Treatment Of Immunized Mice Research Articles

OR26-03 Treatment With Linsitinib, An IGF-1 Receptor Inhibitor, Prevents Disease Development And Progression In An Experimental Model Of Thyroid Eye Disease

Abstract Disclosure: A. Gulbins: Grant Recipient; Self; Sling therapeutics, Inc. M. Horstmann: Grant Recipient; Self; Sling therapeutics, Inc. A. Daser: None. U. Flögel: None. M. Oeverhaus: Grant Recipient; Self; Sling therapeutics, Inc. B.E. Nikolaos: None. J.P. Banga: None. G. Krause: None. G.D. Hammer: Research Investigator; Self; Sling therapeutics, Inc. A.G. Spencer: Research Investigator; Self; Sling therapeutics, Inc. R. Zeidan: Research Investigator; Self; Sling therapeutics, Inc. A. Eckstein: Grant Recipient; Self; Sling therapeutics, Inc. S. Philipp: Grant Recipient; Self; Sling therapeutics, Inc. G. Görtz: Grant Recipient; Self; Sling therapeutics, Inc. Study objective: We investigated the effect of linsitinib, a small molecule inhibitor of the Insulin like growth factor 1 receptor (IGF-1R), on Graves’ disease and thyroid eye disease. Graves‘ disease (GD), also known as “Basedow's disease“, is the most common cause for hyperthyroidism, typically presenting in patients between 40-60 years. GD is an autoimmune condition of the thyroid which is caused by autoantibodies against the thyroid stimulating hormone receptor (TSHR). Thyroid eye disease (TED) is the most common extra thyroidal manifestation of GD and occurs in about 50% of the clinical cases. Methods: To induce Graves’ Disease in mice we immunized mice 3-times with a plasmid encoding for the A-subunit of the TSHR. During each active (early) and chronic (late) states of the autoimmune disease, linsitinib was administered orally for four weeks. Endocrine orbitopathy and inflammation were determined by histology and MRI. Results: As seen in the histology, linsitinib prevented autoimmune hyperthyroidism, morphological changes, formation of brown adipose tissue in the orbita and orbital T-cell and macrophage infiltration into the orbit in the active state as well as the chronic phase. To evaluate the effect of linsitinib during the course of therapy, living mice were examined via MRI. A distinctive migration of immune cells in the orbit with consecutive inflammation can be seen in the TSHR-immunized group, which is completely blocked by treatment with linsitinib. In addition, the orbital inflammation was partnered with the onset of muscle edema and formation of brown adipose tissue in TSHR-immunized mice, effects that were abrogated upon application of linsitinib. Conclusion: In summary, we demonstrate the development of GD and TED in a mouse model upon immunization against the TSHR. The IGF-1R antagonist linsitinib blocks the development of the local pathologies of GD and TED in an early and late phase of the autoimmune disorder and also prevents development of the autoimmune response. We show that treatment of immunized mice with linsitinib after disease onset significantly limited the severity of the disease, indicating the clinical significance of the findings and providing a path to therapeutic intervention of Graves’ Disease. Our data support the use of linsitinib as a novel first line treatment of thyroid eye disease. Presentation: Saturday, June 17, 2023

THE EFFECT OF OF POLY(ADP-RIBOSE) POLYMERASE INHIBITOR 4-HYDROXY-QUINAZOLINE ON DEATH OF IMMUNE CELLS UNDER IMMUNE COMPLEX-MEDIATED INJURY IN MICE

The influence of poly(ADP-ribose) polymerase (PARP) in- hibitor 4-hydroxyquinazoline (4-HQ) on the level of DNA damage and on the death of thymic and lymph node cells in mouse model of immune complex injury was investigated to reveal its possible cytoprotective effect. As shown by comet assay, DNA damage index of immune cells was increased 4,0 times in mice with immune complex-mediated pathology induced by a long-term immunization of CBA mice with bovine serum albumin (BSA), P<0,001. The percentage of thymic cells with strong DNA damage was increased to 77% under immunization (compared to 1,5% in control mice) and the percentage of such cells from lymph nodes was increased to 80% (compared to 0% in control), in both cases P< 0,001. Genotoxic stress was reduced by treatment of immunized mice with 4-HQ: the percentage of lymphocytes with strong DNA damage was significantly decreased that promoted increase in the amount of cells having intact DNA. PARP inhibition exerted a strong cytoprotective effect: viability of thymus and lymph node cells was increased mainly due to reduced level of necrosis. So, our results suggest that PARP may be involved in thymic and lymph node cell damage in immune complex mediated pathology and give evidence that inhibition of this enzyme may constitute a perspective target in immune complex diseases prevention and therapy.

