Transfer of immune components from rabbit autoimmune cardiomyopathy into severe combined immunodeficiency (SCID) mice induces cardiomyopathic changes

BACKGROUND: Growing evidence suggests that autoimmune mechanism plays an important role in the pathogenesis of cardiomyopathy. The purpose of this study was to investigate whether passive transfer of IgG and/or lymphocytes from rabbits with autoimmune cardiomyopathy is able to reproduce cardiomyopathic changes in severe combined immunodeficiency (SCID) mice. METHODS AND RESULTS: SCID mice were injected intraperitoneally with IgG and/or peripheral blood lymphocytes (PBL) from either rabbits immunized with both beta1-adrenoceptor peptide and M2-muscarinic receptor peptide (beta1+M2 group) or rabbits with adjuvant (N group). Thirty five SCID mice were divided into seven groups; N-IgG, N-PBL, N-IgG & PBL, (beta1+M2)-IgG, (beta1+M2)-PBL, (beta1+M2)-IgG & PBL and control groups. Heart weight in three (beta1+M2) groups were significantly increased. All mice in three (beta1+M2) groups showed high titer of rabbit anti-beta1 adrenoceptor autoantibodies, and 4 mice in the (beta1+M2)-PBL group and 3 mice in the (beta1+M2)-IgG & PBL group showed a significant increase in titer of rabbit anti-M2-muscarinic receptor autoantibodies. Focal infiltration of inflammatory cells in the myocardium was observed in the (beta1+M2)-IgG & PBL group. In the (beta1+M2)-PBL group and (beta1+M2)-IgG & PBL group, cardiomyocyte diameters were significantly increased. Some myocytes of the (beta1+M2)-IgG & PBL group exhibited intracellular edema, clumps of Z-band and increased numbers of mitochondria by using electron microscopy. CONCLUSION: Transfer of IgG and PBL from rabbits immunized with combined beta1 and M2 peptides was able to reproduce the early stage of cardiomyopathic changes in SCID mice.     

The severe combined immunodeficient (SCID) mouse as a model for the study of autoimmune diseases.

There are no readily available in vivo models to study immune cells from humans with autoimmune diseases. SCID mice, which virtually lack both T and B lymphocytes and accept xenogeneic cells, have been used during the last 5 years to provide a milieu for lymphocytes isolated from individuals with various autoimmune diseases, or for lymphocytes from mice that have a systemic lupus erythematosus-like syndrome. Whilst human autoantibodies to organ antigens have been demonstrated in most SCID mice engrafted with human lymphocytes from the peripheral blood or the target organ, inflammation of the mouse target organ has not generally been observed. This review critically analyses experiments in this area reported so far. Some pitfalls of the SCID mouse model of human autoimmune diseases are mentioned, and future experiments to study mouse and human autoimmunity with this model are proposed.     

Induction of experimental systemic lupus erythematosus (SLE) in mice with severe combined immunodeficiency (SCID).

A model in which experimental SLE is induced in normal mice by the injection of a human anti-DNA MoAb expressing a common idiotype 16/6 Id has been established in our laboratory. In the present study we have attempted the induction of experimental SLE in mice with SCID by the transfer of lymphocytes obtained from mice with experimental SLE. Disease could not be induced by direct immunization of SCID mice with the 16/6 Id nor by transfusion of normal splenocytes and immunization with the 16/6 Id thereafter. In contrast, disease was induced in SCID mice which were transplanted with splenic lymphocytes obtained from SLE afflicted BALB/c mice. The disease was expressed by the presence of high titres of antibodies and glomerular immune complex deposits were present in the kidney sections of these mice. Mice that received spleen cells from donors with experimental SLE together with the 16/6 Id developed higher titres of autoantibodies and had, in addition to the immune complex deposits, glomerular histological pathology. The model of experimental SLE induction in SCID mice should help in the elucidation of the role of different cell types in the pathogenesis of SLE.     

