Liselotte Jansson

A humanized model for multiple sclerosis using HLA-DR2 and a human T-cell receptor

Multiple sclerosis (MS) is a complex chronic neurologic disease with a suspected autoimmune pathogenesis. Although there is evidence that the development of MS is determined by both environmental influences and genes, these factors are largely undefined, except for major histocompatibility (MHC) genes. Linkage analyses and association studies have shown that susceptibility to MS is associated with genes in the human histocompatibility leukocyte antigens (HLA) class II region, but the contribution of these genes to MS disease development is less compared with their contribution to disorders such as insulin-dependent diabetes mellitus. Due to the strong linkage disequilibrium in the MHC class II region, it has not been possible to determine which gene(s) is responsible for the genetic predisposition. In transgenic mice, we have expressed three human components involved in T-cell recognition of an MS-relevant autoantigen presented by the HLA-DR2 molecule: DRA*0101/DRB1*1501 (HLA-DR2), an MHC class II candidate MS susceptibility genes found in individuals of European descent; a T-cell receptor (TCR) from an MS-patient-derived T-cell clone specific for the HLA-DR2 bound immunodominant myelin basic protein (MBP) 84–102 peptide; and the human CD4 coreceptor. The amino acid sequence of the MBP 84–102 peptide is the same in both human and mouse MBP. Following administration of the MBP peptide, together with adjuvant and pertussis toxin, transgenic mice developed focal CNS inflammation and demyelination that led to clinical manifestations and disease courses resembling those seen in MS. Spontaneous disease was observed in 4% of mice. When DR2 and TCR double-transgenic mice were backcrossed twice to Rag2 (for recombination-activating gene 2)-deficient mice, the incidence of spontaneous disease increased, demonstrating that T cells specific for the HLA-DR2 bound MBP peptide are sufficient and necessary for development of disease. Our study provides evidence that HLA-DR2 can mediate both induced and spontaneous disease resembling MS by presenting an MBP self-peptide to T cells.

B cell-deficient mice do not develop type II collagen-induced arthritis (CIA)

To investigate the role of B cells in the development of CIA, a model for rheumatoid arthritis, we investigated susceptibility to CIA in mice lacking B cells due to the deletion of the IgM heavy chain gene (μMT). The μMT deletion was backcrossed into two different CIA‐susceptible strains, B10.Q and B10.RIII. Two different variants of the CIA model are inducible in these strains: in B10.Q with rat type II collagen (CII) and in B10.RIII with bovine CII. Homozygous deletion of the IgM gene led to the absence of B cells and dramatically reduced immunoglobulin levels compared with wild‐type mice. The deletion of IgM totally abrogated development of CIA in both strains, although the anti‐CII T cell response did not differ between the μMT and wild‐type controls. We conclude that B cells play a crucial role in the development of CIA.

Estrogen induces a potent suppression of experimental autoimmune encephalomyelities and collagen-induced arthritis in mice

We have earlier described a chronic relapsing experimental autoimmune encephalomyelitis (EAE) in B10.RIII mice induced with a peptide of myelin basic protein (MBP), mimicking the course of multiple sclerosis in man. We now show that estrogens ameliorate chronic EAE. Castration of female mice led to an earlier disease onset (day 9 +/- 2 postimmunization (p.i.) in castrated mice vs. day 16 +/- 4 p.i. in normal mice). Long-term treatment with high levels of 17 beta-estradiol (E2) given as Silastic implants led to a dramatically delayed onset of disease in both castrated and normal female mice (mean onset day was day 39 +/- 14 and day 50 +/- 3, respectively). Treatment of castrated females by injections of E2, at a concentration which induces the serum levels seen at late stage pregnancy, delayed the onset approximately 1 week (mean onset 21 +/- 8). In contrast, treatment with estriol (E3), which was also given at doses corresponding to those levels seen during pregnancy, delayed the disease onset for a longer time (mean onset day 31 +/- 5). Five times higher doses of E2, compared with those seen during pregnancy, were required to obtain similar effects as the low E3 dose. The same mouse strain (B10.RIII) is also susceptible to induction of collagen-induced arthritis (CIA). We show here that also CIA is suppressed by the same treatments with E2 and E3, suggesting that similar estrogen-mediated mechanisms may operate to suppress these T-cell-dependent autoimmune disease models.