Anti-interleukin-6 receptor antibody prevents systemic bone mass loss via reducing the number of osteoclast precursors in bone marrow in a collagen-induced arthritis model

Systemic bone loss is a hallmark of rheumatoid arthritis (RA). Inflammatory cytokines such as interleukin (IL)-6 promote bone resorption by osteoclasts. Sphingosine-1-phosphate (S1P) controls the migration of osteoclast precursor cells (OCPs) between the blood and bone marrow, in part via S1P receptors (S1PR1 and S1PR2) expressed on the surface of OCPs. OCPs (CD11b(+) Gr-1(low+med) ) isolated from bone marrow of DBA/1J mice were stimulated with IL-6. S1P-directed chemotaxis of OCPs was evaluated using a transwell plate. mRNA expression of S1PR1 and S1PR2 was measured. DBA/1J mice were immunized with bovine type II collagen (days 0 and 21) and anti-mouse IL-6 receptor antibody (MR16-1) was administered on days 0 and/or 21. Trabecular bone volume was analysed using micro-computed tomography. The percentage of OCPs in tibial bone marrow and S1PR1 and S1PR2 mRNA expression in OCPs were measured. IL-6 stimulation significantly decreased S1P-directed chemotaxis of OCPs. IL-6 induced S1PR2 mRNA expression, but not S1PR1 mRNA expression, in OCPs. Bone volume was significantly lower in arthritic mice than in non-arthritic control mice on day 35. Treatment of immunized mice with MR16-1 significantly inhibited bone loss. In MR16-1-treated mice, the percentage of OCPs and expression of S1PR2 mRNA was each decreased compared with arthritic mice on day 14, but not on day 35. IL-6 increased the number of OCPs in tibial bone marrow via up-regulating S1PR2, thus playing a crucial role in systemic bone loss induced by inflammation.

FRI0048 Interleukin-6 increases the number of osteoclast precursors in femur bone marrow via up-regulation of sphingosine-1-phosphate receptor 2 in inflammatory arthritic mice

BackgroundRheumatoid arthritis (RA) is associated with an increased risk of osteoporosis and fractures. A number of factors such as menopause, glucocorticoid use, and high RA disease activity are associated with...

Granulocyte expansion and mobilization following EAE induction is correlated with G-CSF production. (44.43)

Abstract Experimental autoimmune encephalomyelitis (EAE) is a murine model of neuroinflammatory demyelination that is frequently used as a model for multiple sclerosis (MS). EAE is induced mice by immunization with a myelin epitope and adjuvants. We have previously shown that granulocytes are critical for blood-brain-barrier (BBB) breakdown and clinical disease in EAE. In the current study we investigated the pathways by which granulocytes are regulated during EAE. We found that granulocytes expand in the bone marrow and the bloodstream by day 3 p.i., which was preceded by a spike in systemic levels of G-CSF, a granulocyte growth and mobilization factor. Administration of Bordetella pertussis toxin (BPT) is required for the clinical manifestation of disease in our model. Interestingly, sustained expression of G-CSF and accumulation of circulating granulocytes only occurred in mice given BPT. Treatment of immunized mice with an antagonistic G-CSF receptor-Fc fusion protein prevented clinical EAE. We postulate that induction of G-CSF drives the expansion and mobilization of bone marrow-derived granulocytes that ultimately mediate BBB breakdown and subsequent CNS infiltration by leukocytes. Consistent with our findings, individuals with MS experienced severe exacerbations upon the administration of recombinant G-CSF following bone marrow transplantation. Furthermore, we suggest granulocyte growth and mobilization factors as novel therapeutic targets in autoimmune demyelinating disease.

Increasing CNS Noradrenaline Reduces EAE Severity

The endogenous neurotransmitter noradrenaline (NA) is known to exert potent anti-inflammatory effects in glial cells, as well as provide neuroprotection against excitatory and inflammatory stimuli. These properties raise the possibility that increasing levels of NA in the central nervous system (CNS) could provide benefit in neurological diseases and conditions containing an inflammatory component. In the current study, we tested this possibility by examining the consequences of selectively modulating CNS NA levels on the development of clinical signs in experimental autoimmune encephalomyelitis (EAE). In mice immunized with myelin oligodendrocyte glycoprotein peptide to develop a chronic disease, pretreatment to selectively deplete CNS NA levels exacerbated clinical scores. Elevation of NA levels using the selective NA reuptake inhibitor atomoxetine did not affect clinical scores, while treatment of immunized mice with the synthetic NA precursor L-threo-3,4-dihydroxyphenylserine (L-DOPS) prevented further worsening. In contrast, treatment of mice with a combination of atomoxetine and L-DOPS led to significant improvement in clinical scores as compared to the control group. The combined treatment reduced astrocyte activation in the molecular layer of the cerebellum as assessed by staining for glial fibrillary protein but did not affect Th1 or Th17 type cytokine production from splenic T cells. These data suggest that selective elevation of CNS NA levels could provide benefit in EAE and multiple sclerosis without influencing peripheral immune responses.

