tumour necrosis factor (TNF) production by splenic T cells but not by macrophages from healthy mice in vitro in a dose-dependent manner. In contrast, interferon-gamma (IFN-gamma) production was less strikingly reduced and IL-4 production was virtually unaffected. In addition, treatment of healthy mice with MTX in vivo led to reduced TNF serum levels and diminished TNF production by splenic T cells and macrophages. Intraperitoneal administration of MTX prior to the onset of arthritis completely prevented clinical and pathological signs of CIA. This was associated with a striking reduction of TNF production by spleen cells from MTX-treated mice. The role of TNF in MTX-mediated effects on cytokine production was further underlined by the finding that MTX effects on IFN-gamma production were augmented in TNF-transgenic mice but abrogated in mice in which the TNF-alpha gene had been inactivated by homologous recombination. Thus, MTX specifically modulates spontaneous and IL-15-induced TNF-alpha production in mice and prevents experimental murine CIA. These data suggest that TNF production by T cells is an important target of MTX and may serve as a basis to understand and further analyse MTX-mediated mechanisms of immunosuppression in patients with RA.

Animals↗
PubMed1997

The host response to Listeria monocytogenes mutants defective in genes encoding phospholipases C (plcA, plcB) and actin assembly (actA).

Several genes involved in the determination of Listeria monocytogenes pathogenesis have been identified. Among them, plcA gene encodes phosphatidylinositol-specific phospholipase C (PI-PLC), plcB gene encodes a broad-range phospholipase C (PC-PLC), and actA encodes a protein contributing to actin assembly in infected cells. The interaction of L. monocytogenes wild type (LO 28) strain and two derivative mutants, plcA- (BUG 206) and actA-/plcB- (LUT 12), with macrophages and T lymphocytes was investigated in a mouse model of listeriosis. Both mutants showed evidence of attenuation. The plcA- mutant, but not the plcB- mutant, expressed an increase in susceptibility to the anti-listerial activity of macrophages. Both mutants showed a decreased ability to induce IL-12 production by bone marrow macrophages when co-stimulated with E. coli LPS or IFN-gamma. In vivo, L. monocytogenes plcA- mutant was found to be a more effective stimulator of T cells than the wild LO 28 strain.

Actins↗
PubMed1996

Characterization of the adjuvant effect of IL-12 and efficacy of IL-12 inhibitors in type II collagen-induced arthritis.

A destructive joint disease can be induced in susceptible DBA/1 mice by immunization with type II collagen emulsified with oil and either killed Mycobacterium tuberculosis or IL-12 as adjuvant. Cellular and humoral anti-collagen immune mechanisms appear to be involved in the pathogenesis of arthritis. We have characterized the adjuvant effect or IL-12 in more detail and addressed the question whether mycobacteria might act via the induction of endogenous IL-12. Injections of IL-12 into collagen-immunized DBA/1 mice promoted the development of IFN-gamma-producing CD4+ T cells and strongly upregulated the production of complement-fixing IgG2a and IgG2b antibodies resulting in severe arthritis. Neutralization of IFN-gamma in vivo largely inhibited the increase in antibody synthesis and prevented joint disease in IL-12-treated mice. However, collagen-specific IFN-gamma synthesis by T cells was further enhanced in these animals. Furthermore, IL-12 treatment promoted the development of IFN-gamma-producing T cells but failed to enhance antibody synthesis and to induce arthritis in C57BL/6 or BALB/c mice immunized with collagen in oil. These results indicate that the induction (by IL-12) of a strong collagen-specific T-cell response alone is not sufficient to trigger arthritis. Attempts to show a role for endogenous IL-12 in DBA/1 mice immunized with collagen with mycobacteria as adjuvant gave no reliable results. Whereas anti-IL-12 treatment delayed the onset and ameliorated the disease in some experiments, it failed to do so in other experiments, or, control reagents also had some effect. A slight inhibition of collagen-specific IgG2a synthesis was observed in most experiments in the sera of anti-IL-12-treated mice. Taken together, the results show that exogenous IL-12 can promote arthritis via its direct effect on T cells and its effect on antibody production, which is at least in part IFN-gamma-dependent. On the other hand, whether or not endogenous IL-12 is involved in the adjuvant effect of mycobacteria needs further clarification.

Adjuvants, Immunologic↗
PubMed1996

Th1 development of naive CD4+ T cells is inhibited by co-activation with anti-CD4 monoclonal antibodies.