Estrogen-mediated immunosuppression in autoimmune diseases

Abstract. Gender affects the susceptibility to many autoimmune diseases. Women have an increased risk of developing diseases such as rheumatoid arthritis and multiple sclerosis compared with men. The female preponderance is believed to depend in part on the influence of sex hormones on the immune system. The mechanism of estrogen-induced immune suppression both in human autoimmune diseases and their experimental animal model counterparts is discussed. In addition, the mechanisms of estrogen and anti-estrogens are discussed in relation to their possible use as future therapeutic anti-inflammatory agents.

Collagen induced arthritis as an experimental model for rheumatoid arthritis

The type II collagen (CII) induced arthritis animal model (CIA) provides opportunities to study the nature of autoimmune reactions leading to arthritis and may be used as a model for rheumatoid arthritis (RA). Thus, in similarity with RA, the CIA model, when induced with autologous CII, shows a chronic and progressive disease course. The susceptibility to both RA and CIA are correlated to the expression of certain MHC class II allotype genes. In both diseases are autoantibodies to CII and rheumatoid factors produced. Immunohistopathology of affected joints show in both diseases a dominance of activated macrophages/fibroblasts with a significant infiltration of activated T cells and an infiltration of granulocytes. We do here suggest that both RA and CIA are dependent on a synergy between delayed type hypersensitivity and immune complex mediated inflammarory mechanisems and that CIA provides opportunities for studies of immunspecific reactions leading to arthritis.

Genetic linkage analysis of collagen-induced arthritis in the mouse.

The genetic susceptibility to collagen‐induced arthritis (CIA) in mice, the most commonly used model for rheumatoid arthritis, has been analyzed. The highly susceptible B10.RIII strain was crossed with the resistant RIIIS/J strain and the F2 intercross mice were subjected to genomic screening using microsatellite markers. These strains share the MHC region on chromosome 17, known to be of importance in CIA (this locus is named Mcia1). The same cross has earlier been used to map the major genes outside the MHC controlling chronic relapsing experimental allergic encephalomyelitis (EAE). It was found that the major locus controlling CIA (Mcia2; lod 4.12) was located on chromosome 3 in the same region as one of the major loci controlling EAE (Eae3). The linkage was reproduced in a mouse strain in which the locus was isolated on the B10.RIII background at the N4I2 generation. A second putative locus was identified on chromosome 13 (lod 3.13). The present finding identifies new loci outside the MHC controlling CIA and provides evidence that mouse CIA is controlled by polymorphic genes.

Genes on the X chromosome affect development of collagen-induced arthritis in mice

Susceptibility to collagen‐induced arthritis (CIA) in mice is associated with a class II gene in MHC (Aq) but also with unknown genes outside MHC. Investigated here is the influence of genes on the X chromosome as well as the role of the X‐linked immunodeficiency (xid) mutation. Reciprocal male F1 hybrids, bred to be heterozygous or homozygous for Aq, showed a genetic influence in their susceptibility to develop CIA. Crosses were made between B10.G, B10Q, DBA/I, SWR/J, C3H.Q and CBA/Ca, and all Fi mice were castrated to avoid sex hormone modulation of the susceptibility. A differential timing of arthritis onset and severity were seen in the reciprocal F1 males. An exception was the reciprocal F1 male offspring from SWR/J and DBA/1 crosses which differed only in disease severity late in the course of the disease. The female F1 crosses did not show the same pattern of differential susceptibility to CIA as the F1 males. To exclude the possible influence the Y chromosome, F1 males of reciprocal crosses were back‐crossed to the parental strains creating offspring with equal X chromosomes but divergent Y chromosomes. No difference in development of arthritis was observed in these. The influence of the xid mutation was investigated next. The xid loci from the CBA/N mouse was bred into DBA/1 strain which is highly susceptible to CIA. The resulting congenic DBA/l‐xid strain was resistant to induction of CIA and did not develop an antibody response to type II collagen. We conclude that polymorphic genes on the X chromosome modulate susceptibility to CIA. The results from the experiments with mice carrying xid mutations confirm that such immune modulating genes exist on the sex chromosomes.

