Transition from interleukin 1 beta (IL-1 beta) to IL-1 alpha production during maturation of inflammatory macrophages in vivo.

In situ production of interleukin 1 alpha (IL-1 alpha) and IL-1 beta was investigated in Peyer's patches (PP) of mice undergoing an acute bacterial infection with Yersinia enterocolitica O8. Synthesis of IL-1 beta, as determined by immunohistochemistry, was found primarily in monocytes migrating into the inflamed PP. In comparison, synthesis of IL-1 alpha was temporarily delayed by at least 24 h and was only found in mature macrophages, which did not produce detectable levels of IL-1 beta. This indicates a transition from IL-1 beta to IL-1 alpha production during maturation of monocytes into inflammatory macrophages, and further emphasizes a dichotomy between IL-1 alpha and IL-1 beta.

Relation of regional articular cartilage morphometry and meniscal position by MRI to joint space width in knee radiographs.

OBJECTIVE: To ascertain the contribution of articular cartilage morphometry and meniscal position on MRI to joint space width (JSW) measured in the Lyon schuss radiograph of the knee. DESIGN: 62 obese women with knee OA and 99 non-obese female controls (mean age 56.6 years) were imaged using 3T MRI and coronal water excitation spoiled gradient echo sequences. Segmentation of femorotibial cartilage morphology and regional morphometric analysis was performed using custom software. Meniscal position was measured quantitatively in sagittal and coronal planes. Minimum space width (mJSW) was measured in the Lyon Schuss knee radiograph; Kellgren and Lawrence grades (KLG) were assigned on standing anteroposterior knee films. The relative contribution of regional cartilage thickness and meniscal position to mJSW was assessed initially in univariate models and subsequently with multivariable modelling. RESULTS: 65% of the variation in mJSW was explained by regional cartilage thickness measures, different KLG and meniscal coverage. Of these measures the medial tibia cartilage thickness measures and central region of the central medial femur (ccMF) play a consistent role in variations in mJSW observed across all KLG. Further ccMF and the addition of percent meniscal coverage to this model explains the remaining differences in mean mJSW found between those subjects with definite joint space narrowing (KLG3) and those without OA. CONCLUSION: The variation in radiographic mJSW is best described by five regional cartilage thickness measures and percent meniscal coverage. The magnitude of each measures contribution differs according to radiographic severity with more variability explained by cartilage thickness of ccMF cartilage thickness and percent meniscal coverage with more severe disease.

Isolation and characterization of biologically active murine interleukin-1 alpha derived from expression of a synthetic gene in Escherichia coli.

A murine interleukin-1 alpha (mIL-1 alpha) gene coding for amino acids 115 to 270 of the precursor protein (Lomedico, P.T., Gubler, U., Hellmann, C.P., Dukovich, M., Giri, J.G., Pan, Y.E., Collier, K., Semionow, R., Chua, A.O. and Mizel, S.B. (1984) Nature 312, 458-462) was chemically synthesized and expressed in Escherichia coli. mIL-1 alpha, in the form of insoluble inclusion bodies, accounted for approx. 30% of total cellular protein produced by the recombinant strain. A simple isolation protocol was developed in which inclusion body material was first solubilized in 3 M guanidine hydrochloride, and the mIL-1 alpha was then simultaneously purified and allowed to fold to its active conformation by dialysis against distilled water. This procedure yielded pure, biologically active mIL-1 alpha with 41% recovery of the mIL-1 alpha present in the guanidine hydrochloride extract. The purified preparation had the expected amino acid composition, a molar absorptivity of 28,200 M-1.cm-1 and a pI of 5.2. No methionyl-mIL-1 alpha was detected by N-terminal sequence analysis, and the endotoxin level was less than 10 pg per micrograms of mIL-1 alpha. The specific biological activity was 3.10(7) units/mg in a co-mitogenic thymocyte proliferation assay. In addition to full-length mIL-1 alpha, the preparation contained N-terminally truncated mIL-1 alpha species (mainly des-4 and des-6 amino acid forms). The truncated species were isolated and found to have the same biological activity as the complete polypeptide. Thus, the active fragment of mIL-1 alpha appears to consist of a proteinase-sensitive N-terminal region which is not essential for activity, and a proteinase-resistant core which harbors the essential determinants of its cytokine function.

Regulation of monokine gene expression: prostaglandin E2 suppresses tumor necrosis factor but not interleukin-1 alpha or beta-mRNA and cell-associated bioactivity.

