Mycoplasma arthritidis, an agent of rodent arthritis, produces a potent superantigen (SAg), MAM. Previous work established that MAM is presented to T cells by murine H-2E or the homologous human HLA-DR molecules and that lymphocytes lacking a functional H-2E molecule fail to respond to MAM. Recently, more potent and purified preparations of MAM of known protein content have become available. This enabled us to more effectively compare the response of MAM with that of other SAgs by using lymphocytes from mice whose cells express different H-2A and HLA-DQ molecules. Here we demonstrate that cells from some H-2E-negative mouse strains respond to higher concentrations of MAM. By use of inbred, congenic, and recombinant mice, we show that these differences are, in fact, exercised at the level of the major histocompatibility complex (MHC) and that allelic polymorphisms at H-2A influence reactivity to MAM. In addition, polymorphisms at HLA-DQ, the human homolog of H-2A, also influence responsiveness to MAM. Cells expressing DQw6 (HLA-DQA1*0103 and DQBI*0601 chains) gave much higher responses to MAM than did cells expressing DQw8 (DQA1*0301 and DQB1*0302 chains). In fact, responses of lymphocytes expressing DQB1*0601 chains homozygously were as high as those observed for cells expressing a functional H-2E molecule. Murine lymphocytes responded less well to staphylococcal enterotoxin B (SEB) and SEA, but mouse cells expressing human MHC molecules gave much higher responses. The patterns of reactivity observed with cells expressing the various murine and human alleles differed for MAM, SEB, and SEA, suggesting that each of these SAgs interacts with different regions or residues on MHC molecules. It has been hypothesized that SAgs might play a role in susceptibility to autoimmune disease. Allelic polymorphisms at MHC loci might therefore influence susceptibility to autoimmune disease by affecting immunoreactivity to specific superantigens.
ABSTRACT Mycoplasma arthritidis mitogen (MAM) is a potent superantigen secreted by M. arthritidis , an agent of murine arthritis. Here we compare the abilities of MAM to induce a panel of cytokines in vitro and in vivo in BALB/c and C3H/HeJ mouse strains that differ in susceptibility to mycoplasmal arthritis. Splenocytes from both mouse strains produced high levels of all cytokines by 24 h following in vitro exposure to MAM. No differences in cytokine profiles were seen irrespective of the MAM dose. However, there were striking differences in cytokine profiles present in supernatants of splenocytes that had been collected from mice after intravenous (i.v.) injection of MAM and subsequently rechallenged with MAM in vitro. Splenocytes collected 24 and 72 h after i.v. injection of MAM and challenged in vitro with MAM showed the most marked divergence in the secreted cytokines. Type 1 cytokines were markedly elevated in C3H/HeJ cell supernatants, whereas they were depressed or remained low in BALB/c cell supernatants. In contrast, the levels of type 2 cytokines were all greatly increased in BALB/c cell cultures but were decreased or remained low in C3H/HeJ supernatants. Interleukin-12 mRNA and protein was also markedly elevated in C3H/HeJ mice, as were the levels of immunoglobulin G2a. The data indicate a major skewing in cytokine profiles to a type 1 inflammatory response in C3H/HeJ mice but to a protective type 2 response in BALB/c mice. These cytokine changes appear to be associated with the severe arthritis in C3H/HeJ mice following injection of M. arthritidis in comparison to the mild disease seen in injected BALB/c mice.
Mycoplasma arthritidis, an agent of chronic proliferative arthritis of rodents, secretes a potent soluble superantigen, MAM, that is active for both murine and human T and B lymphocytes. We now report the complete nucleotide and amino acid sequence of MAM and show it to be distinct from other proteins and not closely related phylogenetically to other superantigens. Two functional domains on MAM are identified based on the ability of peptides encompassing these regions to inhibit lymphocyte proliferation by the intact MAM molecule. One of these domains shares short sequences or epitopes with other microbial superantigens. The second domain contains the consensus legume lectin motif-beta, which is important for T cell activation by concanavalin (Con) A. MAM and Con A peptides containing this motif are functionally cross reactive, suggesting a novel secondary pathway for T cell activation by MAM.
To compare the efficacy and safety of chondroitin sulfate plus glucosamine hydrochloride (CS+GH) versus celecoxib in patients with knee osteoarthritis and severe pain.