CD4+ T lymphocytes injected into severe combined immunodeficient (SCID) mice lead to an inflammatory and lethal bowel disease

Transfer of 2 × 10⁵ congenic or semiallogenic purified TCRαβ⁺ CD4⁺ T cells to SCID mice leads to an infiltration of the recipient gut lamina propria and epithelium with a donor-derived CD4⁺ T cell subset which induces a lethal inflammatory bowel disease (IBD) in the recipients. In contrast, IBD was not observed in SCID mice transplanted with unfractionated splenic cells. The earliest detectable pathological changes after CD4⁺ T cell transfer were proliferation and hypertrophy of the entire colonic epithelial layer, including increased mitotic activity, increased expression of epithelial nuclear proliferation antigen, and elongation of the crypts. Later on, massive mononuclear cell infiltration, hypertrophy of all layers of the colon and occasional epithelial ulcerations were observed. At this stage, accumulations of IgA, IgM and small numbers of IgG1-, IgG2-and IgG3-secreting plasma cells were present in the lamina propria of both the small and large intestine. We conclude that low numbers of intraveneously transferred CD4⁺ T cells induce IBD in SCID mice. In the late stages of CD4⁺ T cell-induced IBD, the colonic lamina propria becomes infiltrated with macrophages, neutrophils and plasma cells secreting IgA, IgM, and to a lesser degree IgG antibodies which might play an accessory role in the pathogenesis of IBD.     

The functional state of follicular dendritic cells in severe combined immunodeficient (SCID) mice: Role of the lymphocytes

In the present study, we have investigated the capacity of follicular dendritic cells (FDC) to trap immune complexes (IC) in the splenic white pulp of severe combined immunodeficient (SCID) mice and the influence of lymphocyte transfer on FDC function. FDC are absent in the splenic white pulp of naive SCID mice as revealed by in vitro IC trapping assay. One week after transfer of syngeneic lymphocytes, functional FDC with complement receptors appeared in the primary follicles coincident with B cell segregation, and IC were trapped on those FDC in a complement-dependent manner. Next, we immunized the reconstituted SCID mouse to see whether another type of FDC could be induced in the secondary follicle. Antigenic stimulation induced FDC with an additional capacity to capture IC via FcR γ II. As seen in immunocompetent mice, this type of FDC was located only in the light zone of the secondary follicle. The newly generated FDC did not carry H-2 antigen of transferred lymphocytes from F₁ mice. In SCID mice, in which normally no functional FDC are detectable, the microenvironments of the splenic white pulp have a capacity to develop and differentiate normally after transfer of lymphocytes. Apparently, the generation of functional IC-trapping FDC causes the induction of complement receptor(s) and Fc receptor on meshwork cells, which requires the presence of the lymphocytes.     

A Markov model to analyze cost-effectiveness of screening for severe combined immunodeficiency (SCID)

Objective

To evaluate the cost-effectiveness of universal neonatal screening for T cell lymphocytopenia in enhancing quality of life and life expectancy for children with severe combined immunodeficiency (SCID).

Methods

Decision trees were created and analyzed to estimate the cost, life years, and quality adjusted life years (QALYs) across a population when universal screening for lack of T cells is used to detect SCID, as implemented in five states, compared to detection based on recognizing symptoms and signs of disease. Terminal values of each tree limb were derived through Markov models simulating the natural history of three cohorts: unaffected subjects; those diagnosed with SCID as neonates (early diagnosis); and those diagnosed after becoming symptomatic and arousing clinical suspicion (late diagnosis). Models considered the costs of screening and of care including hematopoietic cell transplantation for affected individuals. Key decision variables were derived from the literature and from a survey of families with children affected by SCID, which was used to describe the clinical history and healthcare utilization for affected subjects. Sensitivity analyses were conducted to explore the influence of these decision variables.