Prostaglandin E2 (PGE2)-mediated suppression of macrophage interleukin-1 alpha,beta and tumor necrosis factor-alpha synthesis was examined at the cellular and molecular levels. Treatment of lipopolysaccharide (LPS)-stimulated adjuvant-elicited murine macrophages with 5 x 10(-7) M PGE2 caused a 70% reduction in cell-associated TNF but had no suppressive effect on cell-associated interleukin-1 (IL-1) activity. Consistent with this result, Northern blot and nuclear transcription analyses demonstrated suppression of TNF mRNA but PGE2 had no effect on IL-1 alpha and IL-1 beta mRNA accumulation, as compared to LPS controls. Immunoperoxidase staining for cell-associated TNF alpha, IL-1 alpha, and IL-1 beta demonstrated that PGE2 suppressed TNF, but not IL-1 alpha or -beta expression, supporting the bioassay data. These results imply that PGE2-mediated regulation of IL-1 alpha,beta and TNF alpha is quite distinct. Synthesis of TNF appears to be regulated at least at the level of transcription, whereas that for IL-1 alpha and -beta is regulated post-transcriptionally.

Biologic and immunohistochemical analysis of macrophage interleukin- 1 alpha, - 1 beta, and tumor necrosis factor production during the peritoneal exudative response.

The present study examined changes in lipopolysaccharide (LPS)-induced interleukin 1 (IL-1) and tumor necrosis factor (TNF) production by murine peritoneal macrophages during the chronic exudative response to Freund's complete adjuvant (CFA). Macrophages were isolated by peritoneal lavage and adherence at intervals over a 32 day period following i.p. injection of CFA. Optimal culture conditions for IL-1 and TNF production were predetermined, and it was found that IL-1 production was profoundly impaired at densities of above 150 cells/mm2, whereas TNF synthesis was more resistant to density effects. Using optimal conditions, we observed a sequential appearance of monokines. On day 0 there was minimal IL-1 production and no detectable TNF production. By days 4-7, IL-1 production reached maximum levels with a steady decline to baseline by day 32. TNF production steadily increased after day 2, reached maximal levels by days 16-20, and then partly declined by day 32. These findings were supported by kinetic analyses at specified days. When related to exudative events, it appeared that maximal IL-1 was associated with the recruitment stage of the reaction, whereas TNF production was associated with the established exudate. Immunohistochemical analysis revealed that TNF production could be related to the proportion of macrophages with cytoplasmic TNF expression. In contrast, IL-1 alpha and -1 beta expression was comparable among populations with 85-100% of cells showing cytoplasmic expression 6 hr after LPS stimulus. Whereas cytoplasmic IL-1 alpha persisted for the 18 hr study period, IL-1 beta disappeared from many adjuvant recruited cells. Our findings suggest that monokine production is orchestrated during macrophage recruitment and activation at sites of chronic inflammation.

Detection of collagenase-induced damage of collagen by 9A4, a monoclonal C-terminal neoepitope antibody.

To determine whether the collagen network is compromised by collagenase during acute inflammation, a monoclonal antibody (9A4) was developed with specificity for the C-terminal neoepitope sequence generated by collagenase-cleavage of type II collagen (Gly-Pro-Pro-Gly-Pro-Gln-Gly-COOH). 9A4 was shown to detect the collagen collagenase-cleavage neoepitope with a K = 1.7 x 10(-7) M (type II) and K = 2 x 10(-6) M (type I). It does not recognize uncleaved native or denatured collagen. Articular cartilage from control animals is unstained by 9A4. During acute inflammation elicited in hamsters by intra-articular LPS, positive staining for the 9A4 neoepitope indicated the collagen was damaged. Wheel running exercise was used to apply stress to control cartilage and cartilage from animals with damaged collagen. After 6 months of running, the cartilage from normal animals was unaffected. By contrast, in the group with damaged collagen, the cartilage was fibrillated in all animals and in half of those, the cartilage failed and bony eburnation resulted.

Matrix metalloproteinase-13 expression in rabbit knee joint connective tissues: influence of maturation and response to injury.