Roles for CD40, B7 and major histocompatibility complex in induction of enhanced immunity by cryptococcal polysaccharide-pulsed antigen-presenting cells.

Immunization of mice with activated antigen-presenting cells (APC) pulsed ex vivo with cryptococcal capsular polysaccharide, a glucuronoxylomannan (GXM-APC) results in prolongation of survival and delayed-type hypersensitivity (DTH) responsiveness following infection with Cryptococcus neoformans (NU-2). GXM-APC has both non-specific and GXM-specific effects that influence the immune responses that develop in mice after infection with NU-2. Type 1 cytokine responses are augmented after immunization with APC alone, while GXM must be present for the vaccine to influence survival and DTH reactions. This investigation evaluated the role that major histocompatibility complex (MHC) and co-stimulatory molecules play in the non-specific and GXM-specific responses induced by GXM-APC. APC from CD40 knockout mice were as effective as wild-type APC for the induction of non-specific and GXM-specific responses. Blocking activity of B7-1 and B7-2 by treatment of immunized mice with monoclonal antibodies specific for these molecules just before and for 6 days following GXM-APC immunization decreased the splenic interferon-gamma response of mice subsequently infected with NU-2, but only in mice that were treated with both antibodies. These antibody treatments had no effect on DTH reactivity in similarly treated animals. MHC class I molecules were not involved in the antigen non-specific or GXM-specific activities of the vaccine. MHC class II molecules were not required for augmentation of type 1 cytokine responses but were needed for induction of the GXM-specific response that regulates the expression of DTH reactivity. This investigation has shown that an MHC class II-restricted, GXM-specific response is responsible for altering DTH responsiveness which is the correlate of immunity in this model.

Roles of CD4(+) T cells and gamma interferon in protective immunity against Babesia microti infection in mice.

Babesia microti produces a self-limiting infection in mice, and recovered mice are resistant to reinfection. In the present study, the role of T cells in protective immunity against challenge infection was examined. BALB/c mice which recovered from primary infection showed strong protective immunity against challenge infection. In contrast, nude mice which failed to control the primary infection and were cured with an antibabesial drug did not show protection against challenge infection. Treatment of immune mice with anti-CD4 monoclonal antibody (MAb) diminished the protective immunity against challenge infection, but treatment with anti-CD8 MAb had no effect on the protection. Transfer of CD4(+) T-cell-depleted spleen cells resulted in higher parasitemia than transfer of CD8(+) T-cell-depleted spleen cells. A high level of gamma interferon (IFN-gamma), which was produced by CD4(+) T cells, was observed for the culture supernatant of spleen cells from immune mice, and treatment of immune mice with anti-IFN-gamma MAb partially reduced the protection. Moreover, no protection against challenge infection was found in IFN-gamma-deficient mice. On the other hand, treatment of immune mice with MAbs against interleukin-2 (IL-2), IL-4, or tumor necrosis factor alpha did not affect protective immunity. These results suggest essential requirements for CD4(+) T cells and IFN-gamma in protective immunity against challenge infection with B. microti.

IL-12 eliminates the Th-2 dependent protective immune response of mice to larval Strongyloides stercoralis.

The goal of the present study was to determine if immune-mediated killing of S. stercoralis L3 in mice could be modulated by shifting from a Th-2 to a Th-1 type immune response. L3 killing in immunized mice was ablated in CD4+ T cell-depleted animals, but not in CD8+ T cell-depleted or beta 2-microglobulin-deficient mice. Treatment of immunized mice with IL-4 or IL-5 neutralizing MoAb significantly reduced the protective effects of vaccination against S. stercoralis, while protective immunity was unimpaired in IFN-gamma knockout mice. Recombinant IL-12 was administered to infected mice to switch the immune response from a Th-2 to a Th-1 type response. Protective immunity was ablated in immunized mice that received IL-12 therapy. Eosinophil numbers, eosinophil peroxidase levels, and parasite-specific IgG1 levels were lowered in IL-12 treated immunized animals, and parasite-specific IgG2a levels were increased in these animals. The data indicate that eosinophils are important as mediators of larval killing, and that the establishment of Th-2 type immunity results in killing of infective S. stercoralis L3, while a shift to Th-1 type immunity abrogates protective responses.