Results

Over a 70-year time horizon, the average cost per infant was $8.89 without screening and $14.33 with universal screening. The model predicted that universal screening in the U.S. would cost approximately $22.4 million/year with a gain of 880 life years and 802 QALYs. Sensitivity analyses showed that screening test specificity and disease incidence were critical driving forces affecting the incremental cost-effectiveness ratio (ICER). Assuming a SCID incidence of 1/75,000 births and test specificity and sensitivity each at 0.99, screening remained cost-effective up to a maximum cost of $15 per infant screened.

Conclusion

At our current estimated screening cost of $4.22/infant, universal screening for SCID would be a cost effective means to improve quality and duration of life for children with SCID.     

Tetanus toxoid-specific T cell responses in severe combined immunodeficiency (SCID) mice reconstituted with human peripheral blood lymphocytes

SCID mice reconstituted with human peripheral blood lymphocytes (PBL) have repeatedly been shown 10 produce antigen-specific B ceil responses. We have derived tetanus toxoid (TT)-specific human T cell lines from cells of the peritoneal cavity, spleen and lymph nodes of SCID mice reconstituted with human PBL and boosted with TT. Establishment of these cell lines was dependent on the time interval between reconstitution of the mice with human PBL and initiation of lymphocyte cultures in vitro. When lymphocytes were collected from the mice 8 weeks after reconstitution, human lymphocytes with TT-specific proliferative activity in vitro were isolated from the peritoneal cavity and spleen, but long-term cell lines could not be established after repeated lymphocyte stimulation with TT. IL-2 and autologous Epstein Barr virus-transformed B cells. In contrast, three long-term (>10 months) TT-specific human T cell lines were established from lymphocytes collected from two of the eight mice in the group 4 weeks after reconstitution. The T cell lines were either CD4⁺ (two lines derived from peritoneal cavity and lymph node, respectively) or CD8⁺ (one line derived from spleen) and all expressed CD3, T cell receptor α/β, and human histocompatibility leucocyte class I antigen. The T cell lines, however, lacked cytotoxic, helper and suppressor activities. Thus, SCID mice can support human T cells that actively migrate to various organs and respond to antigenic stimuli both in vivo and in vitro, but these T cells lack characteristic functions.     

Lupus manifestations in severe combined immunodeficient (SCID) mice and in human/mouse radiation chimeras

The objective of this study was to develop a human lupus model. To this end we have established and compared two models: (1) severe combined immunodeficient (SCID) mice reconstituted with peripheral blood lymphocytes (PBL) of either systemic lupus erythematosus (SLE) patients or healthy controls and (2) lethally irradiated BALB/c mice radioprotected with bone marrow of SCID mice, to which human PBL were transferred (human/mouse chimera). Engraftment was successful in most (78.4%) recipient mice as determined by the levels of human IgG measured. In about 50% of either SCID mice or human/mouse chimeras that were successfully engrafted with PBL of SLE patients, significant anti-dsDNA autoantibodies, mostly of the IgG1 and IgG2 isotypes, were determined. Interestingly, in a significant number (84.5%) of recipients of PBL of the healthy controls, anti-dsDNA antibodies were observed as well, suggesting that PBL of at least some of the healthy controls have the potential to develop SLE-associated autoantibodies under the appropriate stimulatory conditions. Glomerular immune deposits (human IgG, mouse C3) were detected in 70–80% of SCID mice with human DNA specific antibodies and in a third of the human/ mouse chimeras. Thus, SLE serology and glomerular pathology were reproducibly demonstrated in two models of human SLE. These models should allow the evaluation of potential therapies for the treatment of lupus patients.     