Co-activation of CD4+ T cells by anti-CD4 mAb strongly enhances the proliferation of these T cells. We have analyzed the influence of CD4-mediated co-activation on Th cell differentiation. Our data demonstrate that activation of high density (HD)-CD4+ T cells by immobilized anti-CD3 mAb in combination with immobilized anti-CD4 mAb led to a strong inhibition of Th1 differentiation and to a variable but significant induction of Th2 development. Priming of highly enriched Mel-14highCD4+ T cells in the presence of anti-CD4 mAb also resulted in a pronounced suppression of secondary IFN-gamma production, indicating that the Th1 development of naive CD4+ T cells is inhibited by co-activation via CD4. In contrast to HD-CD4+ T cells, CD4-induced costimulation of MEL-14highCD4+ T cells did not result in a primary and secondary IL-4 production. Hence, these results suggest that a MEL-14low population within the HD-CD4+ T cell fraction was the source of the endogenous IL-4 and imply, in addition, that co-activation via CD4 inhibits the development of Th1 cells from naive CD4+ T cells independently from endogenous IL-4. This assumption is further corroborated by the fact that neither the application of neutralizing anti-IL-4 mAb nor the use of T cells from IL-4 knockout mice could prevent CD4-mediated inhibition of Th1 development. The Th1-inhibiting effect of anti-CD4 mAb could not be reversed by the application of the Th1 inducer IL-12. On the contrary, the secondary IL-4 production of HD-CD4+ T cells as an indicator of Th2 differentiation, which was promoted by anti-CD4 mAb, was enhanced even in the presence of IL-12. Therefore, our results suggest that co-activation of naive CD4+ T cells by anti-CD4 mAb directly and selectively inhibits Th1 differentiation of naive dense CD4+ T cells.

Animals↗
PubMed1996

High doses of interleukin-12 inhibit the development of joint disease in DBA/1 mice immunized with type II collagen in complete Freund's adjuvant.

Collagen-induced arthritis (CIA) is an (autoimmune) joint disease readily elicited in DBA/1 mice by immunization with type II collagen (CII) emulsified with complete Freund's adjuvant. It is a destructive arthritis involving about 50% of the limbs and occurs with an incidence of 70% to 100%. In this study we evaluated the effect of mouse recombinant interleukin-12 (mrIL-12) on CIA. Administration of mrIL-12 at high doses (1 micrograms/mouse, daily) for 2 or 3 weeks delayed the onset and reduced the incidence of CIA. Furthermore, the severity of CIA was much milder and in most cases restricted to single digits of the paws. Short-term administration of high doses of IL-12 exerted some, but less pronounced, disease-suppressing effect. In contrast, 10-fold lower doses of IL-12 given during the first 3 weeks, or high doses of IL-12 administered therapeutically proved to be ineffective. Only those regimens of IL-12 treatment that ameliorated CIA were associated with a down-regulation of the CII-specific antibody response. A strong inhibition of CII-specific IgG1 antibodies (10- to 20-fold) and a moderately (2- to 6-fold) suppressed IgG2b response was observed, whereas the level of CII-specific IgG2a antibodies remained high. Taken together, the results indicate that some initial events in the induction of CIA in DBA/1 mice injected with CII emulsified with CFA are suppressed by treatment with high doses of IL-12.

Animals↗
PubMed1996

IL-12 promotes cellular but not humoral type II collagen-specific Th 1-type responses in C57BL/6 and B10.Q mice and fails to induce arthritis.

DBA/1 (H-2q) and C57BL/6 (H-2b) mice develop an intermediate immune responses when immunized with chicken type II collagen (CII) emulsified with incomplete Freund's adjuvant (IFA). Only a few animals develop a mild form of arthritis. As reported before and confirmed herein, administration of IL-12 to DBA/1 mice immunized with CII in IFA strongly enhances the cellular and humoral (auto)immune response to CII and induces severe destructive joint disease with an incidence of 80-100%. In contrast, the same treatment did not promote joint disease in C57BL/6 mice. Characterization of the IL-12 effect on the CII-specific immune response of C57BL/6 mice revealed that IL-12 promoted the development of CII-specific T cells producing IFN-gamma in DBA/1 and C57BL/6 mice equally well. However, whereas treatment with IL-12 in DBA/1 mice strongly up-regulated the synthesis of CII-specific antibodies, especially of the IgG2a and IgG2b subclasses, it rather slightly down-regulated the CII-specific IgG2a and IgG2b synthesis in C57BL/6 mice. This may indicate that the effect of IL-12 on the CII-specific antibody synthesis is of crucial importance in the pathogenesis of type II collagen-induced arthritis (CIA). The failure of IL-12 to up-regulate IgG2a and IgG2b synthesis in C57BL/6 mice is specific for CII as antigen and not a general property of this strain because the keyhole limpet hemacyanin-specific antibody response is up-regulated by IL-12 in C57BL/6 mice. Furthermore, it is not the H-2b haplotype of C57BL/6 mice but rather the genetic background (DBA/1 versus BL/6 or BL/10) that limits the effect of IL-12 on the CII-specific antibody response because IL-12 treatment of CII-immunized B10.Q (H-2q) mice also failed to induce arthritis and to enhance CII-specific IgG2a and IgG2b synthesis. However, as in the two other strains, injection of IL-12 promoted the development of splenic T cells producing IFN-gamma upon activation with CII. These results indicate that an enhancement of the cellular and humoral anti-CII response by IL-12 is required for inducing arthritis.