The hypothesis of the present work was that expression of matrix metalloproteinase-13 (MMP-13, collagenase-3) would be induced during conditions involving important matrix remodeling such as ligament maturation, scar healing and joint instability. Therefore, MMP-13 expression in the medial collateral ligament (MCL) during the variable situations of tissue maturation and healing was assessed. MMP-13 expression in three intra-articular connective tissues of the knee (i.e. articular cartilage, menisci and synovium) following the transection of the anterior cruciate ligament of the knee was evaluated at 3 and 8 weeks post-injury. MMP-13 mRNA (semi-quantitative RT-PCR) and protein (immunohistochemistry and Western blotting) were detected in all of the tissues studied. Significantly higher MCL mRNA levels for MMP-13 were detected during the early phases of tissue maturation (i.e. 29 days in utero and 2-month-old rabbits) compared to later phases (5- and 12-month-old rabbits). This pattern of expression was recapitulated following MCL injury, with very high levels of expression in scar tissue at 3 weeks post-injury and then a decline to levels not significantly different from control values by 14 weeks. Elevated mRNA levels correlated with increased protein levels for MMP-13 in both menisci and synovium following the transection of the anterior cruciate ligament and during medial collateral ligament healing. These results indicate that MMP-13 expression is regulated by a number of variables and that high levels of expression occur in situations when connective tissue remodeling is very active.

Isolation and characterization of biologically active murine interleukin-6 produced in Escherichia coli.

Interleukin-6 (IL-6) is a multi-functional cytokine produced and secreted by several different cell types, including those of the immune system. A cDNA coding for the mature murine IL-6 (mIL-6), which extends from amino acid (aa) 25 through 211, was cloned into a prokaryotic vector and then expressed in Escherichia coli. The recombinant mIL-6 (remIL-6) was isolated from bacterial inclusion bodies by solubilization in 4 M guanidine hydrochloride followed by gel-filtration chromatography. The protein was refolded to an active conformation by dialysis against 25 mM Na. acetate pH 5.5. A final step of purification and concentration on a cation exchange resin yielded pure and biologically active remIL-6. The purified preparation had the expected aa composition, as confirmed by aa analysis and pI of 7.0-7.1. The biological activity of the recombinant protein was measured in two systems; a proliferation assay employing 7TD1 cells, and a fibrinogen biosynthesis assay employing primary rat hepatocytes. Both assay systems demonstrated that the remIL-6 was active in the range of 10(8) units/mg, which is similar to that estimated for native cytokine. Antibodies raised in rabbits against remIL-6 neutralized the biological activity of both recombinant and native IL-6.

Identification and characterization of a C-terminally extended form of recombinant murine IL-6.

Murine interleukin-6 (mIL-6) was expressed in Escherichia coli in the insoluble fraction of cell lysates. Approximately equal amounts of two polypeptide species, reactive with anti-IL-6 antibodies, were produced. The two forms of mIL-6 were isolated and found to have identical N-terminal sequences initiated by Met-Phe-Pro-Thr-Ser-Gln-. Peptide mapping after endoproteinase glu-C digestion led to isolation and characterization of the C-terminal peptides from each of the two forms and allowed the source of the heterogeneity to be identified as a C-terminal addition of three amino acids, Gln-Lys-Leu, to authentic mIL-6. Inspection of the nucleotide sequence of the plasmid containing the mIL-6 gene and expression of the plasmid in other strains suggested that the addition of three amino acids was caused by a readthrough of the termination codon arising from an unexpected suppressor mutation in the original host strain. Although the C-terminus of IL-6 is critical for the activity of this cytokine, the IL-6 variant with extended C-terminus was fully active in two separate bioassays. This suggests that the additional amino acids do not disrupt the structure or function of this important region of the molecule.

Reduction of biological activity of murine recombinant interleukin-1 beta by selective deamidation at asparagine-149.

A biologically active preparation of murine recombinant interleukin-1 beta (mIL-1 beta) from Escherichia coli cell lysates contained tow forms of mIL-1 beta with pI 8.7 and pI 8.1, respectively. Treatment with 0.1 M Tris, pH 8.5, at 37 degrees C for 35 h converted the pI 8.7 form to the pI 8.1 form by the selective deamidation of an asparagine residue (Asn149) in the mIL-1 beta molecule. Deamidated mIL-1 beta had 3- to 5-fold lower co-mitogenic activity and receptor affinity than the unmodified form.

Cytokine vaccination: neutralising IL-1alpha autoantibodies induced by immunisation with homologous IL-1alpha.

High-affinity IgG autoantibodies (aAb) to IL-1alpha are among the most frequently found aAb to cytokines in humans. To establish an animal model with aAb to IL-1alpha, we immunised mice with recombinant murine IL-1alpha. Unprimed and Bacille Calmette-Guérin (BCG)-primed BALB/cA mice were vaccinated with IL-1alpha coupled to purified protein derivative of tuberculin (PPD). Both unprimed and primed animals developed IgG aAb to IL-1alpha. These aAb persisted at high levels more than 100 days after vaccination and did not cross-react with murine IL-1beta. The induced anti-IL-1alpha aAb inhibited binding of IL-1alpha to the murine T-cell line NOB-1 by simple competition and neutralised IL-1alpha, but not IL-1beta-induced IL-6 in vivo. The aAb did not induce visible discomfort in the animals. In conclusion, long-lasting and high levels of neutralising and specific IgG aAb to IL-1alpha can be induced in mice by vaccination with recombinant murine IL-1alpha conjugated to PPD. Studies of the effects of IL-1alpha aAb in such animals may help clarify the importance of naturally occurring IL-1alpha aAb in humans and permit the evaluation of future therapies with cytokine aAb in patients with immunoinflammatory diseases and cytokine-dependent tumours.

