Comparison of cytokine secretion profiles provoked in mice by glutaraldehyde and formaldehyde

BACKGROUND: Glutaraldehyde and formaldehyde are commonly used sterilizing agents that are known skin sensitizers. There is some controversy, however, regarding their capacity to cause respiratory allergy. The authors have demonstrated previously that topical exposure of mice to chemical contact allergens such as 2,4-dinitrochlorobenzene (DNCB) or respiratory allergens such as trimellitic anhydride (TMA) induces characteristic cytokine secretion profiles consistent with the selective activation of T helper1 (TH1)- and TH2-type cells, respectively. OBJECTIVE: To investigate the quality of immune response provoked following topical exposure of mice to these materials. METHODS: BALB/c strain mice were exposed topically to 50% formaldehyde or to various concentrations of glutaraldehyde in acetone. Control animals were treated concurrently with the reference contact allergen DNCB (1% in acetone:olive oil [AOO]) or with the reference respiratory sensitizer TMA (10% in AOO). Thirteen days after the initiation of exposure, draining lymph node cells (LNCs) were cultured for 12-120h and cytokine content of supernatants analysed by cytokine-specific enzyme-linked immunosorbent assay. RESULTS: DNCB-alpha and formaldehyde-activated LNCs produced high levels of the TH1-type cytokine interferon gamma, but little of the TH2-type products interleukins 4 and 10. TMA- and glutaraldehyde-stimulated LNCs displayed the converse TH2-type pattern of cytokine expression. CONCLUSIONS: These data are consistent with glutaraldehyde, but not formaldehyde, having significant potential to cause allergic sensitization of the respiratory tract.     

Pathology and cell proliferation induced by intra-nasal instillation of aldehydes in the rat: comparison of glutaraldehyde and formaldehyde

The relative toxicities of formaldehyde and glutaraldehyde to the rat nasal epithelium were determined following intra-nasal instillation of aqueous solutions of these compounds into one nostril of male Fischer 344 (F-344) rats. Lesions identical in appearance to those resulting from acute inhalation exposure to formaldehyde were induced by both compounds in a concentration-dependent manner. Treatments included India ink or 1 M methylene blue (for instillation deposition studies); sterile saline (vehicle control); 40, 200, 400, and 800 mM formaldehyde; and 10, 20, and 40 mM glutaraldehyde. Dye-treated rats were sacrificed immediately, and nasal passages were examined to determine the localization of instilled materials. Three days after treatment, all other animals received a single ip injection of 5-bromo-2'-deoxyuridine 2 hr prior to sacrifice, and the nasal passages were prepared for histopathology and cell proliferation studies. While sterile saline and 10 mM glutaraldehyde induced no significant epithelial changes, 20 and 40 mM glutaraldehyde induced extensive lesions in the treated side of the nose. Aldehyde-induced lesions included inflammation, epithelial degeneration, respiratory epithelial hypertrophy, and squamous metaplasia in association with marked increases (3-8-fold) in labeling index for both compounds. Formaldehyde induced similar lesions but required concentrations of 200 mM or more to elicit a toxic response. Thus, glutaraldehyde is approximately an order of magnitude more toxic to the nasal epithelium than formaldehyde. These studies also indicate that the nose is very resistant to the aldehydes studied, requiring instillation of millimolar concentrations before toxic responses occurred.     

A study of the effects of glutaraldehyde and formaldehyde on the mechanical behaviour of bovine pericardium

The inherent variability in the mechanical behavior of bovine pericardium causes difficulties in establishing the effects of treatment procedures used in the manufacture of bioprosthetic cardiac valves. A new experimental technique has been developed in which the specimen acts as its own control, obviating the need to perform large numbers of experiments to obtain statistically significant results. The procedure used is described in detail as is the equipment employed. The technique was used to assess the effect of glutaraldehyde and formaldehyde on the stress/strain response of bovine pericardium. The results show that the fixing process in glutaraldehyde is virtually complete within two hours and causes significant changes in the mechanical behaviour of the tissue. The tissue becomes progressively stiffer as the treatment period is extended, which is especially pronounced at low levels of stress. Formaldehyde storage subsequent to fixing in glutaraldehyde was found to have no effect on the stress/strain response of the bovine pericardium.     

Calcification of subcutaneously implanted type I collagen sponges. Effects of formaldehyde and glutaraldehyde pretreatments.