Animals↗
PubMed1995

IL-12 as mediator and adjuvant for the induction of contact sensitivity in vivo.

To determine whether IL-12 serves as a regulator of contact sensitivity reactions, mice were painted with either 1.0% trinitrochlorobenzene or 0.5% dinitrofluorobenzene on abdominal skin. At various time points thereafter, regional lymph nodes or spleens were prepared for RNA extraction, and the signals for IL-12 p35 and p40 chain were sought by quantitative reverse transcriptase-PCR. Time course analysis showed a constitutive expression of p35 chain mRNA signals throughout the experiment (0 to 72 h), whereas the signal for the p40 chain was transiently induced in lymph node and spleen cells after 12 to 14 h. Cellular depletion experiments and double label in situ hybridization studies showed that dendritic cells were sources for a major part of the p40 chain message. The presence of functional IL-12 in culture supernatants was indirectly assessed by addition of anti-IL-12 antiserum and analysis of IFN-gamma production. Significant amounts of IFN-gamma could only be detected in supernatants of allergen-treated animals. Addition of anti-IL-12 antiserum inhibited IFN-gamma production by about 55%. In a further attempt to assess the role of IL-12 in contact sensitivity, anti-IL-12 antiserum was injected i.p. into mice, and ear swelling responses were assessed following challenge. Injection of anti-IL-12 antiserum significantly reduced ear swelling responses by 85%. Thus anti-IL-12 treatment almost completely prevented sensitization. To assess whether IL-12 would be able to overcome in vivo tolerance, UV-tolerized animals were treated with i.p. IL-12 in a contact allergy system. Treatment of mice with IL-12 not only prevented tolerance induction, but was able to reverse UV-induced tolerance. In aggregate, our data point to an important role for IL-12 as a mediator and adjuvant for the induction of contact sensitivity in vivo.

Adjuvants, Immunologic↗
PubMed1995

Opposing effects of TGF-beta 2 on the Th1 cell development of naive CD4+ T cells isolated from different mouse strains.

The development of naive dense CD4+ T cells from different mouse strains toward Th1 cells, as monitored by measuring secondary IFN-gamma production, was affected by TGF-beta 2 in a differential way. Th1 cell development of naive CD4+ T cells from strains C57Bl/6, BALB/c, and NMRI primed by immobilized anti-CD3 mAb was strongly inhibited in the presence of TGF-beta 2. Even when the Th1 cell-inducer IL-12 was added, the same effect of TGF-beta 2 was observed. In contrast, Th1 development was substantially promoted by TGF-beta 2 with T cells from C3H/He and CBA/J mice. Further analyses using CD4+ T cells from (C57Bl/6xCBA/J)F1 hybrids or DBA/1 mice showed that Th1 development was inhibited by TGF-beta 2 if the T cells were activated by anti-CD3 mAb, but it was enhanced upon costimulation with anti-CD28 mAb. Determination of primary IL-2 production revealed that T cells from (C57Bl/6xCBA/J)F1 and DBA/1 mice produced low amounts of IL-2 following stimulation by anti-CD3 mAb alone and comparatively high amounts after coactivation by anti-CD28 mAb. In the presence of TGF-beta 2, the production of IL-2 was completely suppressed if such T cells were activated solely by anti-CD3 mAb, but it was only partially inhibited after costimulation by anti-CD28 mAb. Furthermore, TGF-beta 2-promoted Th1 development of such T cells was strongly inhibited after neutralization of endogenously produced IL-2 and completely restored by the addition of human IL-2. Thus, our results indicate that the TGF-beta 2-mediated stimulation of Th1 cell development requires the presence of relatively high concentrations of IL-2. Therefore, the opposing effect of TGF-beta 2 on the Th1 cell development of naive CD4+ T cells from different mouse strains appears to be the result of the variable potency of the respective CD4+ T cells to produce IL-2 in the presence of TGF-beta 2.