Analysis of collagenase-cleavage of type II collagen using a neoepitope ELISA.

We have developed monoclonal antibody 5109 against a unique highly acidic sequence in type II collagen. When paired with previously reported monoclonal antibody 9A4, 5109 can be used as the capture antibody in an ELISA assay for the neoepitope generated by collagenase-cleavage of type II collagen. The assay detects the sequence ZGlyGluX(759)GlyAspAspGlyProSerGlyAlaGluGlyProX(771)GlyProGlnGly(775) where Z is a variable length polypeptide, X is proline or hydroxyproline, and Gly(775) corresponds to C-terminal amino acid of the 3/4 piece after collagenase cleavage. Antibody 5109 detects the first and 9A4 the second underlined sequence. Antibody 5109 recognizes its epitope with a K=1.2x10(-8) M independently of hydroxylation of X(759). When X(771) is proline, the sequence is 90x more sensitively detected by this ELISA than when it is hydroxyproline. Type II collagen of human articular cartilage was fragmented by cyanogen bromide (CNBr) and trypsin. The immunoreactive fragment was captured with 5109 and sequenced. Proline(771) averaged 81% hydroxylated. Other 3rd position prolines were >97% hydroxylated. In urine of control individuals of 50-70 years of age, we failed to detect the presence of the collagen fragment in a majority (8/10) of specimens. The two controls with measurable levels averaged 123 pM. In a similar age cohort of osteoarthritic patients, the majority (9/10) showed measurable values of urinary collagen fragments averaging 312 pM. This assay can be used for monitoring type II collagen metabolism in patients with osteoarthritis.

Novel immunosuppressive agents. Potent immunological activity of some bensothiopyrano [4,3-c]pyrazol-3-ones.

A unique class of immunosuppressive agents has been found be the use of a mouse model of immunity. A number of bensothiopyrano[4,3-c]pyrazol-3-ones are potent inhibitors of both the humoral and cellular immune response developed in mice in response to El4 tumor cells. These compounds exhibit a selectivity for inhibiting the humoral response. Structure-activity relationships and Hansch analyses of data from the mouse model are discussed. One of the most potent compounds, 2-(4'-chlorophenyl)bensothiopyrano[4,3-c]pyrazol-3-one (1, CP-17 193), exhibits ED50 values for inhibiting the humoral and cellular responses in the range of 0.5-2 mg/kg, po, in the mouse model and also inhibits antibody production to several other antigens and prolongs skin graft survival in mice. These compounds are shown in several ways to be distinct from the lymphocytotoxic drugs cyclophosphamide and azathioprine.

Determining selectivity of drugs by quantitative two-dimensional gel analysis. A study of tenidap, piroxicam, and dexamethasone.

In vitro pharmacologic measures of drug specificity are well established, i.e. drug interaction with a specific target such as an enzyme, receptor, or ion channel. However, in vitro measures of drug selectivity, defined as effects on secondary targets, are lacking. Two-dimensional gel electrophoresis (2-D gel) was examined as a measure of drug selectivity by comparing the effects of three drugs, tenidap, piroxicam, and dexamethasone, on the synthesis of intracellular proteins in lipopolysaccharide (LPS)-stimulated murine macrophages. A set of 902 35S-methionine-labeled proteins were separated consistently, identified by their coordinates of apparent isoelectric point and molecular weight, and quantified. LPS altered the concentrations of 45 proteins. Tenidap, at 10 microM, affected a total of five proteins (suppressed three; stimulated two), whereas piroxicam, at 10 microM, suppressed two proteins. Dexamethasone at 0.01 microM suppressed eight proteins and stimulated one. Thus, none of the drugs reversed the LPS-induced changes. Two of the eight proteins suppressed by dexamethasone were also suppressed by tenidap and were identified as proIL-1 alpha and proIL-1 beta. Since the subset of affected proteins provided a unique protein "fingerprint" for each drug, the three drugs were mechanistically differentiated by 2-D gel analysis. Compared to LPS (5% affected proteins), all three drugs were selective (< or = 1% affected) with piroxicam > tenidap > dexamethasone. With identification of affected proteins, this technique can provide a useful in vitro assessment of drug selectivity.