Neutrophils are essential for resolution of primary and secondary infection with Listeria monocytogenes

The role for neutrophils in the resolution of primary and secondary infection with Listeria monocytogenes was studied. The results show that although control mice started to clear Listeria from their spleens and livers between days 2 and 4 of sublethal primary infection and eradicated bacteria in 2 weeks, mice given a specific granulocyte-depleting antibody (RB6-8C5) on days 4 or 6 of infection developed lethal listeriosis. Likewise, treatment of immunized mice with RB6-8C5 monoclonal antibody abolished their acquired ability to resolve a lethal challenge infection. The results demonstrate that neutrophils are necessary for the resolution of secondary and primary Listeria infection.

Protective effect of rSm28GST-specific T cells in schistosomiasis: role of gamma interferon.

Immunization with a single dose of 50 micrograms of recombinant Schistosoma mansoni 28-kDa glutathione-S-transferase (rSm28GST) was able to induce a reduction in the worm burden, the number of eggs, and the degree of hepatic fibrosis as quantified by the measurement of collagen content in the liver of S. mansoni-infected mice. No relationship was found between anti-Sm28GST immunoglobulin G and immunoglobulin A titers and the levels of protection obtained. Adoptive transfers of Sm28GST-specific total, CD4+, or CD8+ T cells reproduced the protective effect obtained with the recombinant molecule. Moreover, experiments studying in vivo T-cell depletion demonstrated that anti-CD4- or anti-CD8-treated mice showed a significant decrease in the protective effect conferred, suggesting a role of the two T-cell subpopulations in the expression of Sm28GST-mediated protection against hepatic damage. Sm28GST-specific cells produced little interleukin-4 and high levels of gamma interferon. Treatment of immunized mice with anti-gamma interferon antibody totally suppressed the Sm28GST-induced protective effect and led to the rapid death of infected animals, suggesting a role for this cytokine in the expression of the protective immunity obtained after immunization with rSm28GST.

In vivo resistance of secondary antitumor immune response to cyclophosphamide: effects on T cell subsets.

We have analyzed the effects of high doses of cyclophosphamide (Cy) on primary and secondary antitumor immune response against immunogenic (tum-) variants of Lewis lung carcinoma (3LL) treated in vitro with UV light. Normal mice and mice previously immunized with tum- clones wer inoculated i.p. with Cy (200 mg/kg body weight) and 24 h later challenged intrafootpad with tum- or parental 3LL cells. Cy treatment suppressed the primary immune response of normal animals and allowed the growth of tum- cells. In contrast, Cy-treated immune mice rejected the tumor challenge. The in vivo treatment with Cy decreased the total number of lymphoid cells in the spleens, as well as the proportion of B lymphocytes; however, it increased the percentage of both Lyt2+ and L3T4+ lymphocytes. Thus, the immunosuppressive effects of Cy on the primary antitumor response could not be attributed to elimination of major T lymphocyte subpopulations. Although the treatment of immune mice with Cy did not significantly impair their antitumor resistance, nor the proportion of Lyt2+ and L3T4+ lymphocytes in their spleens, the in vitro generation of cytotoxic T lymphocytes (CTL) was markedly reduced. After Cy treatment, the proliferative ability of spleen cells in response to interleukin-2 (IL-2) was substantially impaired. Using monoclonal antibodies to the IL-2 receptor, we found that Cy-treated T lymphocytes failed to fully express the IL-2 receptor following in vitro stimulation with irradiated tumor cells. In line with these findings, the in vitro generation of CTL was not restored by addition of recombinant IL-2 to the cultures. In vivo experiments using purified functional subsets of immune T cells showed that Lyt1+, but not Lyt2+ lymphocytes were able to transfer antitumor immunity in normal irradiated recipients. Therefore, since Ly1+ T lymphocytes were responsible for the antitumor resistance in vivo, the Cy-induced impairment of CTL generation did not affect the ability of immune mice to reject a secondary tumor challenge.

The effect of sea star coelomocyte extract on cell-mediated resistance to Listeria monocytogenes in mice.

Mice treated with sea star factor (SSF), a protein extracted from sea star coelomocytes, became highly susceptible to infection with a normally sublethal dose of Listeria monocytogenes. This was in contrast to the expected result of increased resistance originally postulated because of the macrophage-activating properties of SSF. Enhanced susceptibility was seen when SSF was given from 96 h before to 48 h after infection with Listeria. Mice pretreated with SSF failed to develop immunity to Listeria when given a dose of organisms capable of immunizing nontreated mice. Treatment of immune mice with SSF did not alter their immune status. In addition, incubation of immune lymphocytes with SSF in vitro did not alter their ability to adoptively transfer immunity to normal recipients. Immune lymphocytes treated with SSF and then incubated with anti-SSF and C did, however, lose the ability to transfer immunity. These results suggest that SSF enhances infection by binding to T lymphocytes, inhibiting their replication upon contact with Listeria antigen and thus preventing the generation of a population of sensitized lymphocytes capable of effecting anti-Listeria immunity.