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Interferon gamma (IFN-gamma) is necessary for the genesis of acetylcholine receptor-induced clinical experimental autoimmune myasthenia gravis in mice.

Balasa B, Deng C, Lee J, Bradley LM, Dalton DK, Christadoss P, Sarvetnick N - J. Exp. Med. (1997)

Bottom Line: However, the role of cytokines in the pathogenesis of EAMG is not clear.Because EAMG is an antibody-mediated disease, it is of the prevailing notion that Th2 but not Th1 cytokines play a role in the pathogenesis of this disease.The resistance of IFN-gko mice was associated with greatly reduced levels of circulating anti-AChR antibody levels compared with those in the WT mice.

View Article: PubMed Central - PubMed

Affiliation: The Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.

ABSTRACT
Experimental autoimmune myasthenia gravis (EAMG) is an animal model of human myasthenia gravis (MG). In mice, EAMG is induced by immunization with Torpedo californica acetylcholine receptor (AChR) in complete Freund's adjuvant (CFA). However, the role of cytokines in the pathogenesis of EAMG is not clear. Because EAMG is an antibody-mediated disease, it is of the prevailing notion that Th2 but not Th1 cytokines play a role in the pathogenesis of this disease. To test the hypothesis that the Th1 cytokine, interferon (IFN)-gamma, plays a role in the development of EAMG, we immunized IFN-gamma knockout (IFN-gko) (-/-) mice and wild-type (WT) (+/+) mice of H-2(b) haplotype with AChR in CFA. We observed that AChR-primed lymph node cells from IFN-gko mice proliferated normally to AChR and to its dominant pathogenic alpha146-162 sequence when compared with these cells from the WT mice. However, the IFN-gko mice had no signs of muscle weakness and remained resistant to clinical EAMG at a time when the WT mice exhibited severe muscle weakness and some died. The resistance of IFN-gko mice was associated with greatly reduced levels of circulating anti-AChR antibody levels compared with those in the WT mice. Comparatively, immune sera from IFN-gko mice showed a dramatic reduction in mouse AChR-specific IgG1 and IgG2a antibodies. However, keyhole limpet hemocyanin (KLH)-priming of IFN-gko mice readily elicited both T cell and antibody responses, suggesting that IFN-gamma regulates the humoral immune response distinctly to self (AChR) versus foreign (KLH) antigens. We conclude that IFN-gamma is required for the generation of a pathogenic anti-AChR humoral immune response and for conferring susceptibility of mice to clinical EAMG.

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(A) Effect of IFN-γ gene disruption on in vitro lymphocyte  proliferation in response to AChR (10 μg/ml) and control antigen  (OVA; 20 μg/ml) on day 5 after immunization with 20 μg AChR in  CFA. Results were expressed as a stimulation index. Background cpm in  the absence of antigen for C57BL/6, WT, and IFN-gko mice are as follows: 1,019, 1,039, 3,443. (B). Effect of IFN-γ gene disruption on in  vitro lymphocyte proliferation in response to KLH (50 μg/ml) and control antigen (OVA; 20 μg/ml) on day 5 after immunization with 100 μg  KLH in CFA. Background cpm in the absence of antigen for C57BL/6,  WT, and IFN-gko mice are as follows: 15,184, 14,223, 17,095.
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Figure 1: (A) Effect of IFN-γ gene disruption on in vitro lymphocyte proliferation in response to AChR (10 μg/ml) and control antigen (OVA; 20 μg/ml) on day 5 after immunization with 20 μg AChR in CFA. Results were expressed as a stimulation index. Background cpm in the absence of antigen for C57BL/6, WT, and IFN-gko mice are as follows: 1,019, 1,039, 3,443. (B). Effect of IFN-γ gene disruption on in vitro lymphocyte proliferation in response to KLH (50 μg/ml) and control antigen (OVA; 20 μg/ml) on day 5 after immunization with 100 μg KLH in CFA. Background cpm in the absence of antigen for C57BL/6, WT, and IFN-gko mice are as follows: 15,184, 14,223, 17,095.

Mentions: CD4+ T cells reactive to AChR and its dominant α146–162 peptide are pivotal in the ability of B cells to generate pathogenic anti-AChR Abs (3, 10–12). To address whether the resistance of IFN-gko (−/−) mice results from their inability to evoke T cell responses to AChR and its α146–162 peptide, we immunized WT (+/+) and IFN-gko (−/−) mice with 20 μg of AChR in CFA. 5 d later, proliferation of their draining LNC was assayed. As illustrated in Fig. 1 A, the AChR-primed LNC from C57BL/6 and WT (+/+) mice proliferated strongly in response to AChR, as expected. LNC from IFN-gko (−/−) mice also proliferated significantly against the AChR. Significant proliferative responses (SI = 25.5 ± 1.8) to α146–162 peptide of AChR were also observed with AChR-primed LNC from IFN-gko mice (data not shown). A similar magnitude of proliferative responses were observed with LNC from IFN-gko and control group mice after 14 d of AChR priming (data not shown). Interestingly, when the mice were immunized with KLH, the intensity of the proliferative response of draining LNC from IFN-gko (−/−) and WT (+/+) mice appear similar (Fig. 1 B). Further examination of IFN-γ levels in the culture supernatants collected 48 h after an in vitro boost with AChR revealed the presence of IFN-γ in cultured LNC of the C57BL/6 and WT (+/+) mice but not of the IFN-gko (−/−) mice (data not shown).


