Anti‐histone H1 IgGs from blood serum of systemic lupus erythematosus patients are capable of hydrolyzing histone H1 and myelin basic protein

Abstract

Novel hydrolytic activity of the anti-histone H1 antibodies (Ab) toward histone H1 and myelin basic protein (MBP) was shown. Blood serum of ten patients with clinically diagnosed systemic lupus erythematosus (SLE), and nine healthy donors (control) were screened for the anti-histone H1 antibody- and anti-MBP antibody-mediated specific proteolytic activity. IgGs were isolated by chromatography on Protein G-Sepharose, and four of ten SLE patients appeared to possess IgGs that were capable of cleaving both histone H1 and MBP. Such activity was confirmed to be an intrinsic property of the IgG molecule, since it was preserved at gel filtration at alkaline and acidic pH. At the same time, proteolytic activity was absent in the sera-derived Ab of all healthy donors under control. Anti-histone IgGs were purified by the affinity chromatography on histone H1-Sepharose. Their cross-reactivity toward cationic proteins (histones, lysozyme, and MBP) and their capability of hydrolyzing histone H1 and MBP were detected. However, these IgGs were not cleaving core histones, lysozyme, or albumin. Capability of cleaving histone H1 and MBP was preserved after additional purification of anti-histone H1 IgGs by the HPLC gel filtration. The protease activity of anti-histone H1 IgG Ab was inhibited by serine protease inhibitors.

Histone H1/MBP hydrolysing antibodies - novel potential marker in diagnosis of disease severity in systematic lupus erythematosus patients

“…Antibodies possessing similar proteolytic activity were found in blood serum of multiple myeloma and multiple sclerosis patients [15,16]. We have shown that these proteolytically active AB can be classified as anti-histone auto-AB [17]. We also hypothesized that such AB could be responsible for the development of health disorders in SLE patients.…”

“…Isolation of IgG from blood serum was performed, as described earlier [17]. 2 ml of blood serum were precipitated with ammonium sulfate (50% saturation).…”

“…Protease activity of IgG preparations was tested as described [17]. Commercial bovine basic protein (Sigma, USA) and calf thymus histone H1 (Axxora, Germany) were used as substrates for proteolysis.…”

Proteolytic activity of IgG-antibodies of mice, immunized by calf thymus histones

“…У той самий час ці ж антитіла були неактивні щодо гідролізу решти протеїнових субстратів (лізоцим, ци-тохром с, макроглобулін, казеїн, овальбумін, БСА). Необхідно відмітити, що подібну суб-стратну специфічність було виявлено також у протабзимів, виділених із сироватки крові хворих на СЧВ [17,26,29] та із молока дея- еКСПеРиМеНТАЛьНІ РОБОТи ких клінічно здорових жінокпороділь [26]. На відміну від протабзимів сироватки крові хво-рих на СЧВ, афінно очищені IgGантитіла си-роватки крові імунізованих мишей мали високу протеолітичну активність щодо корових гістонів тимуса теляти.…”

Sialylation of anti-histone antibodies in blood serum of systemic lupus erythematosus patients

“…Колонку промивали ТБС, pH 7,5. Фракцію білків зі спорідненістю до сорбен-ту елюювали 3M NaCl, діалізували впродовж 18 год проти ТБС і антигістонові IgG-антитіла додатково очищали хроматографією на колонці із протеїн G-сефарозою згідно з [16]. IgG елюювали 0,1 М гліцин-НСІ, рН 2,6 і нейтралізували 1,5 М трис-HCl, pH 8,8, після чого АТ діалізували проти 20 мМ трис-HCl, pH 7,5 протягом 18 год.…”