Although collagen-containing implants are widely used in various surgical applications, there has been relatively little attention paid to the possibility that this type of biomaterial may undergo pathologic calcification which could compromise its function. The present study reports for the first time the calcification of a series of implants of purified collagen sponges prepared with graded degrees of aldehyde-induced cross-linkages (assessed by shrinkage-temperature, wetting time, and collagenase digestibility). Type I collagen sponges were pretreated with either glutaraldehyde (0.1% to 2.0% aqueous solution, for 5-180 minutes) or formaldehyde (as vapors for 15 minutes to 15 hours), and implanted subcutaneously for 21 days in weanling rats. Although specimens not pretreated with either aldehyde reagent and the formaldehyde sponges pretreated for 15 minutes were resorbed without evidence of calcification, all other aldehyde-pretreated implants mineralized. The degree of calcification did not correlate with extent of cross-linking. Formaldehyde-pretreated implants calcified more extensively (Ca2+ = 87.8 +/- 2.8 micrograms/mg, mean +/- standard error of the mean; n = 58) than did glutaraldehyde-pretreated implants (Ca2+ = 40.9 +/- 1.4 micrograms/mg; n = 52). It is concluded that both glutaraldehyde- and formaldehyde-pretreated Type I collagen sponges calcify after subdermal implantation in young rats. Although aldehyde pretreatment of Type I collagen sponge implants is a prerequisite for their eventual mineralization, the threshold level of aldehyde-induced cross-linking required to potentiate their maximal pathologic calcification is low.     

Mechanism of crosslinking of proteins by glutaraldehyde I: reaction with model compounds

3H-Glycine and 6-aminohexanoic acid were used as model amine compounds and reacted with glutaraldehyde. Based on the spectral characteristics and the molecular weights obtained from the reaction products, it is concluded that glutaraldehyde can modify amines to form an intermediate which absorbs at 300 nm and has a molecular weight of about 200. In the presence of excess glutaraldehyde, this intermediate is quickly converted to a much larger intermediate which absorb strongly at 265 nm. The larger intermediates are finally altered to yield a strong absorption peak at 325 nm with no apparent change in the molecular weight. These results suggest that a process of polymerization is induced by the initial reaction of glutaraldehyde with amines. The glutaraldehyde-polymer amine complex is self-limiting in size and can undergo internal rearrangement to become chemically inert.     

Effect of alkaline glutaraldehyde on hepatitis B virus antigens

The potential of alkaline 2 % glutaraldehyde solutions, with and without surface active agents, to alter the antigenicity of hepatitis B virus (HBV) was analyzed and compared to the antigenic alternation capacities of 0.525 % sodium hypochlorite and 2.02 % formaldehyde solutions. After treatment of a hepatitis B surface antigen-positive plasma at room temperature for 10 min, there was a 51–67 % reduction in surface antigen level and a 90–94 % decrease in hepatitis B core antigenicity. Glutaraldehyde is proposed as an alternative to the more noxious hypochlorite and formaldehyde solutions for disinfection of HBV-contaminated articles.     

Lysine-enhanced glutaraldehyde crosslinking of collagenous biomaterials.

Crosslinking of collagenous biomaterials currently employs the use of glutaraldehyde. The putative enhancement of glutaraldehyde crosslinking by lysine was investigated in three model systems: bovine pericardium, collagen membranes, and bovine serum albumin. Repetitive sequential treatment of bovine pericardium with glutaraldehyde and lysine and finally with formaldehyde produced a matrix which, by the two criteria used (shrinkage temperature and urea/SDS soluble collagen), was shown to be more highly crosslinked than pericardium fixed in glutaraldehyde alone. Essentially the same results were obtained when membranes prepared from pepsin-soluble pericardial collagen were subjected to sequential glutaraldehyde and lysine treatments, reaching shrinkage temperatures of more than 90 degrees C. Heart valves prepared from lysine-enhanced glutaraldehyde crosslinked bovine pericardium were tested in vitro in an accelerated fatigue tester and have been shown to behave satisfactorily after 300 million cycles. These additional crosslinks proved to be stable in saline at 37 degrees C. Studies on bovine serum albumin attempted to get an insight into the mechanisms of lysine enhancement of glutaraldehyde crosslinking by treating sequentially albumin with glutaraldehyde and lysine and analysis of the products by gel filtration and SDS-PAGE. These studies suggest that free amino groups exposed by proteins are initially reacted with glutaraldehyde and then bridged by the diamino compound (lysine) producing more extensive intermolecular crosslinking than glutaraldehyde alone.     