The value of C-reactive protein measurement in rheumatoid arthritis.

Since 1973, assessment of serum concentrations of C-reactive protein (CRP) has been advocated as a objective measure of disease activity in rheumatoid arthritis (RA). Our review of clinical experience with CRP measurement suggests it has at least two important roles to play in the management of RA. First, persistently elevated CRP levels have prognostic value. In general, such elevated levels are found in those patients who are at greater risk for continuing joint deterioration and therefore may need more aggressive treatment and supportive care. Second, in general, improvement in CRP levels is an objective indication that a drug has produced a beneficial effect and thus may be useful to the physician for monitoring effects of therapy. Since CRP may be elevated in a number of conditions besides RA, a diagnosis of RA must be made before using CRP as a prognostic factor.

The effects of continuous administration of murine interleukin-1 alpha in the rat.

Recombinant murine IL-1 alpha was administered continuously to rats by means of osmotic pumps implanted intraperitoneally. Continuous infusion of rIL-1 alpha in a range between 0.12 and 12.0 micrograms/day for four days was found to produce concentration-dependent weight loss. Behavioral parameters were continuously monitored and recorded at the 3.0 micrograms/day concentration in electronically-monitored activity cages during Days 2 through 5 of rIL-1 alpha administration. Parameters were separated into those affected during the dark phase (active period) or the light phase (resting period). Eating activity was found to be significantly reduced during each dark period through day 5, when compared with either untreated or PBS vehicle-infused animals. During the fourth and fifth days of infusion, however, eating behavior in animals infused with rIL-1 alpha began to increase toward control level in the latter, but not the earlier, half of the dark period. In contrast, drinking behavior was found to be significantly elevated only during the light periods. Continuous infusion of rIL-1 alpha also produced significant reductions in both horizontal locomotor activity (crossovers) and vertical locomotor activity (rears). However, in contrast to the trend toward a return of normal eating behavior, locomotor activity remained decreased through the fifth day of rIL-1 alpha infusion. These results suggest changes that could be produced by IL-1 in chronic inflammatory disease and infection.

Nonsteroidal anti-inflammatory drugs: an analysis of the relationship between laboratory animal and clinical doses, including species scaling.

The pharmacologic activity of nonsteroidal anti-inflammatory drugs (NSAID) has generally been studied in multiple tests. We examined four commonly used tests [i.e., the carrageenan edema test (CARR), the ultraviolet light-induced erythema test (UVE), the phenyl benzoquinone stretching test (PBQ), and the acetic acid stretching test (RWTH)] to determine by statistical criteria which was the best predictor of human clinical dose. We found that CARR greater than UVE greater than PBQ greater than RWTH. The CARR test, but not UVE or PBQ, showed dose proportionality between laboratory test dose and clinical dose. The RWTH test appeared to show proportionality, but the sample size was quite small. With proportionality, the scaling factor between test dose and human dose could be examined. Dose was found to scale as surface area for CARR. This relationship could not be generalized and thus each pharmacologic test must be examined individually for scaling behavior between the test and human doses.

Specific, high affinity colchicine binding monoclonal antibodies: development and characterization of the antibodies.

Nine colchicine specific monoclonal antibodies have been developed by immunizing BALB/c mice with a colchicine-keyhole limpet hemocyanin (Col-KLH) conjugate prepared using a bishydroxysuccinimide coupling reagent. Of four immunization procedures examined, intraperitoneal injection of the antigen attached to acid treated E. coli resulted in the maximum antigen specific antibody titers. A colchicine bovine serum albumin (Col-BSA) conjugate, prepared using a water soluble carbodiimide coupling technique, formed the basis of an enzyme linked immunosorbent assay used for screening hybridomas for colchicine specific antibody secretion and for determining the relative affinity and specificity profile of the monoclonal antibodies. All antibodies demonstrated high affinity, saturable binding to colchicine and low cross-reactivity with a panel of compounds structurally related to colchicine. The IC50 for the highest affinity antibody, C44, was 3.6 +/- 0.84 nM colchicine in the competitive enzyme immunoassay. The affinity of this antibody determined from Scatchard analysis of antibody binding to tritiated colchicine was 0.66 +/- 0.11 nM. Antibody C44 has the level of specificity and affinity suitable for a sensitive and selective immunoassay of colchicine for monitoring therapeutic drug levels. In addition, this antibody provides a specific pharmacologic antagonist for studies of colchicine's therapeutic mechanism and has the potential to reverse colchicine toxicity.