人M5型白血病-SCID小鼠模型的建立及白血病病理变化的分析

目的:建立人M5型白血病细胞系SHI-1/SCID(重症联合免疫缺陷)小鼠模型,探讨白血病细胞的接种密度与SCID小鼠成瘤率及病理变化的关系。方法:将不同密度的人白血病细胞SHI-1注射至SCID小鼠腹腔。定期尾静脉取血并以流式细胞术(FCM)监测肿瘤细胞表面标志CD14及CD137L的变化。通过病理组织学检查和FCM分析SCID小鼠的骨髓、肝脏、脾脏和肾脏中白血病细胞的浸润及病理变化。结果:将不同密度的SHI-1细胞移植至小鼠腹腔,均可发现瘤块生长。同时中、高剂量组小鼠的主要组织器官呈现不同程度的肿瘤细胞的浸润。最早在移植3周后即可在尾静脉检测到肿瘤细胞,并与注射细胞量相关。结论:建立的SHI-1/SCID小鼠模型为人M5型白血病的研究提供了有价值的动物模型。     

Long-term efficacy of enzyme replacement therapy for adenosine deaminase (ADA)-deficient severe combined immunodeficiency (SCID)

Adenosine deaminase (ADA)-deficient Severe Combined Immunodeficiency (ADA-deficient SCID) is characterized by impaired lymphocyte development and function resulting from the adenosine metabolism defect. Enzyme replacement therapy with polyethylene glycol-conjugated adenosine deaminase (PEG-ADA) minimizes infectious complications of ADA-deficient patients who have not received bone marrow transplantation. In PEG-ADA therapy, enzymatically active ADA continuously circulates to act as a metabolic sink, detoxifying the adenosine and deoxyadenosine metabolites that accumulate to high levels in the absence of ADA. Studies have shown that upon the initiation of PEG-ADA therapy, the absolute numbers of circulating T and B lymphocytes and NK cells increase and protective immune function develops. However, the long-term efficacy is unknown. This retrospective study was designed to assess the long-term effectiveness of PEG-ADA treatment, based on evaluation of the immune function of nine ADA-deficient SCID patients (age 5-15) treated over the past decade. The results showed that the lymphocyte counts of all of the PEG-ADA treated patients were below the normal range at all times, despite initial improvements. A gradual decline of mitogenic proliferative responses occurred after a few years of treatment and normal antigenic response occurred less than expected. To this date, these low numbers and functions of lymphocytes had been adequate to provide protective immunity. These patients should be followed closely to detect a premature decline in immune function with aging in future decades of PEG-ADA therapy.     

Tumour necrosis factor-alpha (TNF-alpha) enhances lymphocyte migration into rheumatoid synovial tissue transplanted into severe combined immunodeficient (SCID) mice

Adhesion mechanisms play a major role in the recruitment of peripheral blood lymphocytes (PBL) which characteristically infiltrate rheumatoid arthritis (RA) synovium and other chronically inflamed tissues. Through a sequential series of complex integrated adhesion and signalling events, 'multistep model of migration', specific subsets of PBL are recruited into inflamed tissues. In this process both leucocyte receptors and microvascular endothelial (MVE) counter-receptors play a critical role. The MVE in particular, during an inflammatory state, is the target of various inflammatory mediators that cause the up-regulation of several cell adhesion molecules (CAM). One of the most important factors known to be a powerful inducer of MVE CAM is TNF-alpha. Conversely, blocking TNF-alpha causes a down-modulation of CAM expression. To test directly the capacity of TNF-alpha to induce cell migration into RA synovium we adapted a model in which synovial grafts were implanted into SCID mice subcutaneously. Using this model we demonstrate that: (i) transplants remain viable and become vascularized and fed by mouse subdermal vessels; (ii) the mouse vasculature connects to the transplant vasculature which maintains the ability to express human CAM; (iii) intragraft injections of TNF-alpha up-regulate the expression of human CAM, following the down-regulation which occurred 4 weeks post-transplantation; and (iv) the up-regulation of graft CAM is associated with increased human PBL migration into the transplants. This study provides direct evidence in vivo of the capacity of TNF-alpha to induce cell migration. In addition, it provides the experimental background for the optimal use of this model.     