Evaluation of the genotoxic potential of glutaraldehyde

The cytotoxic and genotoxic effects of glutaraldehyde were studied in vitro in the human TK6 lymphoblast cell line and in primary cultures of rat hepatocytes. TK6 lymphoblasts were exposed to glutaraldehyde for 2 hr in serum-free GSH-free media. Cytotoxic effects were observed at concentrations as low as 10 microM with only 10% cell survival at 20 microM. Alkaline elution studies indicated that glutaraldehyde-induced DNA-protein crosslinking increased linearly over the concentration range from 0 to 25 microM. Glutaraldehyde-induced mutations were assessed at the thymidine kinase locus over the same concentration range and reached a plateau at 10 microM of about six times the background mutant frequency. At equivalent levels of DNA-protein crosslinks and cytolethality, glutaraldehyde was mutagenic at approximately a one-seventh lower concentration than the rodent nasal carcinogen formaldehyde (Craft et al.; Mutation Research 176:147-155, 1987). Glutaraldehyde induced a marginal increase in unscheduled DNA synthesis in the in vitro hepatocyte DNA repair assay, but only at the two highest concentrations of 50 and 100 microM, indicating the induction of some DNA excision-repair activity. These data demonstrate that glutaraldehyde exhibits DNA-reactive genotoxic activity that may involve, at least in part, DNA-protein crosslinking in these cell culture models. These findings suggest the need to examine the potential carcinogenic activity of glutaraldehyde in appropriate inhalation studies.     

Ferritin labeling of concanavalin A by glutaraldehyde. Comparison of different molar con A/ferritin/ glutaraldehyde ratios and characterisation of the products

Optimal conditions were investigated for preparation and isolation of monomeric Con A ferritin, with one molecule ferritin bound to one tetravalent molecule of Con A. Con A and ferritin were covalently coupled with highly purified glutaraldehyde as a bifunctional reagent at different molar ratios. The effect of four different concentrations of glutaraldehyde and of two different ratios of ¹²⁵I-Con A to ferritin on the yield of Con A-ferritin monomers were tested in one-step reactions.The different products were subjected to linear sucrose density gradient centrifugation and the amount of ¹²⁵I-Con A or ferritin or conjugates in the fractions obtained were measured by optical density at 280 nm (protein) and 310 nm (ferritin), gamma-counting (¹²⁵I-Con A) by quantitative immunoelectrophoretic techniques (free, ferritin, ferritin bound to Con A), and by counting relative numbers of ferritin monomers, dimers, trimers and larger oligomers under the electron microscope.In the 30–56% w/w sucrose gradient unlabeled Con A was optimally separated from ferritin or ferritin-labeled Con A monomers. Ferritin monomers and Con A ferritin monomers could be recovered at a sucrose concentration of 42 to 49% w/w. A high molar ratio of Con A to ferritin during the coupling reaction caused formation of high molecular weight Con A-polymers. Optimal yield of Con A-ferritin monomers was obtained with an equimolar ratio of Con A to ferritin, a glutaraldehyde to ferritin ratio of 26 : 1 and a final ferritin concentration of 310 nmoles/ml.     

The effect of glutaraldehyde fixation on the immunogenicity of allogeneic lymphoid and tumour cells.

When CBA mice were injected with allogeneic (DBA/2) lymph node cells treated with glutaraldehyde at concentrations of 0.13% and 0.013% they failed to produce a primary cytotoxic antibody response; cells fixed with 0.0013% glutaraldehyde only provoked the slightest of antibody responses. No significant secondary response was provoked by cells fixed with 0.013% glutaraldehyde in mice primed 8 weeks earlier with normal lymphoid cells. As it is well established that such cells can stimulate a secondary mixed lymphocyte reaction and have ben reported to induce a secondary haemagglutinin response their assumed antigenicity in these experiments was checked. It was found that fixed cells did not have measurable antigenicity as assessed by ability to absorb anti-H2 antibody. The organ localization of chromium-labelled glutaraldehyde-fixed lymph node cells showed a lack of localization in lymph nodes at all levels of fixation, though localization in the spleen of cells fixed with 0.0013% glutaraldehyde was very variable, consistent with the borderline immunogenicity of such cells. Mitomycin treatment only modestly reduced the immunogenicity of lymph node cells and did not affect their organ localization. When CBA mice were injected with allogeneic (DBA/2) tumour cells, P 815, fixed with 0.13% or 0.013% glutaraldehyde, no cytotoxic antibody was produced and cells fixed with 0.0013% glutaraldehyde stimulated an erratic low response again suggesting a borderline level of activity. However P 815 cells fixed with 0.13% glutaraldehyde retained their antigenicity as assessed by absorption. Mitomycin treatment of P 815 cells had only a modest deleterious effect of their immunogenicity. These differences in immunogenicity are discussed in relation to the viability of cells required to stimulate an allo-cytotoxic antibody response.     