Methods
Double-blind Multicentre Osteoarthritis interVEntion trial with SYSADOA (MOVES) conducted in France, Germany, Poland and Spain evaluating treatment with CS+GH versus celecoxib in 606 patients with Kellgren and Lawrence grades 2–3 knee osteoarthritis and moderate-to-severe pain (Western Ontario and McMaster osteoarthritis index (WOMAC) score ≥301; 0–500 scale). Patients were randomised to receive 400 mg CS plus 500 mg GH three times a day or 200 mg celecoxib every day for 6 months. The primary outcome was the mean decrease in WOMAC pain from baseline to 6 months. Secondary outcomes included WOMAC function and stiffness, visual analogue scale for pain, presence of joint swelling/effusion, rescue medication consumption, Outcome Measures in Rheumatology Clinical Trials and Osteoarthritis Research Society International (OMERACT-OARSI) criteria and EuroQoL-5D.
Results
The adjusted mean change (95% CI) in WOMAC pain was −185.7 (−200.3 to −171.1) (50.1% decrease) with CS+GH and −186.8 (−201.7 to −171.9) (50.2% decrease) with celecoxib, meeting the non-inferiority margin of −40: −1.11 (−22.0 to 19.8; p=0.92). All sensitivity analyses were consistent with that result. At 6 months, 79.7% of patients in the combination group and 79.2% in the celecoxib group fulfilled OMERACT-OARSI criteria. Both groups elicited a reduction >50% in the presence of joint swelling; a similar reduction was seen for effusion. No differences were observed for the other secondary outcomes. Adverse events were low and similarly distributed between groups.
Conclusions
CS+GH has comparable efficacy to celecoxib in reducing pain, stiffness, functional limitation and joint swelling/effusion after 6 months in patients with painful knee osteoarthritis, with a good safety profile.
Twenty‐four alleles have been defined for HLA‐DPB based on their second exon sequences. This paper describes a novel method, co‐digested amplified fragment length polymorphisms (CAFLP), for assigning these alleles to heterozygous patients, as well as to homozygous cell lines. The method depends on co‐digestion of amplified DNA by restriction endonucleases and separation of the resultant fragments with polyacrylamide gel electrophoresis. Co‐digestion by selected restriction enzymes produces a set of readily discernible fragments that are unique for a given haplotype because the selected restriction sites occur in cis. Consequently, this method provides haplotype information not available from independent digests and allows all known heterozygous genotypes to be identified. Analysis of 103 trios of mother, father, and child, plus 120 normal caucasians, demonstrates the reliability and simplicity of this procedure. This simple typing method results in unambiguous assignment of all current HLA‐DPB genotypes in random samples with a high proportion of heterozygous individuals.
In systemic sclerosis (SSc) the most common gastrointestinal tract (GIT) complaint is gastroesophageal reflux disease (GERD), which may contribute to oesophagitis, stricture, Barrett's oesophagus, and oesophageal adenocarcinoma. We used a genealogical resource the Utah Population Database (UPDB) to analyse SSc pedigrees for hereditability of oesophageal disease.SSc, GERD, oesophagitis, stricture, Barrett's, and oesophageal adenocarcinoma were defined by ICD Ninth and Tenth Revision codes. Familial aggregation, relative risk (RR) of the GIT disease in SSc proband and their relatives was estimated by Cox regression model. The model (adjusted for sex and birth year) was used to evaluate the effects of having or being related to, a case or control for SSc, on GIT diseases.We identified 2,227 unique SSc patients and 11,136 randomly selected controls matched by birth year, gender, and whether born in Utah, in an approximately 1:5 ratio. A SSc proband had a significant high risk of GERD (RR: 3.28), dysphagia (RR 5.58), oesophageal stricture (RR: 5.16), oesophagitis (RR: 4.86), and Barrett's (RR: 4.52) all with significant p-values <2e-16. First-degree relatives of a SSc proband were at elevated risk of GERD (RR: 1.14, p=6.85e-05), dysphagia (RR: 1.22 p=0.002), and oesophagitis (RR: 1.37, p=2.10e-06). First cousins (RR: 1.09, p=0.03) and spouses (RR; 1.37, p=0.02) were at increased risk of esophagitis and dysphagia.These data suggest that independent of GERD, oesophagitis in SSc patients and their relatives may have both a hereditable and environmental etiology. There does not seem to be a heritable component to Barrett's oesophagus.