Animals↗
PubMed1995

Administration of interleukin 12 in combination with type II collagen induces severe arthritis in DBA/1 mice.

The induction of arthritis in DBA/1 mice usually requires immunization with the antigen type II collagen emulsified with Mycobacterium tuberculosis in oil. Here we describe that interleukin 12 (IL-12) can replace mycobacteria and cause severe arthritis of DBA/1 mice when administered in combination with type II collagen. Immunization of DBA/1 mice with type II collagen emulsified in oil alone resulted in a weak immune response, and only a few animals (10-30%) developed arthritis. Administration of IL-12 for 5 days simultaneously with each immunization strongly enhanced the anti-type II collagen immune response. Collagen-specific interferon gamma (IFN-gamma) synthesis by ex vivo activated spleen cells was enhanced 3- to 10-fold. IFN-gamma was almost completely produced by CD4+ T cells. Furthermore, the production of collagen-specific IgG2a and IgG2b antibodies was upregulated 10- to 100-fold. As a consequence, the incidence of arthritis in the group of mice immunized with collagen plus IL-12 was very high (80-100%). The developing arthritis was severe, involving approximately 50% of all limbs with strongly increased footpad thickness in most cases. Furthermore, histological examination revealed massive, mainly polymorphonuclear cell infiltration, synovial hyperplasia, cartilage and bone destruction, as well as new bone formation. In many cases, this resulted in the complete loss of joint structure. Neutralization of IFN-gamma in vivo prevented the development of arthritis in collagen-immunized and IL-12-treated mice. In conclusion, our data show that in vivo administered IL-12 can profoundly upregulate a T helper I-type autoimmune response, resulting in severe joint disease in DBA/1 mice.

Animals↗
PubMed1995

Interleukin-12 profoundly up-regulates the synthesis of antigen-specific complement-fixing IgG2a, IgG2b and IgG3 antibody subclasses in vivo.

The influence of the cytokine interleukin-12 (IL-12) on humoral immune responses was studied in vivo. CBA/J mice immunized with protein antigens (keyhole limpet hemocyanin, phospholipase A2) adsorbed to aluminum hydroxide (Alum) develop a Th2-like immune response characterized by the production of large amounts of IgG1 as well as some IgE but little IgG2a, IgG2b and IgG3 antibodies. IL-12 is a cytokine that promotes the development and the activation of Th1 cells. Th1 cells are involved in the induction of cellular immunity, which is characterized by low or absent antibody production. On the other hand, some Th1-like immune responses are associated with a strong antibody production of the IgG2a, IgG2b and IgG3 subclasses. Thus, we investigated whether treatment with IL-12 would down-regulate the humoral immune response or stimulate antibody production of the IgG2a, IgG2b and IgG3 subclasses. We observed that: 1) administration of IL-12 to mice together with protein antigens adsorbed to Alum strongly enhanced the humoral immune response by increasing the synthesis of antigen-specific antibodies of the IgG2a, IgG2b and IgG3 subclasses 10- to 1000-fold. The synthesis of IgG1 was not or only slightly (2-5-fold) enhanced, whereas that of the IgE isotype was suppressed. 2) These effects of IL-12 were observed when high (10 micrograms, 100 micrograms) or low doses (0.1 microgram) of antigen were used for immunization. 3) Titration of IL-12 in vitro revealed that IgG2a is strongly up-regulated over a wide dose range of IL-12 (10 to 1000 ng/day). 4) The effects of IL-12 in vivo are at least partially interferon (IFN)-gamma-dependent because an anti-IFN-gamma mAb in combination with IL-12 prevented most of the enhanced IgG2a production. 5) Mice receiving IL-12 showed a strong up-regulation of IFN-gamma but no inhibition of IL-5 synthesis by spleen cells activated ex vivo with antigen. These results suggest that IL-12 is a potent adjuvant for enhancing humoral immunity to protein antigens adsorbed to Alum, primarily by inducing the synthesis of the complement-fixing IgG subclasses 2a, 2b and 3.

Aluminum Hydroxide↗
PubMed1995

The role of IL-12 in the induction of organ-specific autoimmune diseases.

The concept that T cells are subdivided into T helper 1 (Th1) and Th2 subsets was recently extended to suggest that Th1 cells contribute to the pathogenesis of several organ-specific autoimmune diseases, whereas Th2 cells inhibit disease development. Here, Sylvie Trembleau and colleagues examine the role of interleukin 12 (IL-12), a key cytokine guiding the development of Th1 cells, in the induction of autoimmune diseases, and discuss potential immunointervention strategies based on administration of IL-12 antagonists.

Animals↗