溴结构域蛋白4抑制剂JQ1在甲醛诱导小鼠炎性痛中的作用及机制

目的 探讨溴结构域蛋白4（BRD4）抑制剂JQ1在甲醛诱导炎性痛模型小鼠脊髓中的表达变化及作用。 方法 32只ICR小鼠随机分为生理盐水组、甲醛注射5 min、30 min和60 min组,每组8只,Western blotting（n=4/组）和Real-time PCR（n=4/组）检测各组小鼠脊髓BRD4的蛋白和mRNA的表达水平;66只小鼠随机分为甲醛注射组,溶媒（DMSO）加甲醛注射组,以及6.25、12.5、25 和50 mg/kg JQ1注射加甲醛溶液组,每组11只,观察BRD4抑制剂JQ1对每组小鼠自发性疼痛的影响（n=11/组）;免疫组织化学（n=3/组）、Real-time PCR（n=4/组）或Western blotting（n=4/组）的方法检测25 mg/kg JQ1对模型小鼠脊髓即早基因c-fos及谷氨酸受体2(GluR2)表达的影响。 结果 甲醛注射后30 min和60 min,小鼠脊髓BRD4的蛋白（P<0.01）和mRNA水平明显升高（P<0.05）;行为学结果显示,25 mg/kg和50 mg/kg JQ1处理组小鼠第Ⅱ相痛反应持续时间与溶媒（DMSO）组相比均明显缩短（P<0.05）; 免疫组织化学及Real-time PCR结果显示,25 mg/kg JQ1干预明显减少小鼠脊髓c-fos的阳性细胞数（P<0.05) 和mRNA水平（P<0.05）,Western blotting结果显示,25 mg/kg JQ1干预明显降低甲醛诱导的小鼠脊髓GluR2（P<0.001）的蛋白表达。 结论 BRD4在炎性痛中枢敏化中起重要作用,JQ1可能是通过抑制疼痛中枢敏化的形成从而缓解炎性疼痛。     

Prevention of calcification of glutaraldehyde pretreated bovine pericardium through controlled release polymeric implants: studies of Fe, Al, protamine sulphate and levamisole

Calcification is the principal cause of the clinical failure of bioprosthetic heart valves fabricated from glutaraldehyde pretreated porcine aortic valves or bovine pericardium. The present study investigated controlled-release implants for prevention of the calcification of glutaraldehyde pretreated bovine pericardium in a rat subdermal model. Either Al³⁺ and Fe³⁺ (inhibitors of the growth and dissolution rate of hydroxyapatite crystals), levamisole (alkaline phosphatase inhibitor) or protamine sulphate (charge modifier) were individually incorporated into various polymeric carriers (either silicone rubber. Polyurethane or silicone rubber-polyurethane copolymer). Polymeric implants were evaluated for in vitro release kinetics, which revealed that sustained drug release was obtained from 21 d to more than 90 d from various drug matrices. In vivo efficacy was studied by co-implanting the polymeric delivery systems with glutaraldehyde pretreated bovine pericardium for 21 d using a subdermal rat model; glutaraldehyde pretreated bovine pericardium calcium levels were quantitated by atomic absorption spectroscopy in the explanted tissues. Fe³⁺ and Al³⁺ polymeric implants were the most effective for inhibiting deposition of calcium mineral. Al³⁺ demonstrated 82% inhibition of calcification compared to controls and Fe³⁺ resulted in 80% inhibition of calcification. Specific histologie staining methods showed that Fe³⁺ and Al³⁺ were localized within the devitalized cells of the explanted glutaraldehyde pretreated bovine pericardium. No adverse effects on somatic growth or recipient bone morphology were noted following controlled-release drug administration. Controlled release of protamine sulphate or levamisole did not significantly inhibit glutaraldehyde pretreated bovine pericardium calcification. It is concluded that regional controlled release of Fe³⁺ or AI³⁺ inhibits glutaraldehyde pretreated bovine pericardium calcification in the rat subdermal model without adverse effects.     