Interferon gamma (IFN-gamma) is necessary for the genesis of acetylcholine receptor-induced clinical experimental autoimmune myasthenia gravis in mice.

Balasa B, Deng C, Lee J, Bradley LM, Dalton DK, Christadoss P, Sarvetnick N - J. Exp. Med. (1997)

(A) Effect of IFN-γ gene disruption on in vitro lymphocyte  proliferation in response to AChR (10 μg/ml) and control antigen  (OVA; 20 μg/ml) on day 5 after immunization with 20 μg AChR in  CFA. Results were expressed as a stimulation index. Background cpm in  the absence of antigen for C57BL/6, WT, and IFN-gko mice are as follows: 1,019, 1,039, 3,443. (B). Effect of IFN-γ gene disruption on in  vitro lymphocyte proliferation in response to KLH (50 μg/ml) and control antigen (OVA; 20 μg/ml) on day 5 after immunization with 100 μg  KLH in CFA. Background cpm in the absence of antigen for C57BL/6,  WT, and IFN-gko mice are as follows: 15,184, 14,223, 17,095.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC2198999&req=5

Figure 1: (A) Effect of IFN-γ gene disruption on in vitro lymphocyte proliferation in response to AChR (10 μg/ml) and control antigen (OVA; 20 μg/ml) on day 5 after immunization with 20 μg AChR in CFA. Results were expressed as a stimulation index. Background cpm in the absence of antigen for C57BL/6, WT, and IFN-gko mice are as follows: 1,019, 1,039, 3,443. (B). Effect of IFN-γ gene disruption on in vitro lymphocyte proliferation in response to KLH (50 μg/ml) and control antigen (OVA; 20 μg/ml) on day 5 after immunization with 100 μg KLH in CFA. Background cpm in the absence of antigen for C57BL/6, WT, and IFN-gko mice are as follows: 15,184, 14,223, 17,095.
Mentions: CD4+ T cells reactive to AChR and its dominant α146–162 peptide are pivotal in the ability of B cells to generate pathogenic anti-AChR Abs (3, 10–12). To address whether the resistance of IFN-gko (−/−) mice results from their inability to evoke T cell responses to AChR and its α146–162 peptide, we immunized WT (+/+) and IFN-gko (−/−) mice with 20 μg of AChR in CFA. 5 d later, proliferation of their draining LNC was assayed. As illustrated in Fig. 1 A, the AChR-primed LNC from C57BL/6 and WT (+/+) mice proliferated strongly in response to AChR, as expected. LNC from IFN-gko (−/−) mice also proliferated significantly against the AChR. Significant proliferative responses (SI = 25.5 ± 1.8) to α146–162 peptide of AChR were also observed with AChR-primed LNC from IFN-gko mice (data not shown). A similar magnitude of proliferative responses were observed with LNC from IFN-gko and control group mice after 14 d of AChR priming (data not shown). Interestingly, when the mice were immunized with KLH, the intensity of the proliferative response of draining LNC from IFN-gko (−/−) and WT (+/+) mice appear similar (Fig. 1 B). Further examination of IFN-γ levels in the culture supernatants collected 48 h after an in vitro boost with AChR revealed the presence of IFN-γ in cultured LNC of the C57BL/6 and WT (+/+) mice but not of the IFN-gko (−/−) mice (data not shown).

Bottom Line: However, the role of cytokines in the pathogenesis of EAMG is not clear.Because EAMG is an antibody-mediated disease, it is of the prevailing notion that Th2 but not Th1 cytokines play a role in the pathogenesis of this disease.The resistance of IFN-gko mice was associated with greatly reduced levels of circulating anti-AChR antibody levels compared with those in the WT mice.

View Article: PubMed Central - PubMed

Affiliation: The Department of Immunology, The Scripps Research Institute, La Jolla, California 92037, USA.

ABSTRACT
Experimental autoimmune myasthenia gravis (EAMG) is an animal model of human myasthenia gravis (MG). In mice, EAMG is induced by immunization with Torpedo californica acetylcholine receptor (AChR) in complete Freund's adjuvant (CFA). However, the role of cytokines in the pathogenesis of EAMG is not clear. Because EAMG is an antibody-mediated disease, it is of the prevailing notion that Th2 but not Th1 cytokines play a role in the pathogenesis of this disease. To test the hypothesis that the Th1 cytokine, interferon (IFN)-gamma, plays a role in the development of EAMG, we immunized IFN-gamma knockout (IFN-gko) (-/-) mice and wild-type (WT) (+/+) mice of H-2(b) haplotype with AChR in CFA. We observed that AChR-primed lymph node cells from IFN-gko mice proliferated normally to AChR and to its dominant pathogenic alpha146-162 sequence when compared with these cells from the WT mice. However, the IFN-gko mice had no signs of muscle weakness and remained resistant to clinical EAMG at a time when the WT mice exhibited severe muscle weakness and some died. The resistance of IFN-gko mice was associated with greatly reduced levels of circulating anti-AChR antibody levels compared with those in the WT mice. Comparatively, immune sera from IFN-gko mice showed a dramatic reduction in mouse AChR-specific IgG1 and IgG2a antibodies. However, keyhole limpet hemocyanin (KLH)-priming of IFN-gko mice readily elicited both T cell and antibody responses, suggesting that IFN-gamma regulates the humoral immune response distinctly to self (AChR) versus foreign (KLH) antigens. We conclude that IFN-gamma is required for the generation of a pathogenic anti-AChR humoral immune response and for conferring susceptibility of mice to clinical EAMG.

Show MeSH
Related in: MedlinePlus