Mature helper T cell requirement for immunoglobulin production by neonatal naive B cells injected intraperitoneally into severe combined immunodeficient (SCID) mice

It is accepted that human neonatal naive B cells produce mainly IgM in vivo as well as in vitro. Our previous work has demonstrated that i.p. injection of neonatal B cells together with adult mature T cells induces substantial levels of human IgG in the serum of SCID recipient mice. The present study was further attempted to determine the cellular components required for immunoglobulin production by neonatal B cells in SCID mice. When neonatal B and adult T cells were transferred into the SCID mice, human immunoglobulins, largely of IgG, were maximally detected in the serum around 6 weeks after a cell transfer. Depletion of CD4⁺ T cells from adult T cells resulted in undetectable levels of human immunoglobulin in the serum. By contrast, CD4⁺ T cell-enriched populations exhibited an enhancing effect on immunoglobulin production by neonatal B cells. Higher levels of immunoglobulin, including IgA and IgM, were detected in the peritoneal fluid than in the serum as early as 2 weeks after the cell transfer. Human T cells expressing activation antigens such as CD45RO and HLA-DR antigens were identified in the peritoneal lavages. These results suggest that neonatal naive B cells are able to differentiate into cells producing all classes of immunoglobulin in the presence of mature CD4⁺ T cells in a SCID mouse environment. The peritoneal cavity of SCID mice appears to provide a suitable place for immune responses by human cells, possibly in association with a certain xenogeneic reaction.     

Islet xenograft destruction in the hu-PBL-severe combined immunodeficient (SCID) mouse necessitates anti-CD3 preactivation of human immune cells

Introduction of the hu-PBL-SCID mouse model has yielded a potentially useful tool for research in transplantation. The aim of this study was to define the conditions necessary for a reconstituted human immune system to destroy in a consistent manner rat islet xenografts in the alloxan-diabetic hu-PBL-SCID mouse. We examined different time points of hu-PBL reconstitution, different transplantation sites of the islets and several hu-PBL reconstitution protocols. Major differences in graft destruction were observed between the different hu-PBL reconstitution protocols, irrespective of timing of hu-PBL reconstitution or site of transplantation. Although preactivation of hu-PBL did not improve the level of hu-PBL chimerism, histological and immunohistochemical analysis of the grafts revealed a severe human lymphocytic infiltration and beta cell destruction only in the grafts of mice receiving preactivated hu-PBL. This beta cell injury resulted in impaired glucose tolerance, with in some animals recurrence of hyperglycaemia, and decreased insulin and C-peptide levels after glucose stimulation. Therefore, we conclude that activation of hu-PBL prior to transfer is essential in achieving xenograft infiltration and destruction in hu-PBL-SCID mice. The need for immune manipulation suggests that interactions between hu-PBL and xenografts in this model may be hampered by incompatibilities in cross-species adhesion and/or activation signals.     

Modulation of hu/mu severe combined immunodeficient (SCID) mouse arthritis by local application of human recombinant IL-1β, IL-2 and IL-6

The contribution of interleukins produced by most inflammatory cells to chronic arthritis is not well understood. Therefore, we investigated the influence of several human recombinant interleukins (IL-1β, IL-2 and IL-6) on joint swelling, on the inflammatory process, and on serological parameters in a novel animal model of arthritis, the human/murine SCID arthritis. In this model an arthritis is induced by implanting human synovial tissue from patients with rheumatoid arthritis (RA) into the knee joint of mice with SCID. These mice tolerate the xenogeneic implant and develop a mixed human/murine pannus tissue. The interleukins were injected daily for 7 or 14 days after implantation. IL-1β led to a significant increase in joint swelling. It intensified the inflammatory process accompanied by enhanced migration of murine inflammatory cells into the knee joint. The production of human IL-6 in the transplanted tissue was stimulated through the application of IL-1β, and the serum level of human IL-6 was thus significantly higher than in controls. We could not observe a significant influence of IL-1β on the production of human IgG or IgM by the implant. The application of human IL-2 had a weak effect similar to that of IL-1β, but without statistical significance. Although IL-6 is a good marker for inflammation in RA, the application of recombined human IL-6 had no influence on the inflammatory process in this model.     