Oestrogen induced suppression of collagen arthritis. IV: Progesterone alone does not affect the course of arthritis but enhances the oestrogen-mediated therapeutic effect

The effects of 17 beta-oestradiol and progesterone on the development of type II collagen-induced arthritis (CIA) and the anti-type II collagen (CII) autoantibody response were investigated. Treatment with physiological doses of 17 beta-oestradiol, inducing serum levels below the estradiol peak at the end of pregnancy, abrogated the development of arthritis and suppressed the anti-CII autoantibody response. Treatment with progesterone alone did not have significant effects on the development of arthritis or on the anti-CII autoantibody response. However, a combined treatment with both progesterone and oestrogen in physiological doses induced a more pronounced suppression of CIA than the suppression induced with oestrogen treatment alone. These findings suggest that oestrogen, but not progesterone, may be the critical factor to explain the pregnancy-related down-regulation of CIA.

Genetic, hormonal and behavioural influence on spontaneously developing arthritis in normal mice

DBA/1 male mice develop arthritis spontaneously at the age of 4 months. The affected joints show cell‐rich pannus formation without T cell infiltration and only limited MHC class II expression. Specific pathogen‐free DBA 1 mice from different sources developed the same disease. Analyses of inbred mouse strains with various genetic backgrounds and F1 hybrids revealed that the disease is genetically dependent of DBA/1 recessive genes. However, F1 hybrids between DBA/1 and BXSB spontaneously developed arthritis with earlier onset than DBA/1 mice, suggesting that the BXSB autoimmune gene background had both permissive and contributing effects on the development of arthritis. The complete male preponderance for disease susceptibility was investigated by castration and testosterone treatment of DBA/1 males. No arthritis developed after castration and disease susceptibility was restored by testosterone treatment. Arthritis developed only where more than two males were kept in cages, suggesting an influence by aggressive behaviour. Thus, the spontaneous development of arthritis is dependent on hormonal and behavioural mediated effects and differs from experimental models for rheumatoid arthritis such as type II collagen‐induced arthritis and pristane‐induced arthritis. We conclude that the spontaneously developing arthritis in the normal DBA/1 strain may be more useful as a disease model for osteoarthritis than for rheumatoid arthritis.

Enhancement of collagen-induced arthritis in female mice by estrogen receptor blockage

OBJECTIVE To determine whether estrogen-mediated suppression of collagen-induced arthritis (CIA) in mice acts via the nuclear estrogen receptors (ERs). METHODS CIA was induced in noncastrated normal (B10.Q x DBA/1)F1 (QD) female mice. The mice were treated with the ER antagonist ICI 182,780, which binds to both ERalpha and ERbeta, either on days 2, 6, 10, and 14 or on days 14, 18, 22, and 26 after type II collagen (CII) immunization. The effects of treatment and development of arthritis were correlated with the estrus cycle by inspection of vaginal smears (VS). By a combination of treatments with both estriol (E3) and ICI 182,780 during the time of expected onset of CIA in castrated QD female mice, the protective effect of E3 in CIA was analyzed. RESULTS Treatment with ICI 182,780 of QD female mice immunized with CII triggered an earlier onset of arthritis during the period when the estrus cycle was blocked. The arthritis-modulating effect of ICI 182,780 was even obtained at doses that were insufficient to block estrus cycling, as observed in the VS response. E3 is an estrogen with low estrogenic potency but with a relatively potent antiarthritis effect. Doses of ICI 182,780 that were suboptimal for blocking estrus cycling blocked the E3-mediated suppression of CIA in castrated female mice. CONCLUSION These findings show that estrogen-induced suppression of CIA is mediated via the nuclear ERs and is operating at physiologic, possibly even subphysiologic, levels of estrogens.