Effect of glutaraldehyde on the antigenicity and infectivity of hepatitis A virus

The effect of glutaraldehyde on the antigenicity and infectivity of hepatitis A virus (HAV) was examined. The CF 53 strain, adapted to human hepatoma PLC/PRF/5 cells, was treated with glutaraldehyde using three different concentrations, 0.02, 0.10, and 0.50%, for various periods of time, 3, 10, and 30 min, respectively. After the virucidal assays, glutaraldehyde and HAV were separated by gel filtration, then the antigen (radioimmunoassay) titer and the infectivity titer were determined. The greatest antigen titer reduction was about 80% after 30 min using 0.10% glutaraldehyde and within only 3 min using 0.50% glutaraldehyde. Glutaraldehyde is an effective disinfectant against HAV: the infectious virus titer decreased by more than 3 log10 after 30 min using 0.10% glutaraldehyde and within only 3 min using 0.50% glutaraldehyde. Statistical studies showed that the decrease of antigen or infectious virus titer was affected by both glutaraldehyde concentration and exposure time.     

An improved conjugation method for controlled covalent coupling of synthetic peptides to proteins using glutaraldehyde in a dialysis method

Controlled and efficient conjugation of synthetic peptides to proteins, for use in immunization or in assay procedures, is a prerequisite for the immunological applications of synthetic peptides. This study describes a new method of conjugating synthetic peptides to proteins in such a way that no homopolymers of synthetic peptides or proteins occur. To achieve this, the protein is first activated with glutaraldehyde and subsequently excess glutaraldehyde is removed. Then coupling of the synthetic peptide to the activated protein occurs while subsequetly the surplus reactive glutaraldehyde groups on the protein are blocked with lysine. Excess free peptide and lysine is then removed by dialysis. This improvement not only results in better defined conjugates when compared to classical glutaraldehyde coupling, but also in the consumption of smaller amounts of synthetic peptide during conjugate formation. When used for immunization we obtained similar and sometimes even better responses with the glutaraldehyde based conjugates than with succinimidyl (MBS) conjugates of the same peptides. The performance of the modified conjugates in ELISA procedures, immunization and immunocytochemistry suggests that they are superior to conjugates formed by classical glutaraldehyde coupling.     

The preparation and physicochemical characterization of an injectable form of reconstituted, glutaraldehyde cross-linked, bovine corium collagen

Pepsin-solubilized bovine corium collagen was purified, reconstituted, and treated with various levels of glutaraldehyde. Treatment of suspensions of fibrillar collagen with low concentrations of glutaraldehyde appeared to have little effect on the gross morphology of fibrils, as judged by electron microscopy, but did have a significant impact on their physicochemical stability. Fibrillar collagen treated with glutaraldehyde at a concentration equal to or greater than 0.0075% demonstrated significant decreases in neutral solubility at elevated temperatures as compared to noncross-linked controls. Differential scanning calorimetry provided a convenient and quantitative means to correlate increases in melting temperature with increases in glutaraldehyde treatment concentration. Fibrillar collagen cross-linked with glutaraldehyde concentrations as low as 0.0075% demonstrated a significantly greater resistance to proteolytic degradation than did noncross-linked fibrillar collagen samples. The residual, extractable aldehyde content of such preparations was between 1 and 3 ppm. Rheological measurements on such cross-linked suspensions demonstrated that they were non-Newtonian, shear-thinning fluids, and that they were two- to threefold more viscous than corresponding preparations of noncross-linked collagen.     

Mycobactericidal activity of glutaraldehyde solutions.