Increased expression of soluble form of vascular cell adhesion molecule-1 aggravates autoimmune arthritis in MRL-Fas(lpr) mice

Vascular cell adhesion molecule-1 (VCAM-1, CD106) is important in leukocyte trafficking and its increased expression is associated with a number of chronic inflammatory diseases, including rheumatoid arthritis (RA). A soluble form of VCAM-1 (sVCAM-1) is generated by shedding of the membrane-bound molecule. The concentration of sVCAM-1 is increased in the sera of RA patients, but its pathological role has not been elucidated. The effect of sVCAM-1 relative to protection or aggravation of disease on the development of spontaneous arthritis was examined in an animal model of RA, namely MRL-Fas(lpr) mice (which display a disease resembling human RA), by generation of sVCAM-1 transgenic MRL-Fas(lpr) mice. Transgenic MRL-Fas(lpr) mice that expressed sVCAM-1 had higher incidence and increased severity of arthritis associated with higher levels of serum IgG rheumatoid factor compared with non-transgenic MRL-Fas(lpr) mice. These results suggest that sVCAM-1 plays an arthritogenic role in the development of inflammatory arthritis in MRL-Fas(lpr) mice and may present an important target for therapeutic strategy of RA.     

Efficacy of (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine and 9-(1,3-dihydroxy-2-propoxymethyl)guanine for the treatment of murine cytomegalovirus infection in severe combined immunodeficiency mice.

Mice with severe combined immunodeficiency (SCID) inoculated intraperitoneally with murine cytomegalovirus (MCMV) develop a wasting syndrome at 3-4 days and die at 6-9 days after the infection. 9-(1,3-Dihydroxy-2-propoxymethyl)guanine (DHPG, ganciclovir) and (S)-1-(3-hydroxy-2-phosphonylmethoxypropyl)cytosine (HPMPC) were compared for their efficacy against MCMV-induced disease and mortality in SCID mice. Under all treatment conditions, i.e., administration of the test compounds for 5 consecutive days starting on the day of infection (day 0), for 5 consecutive days starting on day 4 after the infection, 2 periods of 3 consecutive days starting on day 0 and day 9 after infection, or as a single dose on day 3 before infection, HPMPC proved far superior to ganciclovir in delaying the onset of the disease and increasing the lifespan of the MCMV-infected mice.     

Complete arrest from pro- to pre-B cells in a case of B cell-negative severe combined immunodeficiency (SCID) without recombinase activating gene (RAG) mutations

The B-cell lineage in a patient with B-cell-negative severe combined immunodeficiency (SCID) was analysed by using antisurrogate light chain (SL) MoAbs. Peripheral CD3(+) T cells and CD19(+) B cells were absent in the patient. The common gamma (gamma c) chain was expressed normally on the patient's peripheral NK cells and his peripheral mononuclear cells did not possess any mutations in recombinase activating gene (RAG)-1, 2. Normal levels of expression of Ku70 and Ku80 protein were found by Western blot analysis. The patient did, however, display an increase in fibroblast sensitivity to irradiation. Furthermore, flow cytometric analyses of bone marrow cells showed that surface IgM and cytoplasmic mu positive cells were absent and that CD19(+) B cells were composed of only CD34(+) terminal deoxynucleotidyl transferase (TdT)(+) SL(+) pro-B cells. The complete arrest of pro- to pre-B cell development in the SCID patient's bone marrow suggests that some genes involved in V(D)J recombination, excepting the RAG gene, may play a causative role in the immunodeficiency.