Aqueous solutions of alkaline glutaraldehyde (buffered at pH 8.5) inactivated a standard suspension of Mycobacterium tuberculosis H37Rv faster than the corresponding acid (pH 3.7 preparation. Quantitative differences in the rate of inactivation of eight other species of Mycobacterium were determined using a 1% solution of alkaline glutaraldehyde and inactivation of residual glutaraldehyde with 1% sodium bisulfite solution. Variations in the rate of kill were observed between the various mycobacterial species tested, but such differences were probably not sufficiently large to be of practical importance. A 2% alkaline glutaraldehyde solution inactivated 10(5) viable M. tuberculosis cells present on the surface of porcelain penicylinders within 5 min at 18 degrees C. This rate of inactivation was faster than in the acidic solution.     

Effects of reuse and bleach/formaldehyde reprocessing on polysulfone and polyamide hemodialyzers

The surface features, morphology, and blood interactions of fibers from pristine, bleach/formaldehyde reprocessed, and reused Fresenius Polysulfone High Flux (Hemoflow F80B) hemodialyzers and Gambro Polyflux 21S Polyamide hemodialyzers have been studied. SEM images of fibers from both hemodialyzer types revealed a dense skin layer on the inner surface and a relatively thick porous layer on the outer surface. The 21S polyamide support layer consisted of interconnected highly porous structures. Environmental scanning electron microscopy and atomic force microscopy images of both membrane types showed alterations in morphology due to reprocessing and reuse; however the changes were more marked for the 21S polyamide dialyzers. Fluorescence microscopy images showed only minimal fluorescence associated with the fibers after patient use and reprocessing, suggesting that blood derived deposits were removed by processing. The protein layers formed on pristine and reused hemodialyzer membranes during clinical use were studied using SDS-PAGE and immunoblotting. Before bleach/formaldehyde treatment, protein layers of considerable amount and complexity were found on the blood side of singly and multiply used dialyzers. Proteins adsorbed on the dialysate side were predominantly in the molecular mass region below 30 kDa. However, some higher molecular mass proteins were detected on the dialysate side of the 21 S polyamide dialyzers. Very little protein was detected on dialyzers that were treated with bleach/formaldehyde after dialysis, regardless of whether they had been used/reprocessed once or 12 times.     

Studies concerning the structure and organization of the vaccinia virus nucleoid. I. Isolation and characterization of subviral particles prepared by treating virions with guanidine-HCL, nonidet-P40, and 2-mercaptoethanol

Subviral particles (Gu-subviral particles) containing DNA complexed with 20–25% of the protein found in complete virus particles could be isolated after treating purified vaccinia virions with 8 M guanidine-HCI, 1% Nonidet-P40, and 1% 2-mercaptoethanol. Electron microscopic examination of the Gu-subviral particles fixed with glutaraldehyde and formaldehyde, revealed spherical structures, 300–350 nm in diameter. DNA in combination with protein was observed to be further folded into globular structures, 200–600 Å in diameter on the surface of the particles. Analysis of the proteins in Gu-subviral particles by SDS-polyacrylamide gel electrophoresis showed that 10 polypeptides with molecular weights of 120K, 90K, 68K, 61K, 58K, 32K, 27K, 24K, 14.5K, and 10K were associated with the viral DNA. After dialysis, the particles could be shown to have retained, in part, the capacity to catalyze the synthesis of RNA in vitro.     

Conjugation of DNA fragments to protein carriers by glutaraldehyde: immunogenicity of oligonucleotide-hemocyanin conjugates

The practical realization of the concept of specific immunotherapy for systemic lupus erythematosus (SLE) has been hampered, thus far, by an inability to link DNA fragments to carrier protein. In this paper, a novel technique is described, in which glutaraldehyde is the linking agent. A 2-stage method was used to link oligonucleotides to a soluble protein carrier, such as keyhole limpet hemocyanin (KLH) or human gamma globulin (HGG), whereas a 1-stage technique was sufficient to link oligonucleotides to sheep red cells. Both the ultraviolet absorbance spectrum and diphenylamine assay demonstrated that oligonucleotides were coupled to soluble protein. The conjugate of oligonucleotide to protein carrier appears to be recognized by anti-DNA antibody since oligonucleotide linked to either KLH or HGG inhibited the binding of anti-DNA antibody in vitro, and oligonucleotide-coupled sheep cells are agglutinating by seropositve sera from lupus patients. In addition, oligonucleotide-KLH raised hemagglutinating antibody to denatured DNA in C57BL/6, DBA/2 or NZB mice, as well as IgG antibody as detected by SPRIA in C57BL/6 and DBA/2 mice. The significance of this new method for the development of an antigen specific therapy of SLE is discussed.