Ildikó Sonkoly

Enzyme-linked immunosorbent assay for antibodies to native DNA in sera of patients with SLE

A micro-ELISA technique has been developed to measure antibodies to native DNA and used in SLE patients. The distribution of antibody to native DNA in the main immunoglobulin classes was studied, using anti-human globulin conjugates labelled with peroxidase. the antigen (double-stranded DNA from calf thymus) used in the assay was adsorbed to the surface of polystyrene plates treated with methylated bovine serum albumin. The standardization of the method was carried out by use of globulin calibration curves.

Circulating immune complexes and monocyte Fc function in autoimmune diseases.

The phagocytosis of separated and adherent monocytes of patients with systemic lupus erythematosus is subnormal as compared to controls on the basis of latex and yeast uptake. The monocytes from the same patients react with antibody-coated sheep red blood cells in a significantly higher degree than normal monocytes. There is a correlation between the percentage of reactive monocytes and the serum immune complex content. After brief treatment of patients with levamisole the phagocytic function of monocytes is restored and at the same time the circulating immune complex content is decreased.

Immunological Investigations in Acute and Chronic Human Pancreatitis

Follow-up immunological studies in 27 patients with acute pancreatitis of known etiology showed a significant elevation in the level of circulating immune complexes (IC), a significant inhibition in migration of leukocytes (with direct LMT) of patients and a significant decrease in the percentage of T-active, T-total peripheral lymphocytes and in the absolute count of peripheral T cells. Elevated circulating IC levels could been detected 3-4 weeks after the onset of acute pancreatitis. These immunological changes have still been demonstrated in a number of patients 7-14 months after recovery. We have found similar immunological alterations in patients with chronic pancreatitis as well. The possible causes and role of these long-term existing immunologic abnormalities are discussed.

Stimulating effect of tuftsin and its analogues on the defective monocyte chemotaxis in systemic lupus erythematosus

Monocytes and macrophages are engaged at various levels of cellular immune reactivity. In addition to their function in the defensive mechanism directed at infective agents, they also play a basic role in immune complex elimination and antigen handling. Previous experiments revealed that systemic lupus erythematosus (SLE), the main representative of the autoimmune diseases, is associated with impaired monocyte chemotaxis. The endogenous basic tetrapeptide tuftsin and 6 of its analogues were examined in vitro for their stimulating capacity on the chemotactic responsiveness of monocytes derived from patients with SLE. The monocyte migration assay was carried out by a modified Boyden technique and quantified by the leading front distance method and by counting the total distance covered by the monocyte locomotion. Tuftsin and 3 of its analogues significantly increased the defective chemotaxis in SLE. The tetrapeptides effective on chemotaxis also stimulated random migration and phagocytosis of the monocytes, albeit to a lesser extent. Structure-activity relationships, as well as the influence of the clinical stage of the disease were also examined. Experimental evidence leads to a favourable prediction for the immunotherapeutic value of these oligopeptides for the control of infections and the progression of the disease in patients with systemic lupus erythematosus.

The antigen/receptor specificity of antigranulocyte antibodies in patients with SLE

The antigen/receptor specificity of antigranulocyte antibodies (AGAs) detected in the sera of patients with systemic lupus erythematosus (SLE) was investigated by inhibitory immunofluorescence test and Western immunoblotting technique. The interactions of AGAs with antigens of intact normal granulocytes were determined by inhibiting the binding of different myeloid monoclonal antibodies (mAbs). Seven of the studied 12 sera revealed binding to CD15 (X hapten) and/or to CD16 (FcR1o). The specificity investigation of AGAs was completed with Western immunoblotting technique. The binding of AGAs to bands with Mr of about 50-60 kDa and at 30 kDa on unstimulated granulocyte plasma membrane preparation could be demonstrated from 4 out of 6 AGA positive SLE sera. The cause of the disappearance of bands on the phorbol-myristate-acetate (PMA) activated membrane except those of the 50-60 kDa bands is still to be discovered.

Effects of immune complexes from SLE patients on human monocyte locomotion and Fc receptor function.

The effect of immune complexes (IC) isolated from systemic lupus erythematosus (SLE) sera with polyethylene glycol and gel filtration on the chemotaxis and Fc receptor function of healthy monocytes was examined. Even at a low protein concentration (1 microgram/ml = 1 mg/l) ICs inhibit monocyte chemotaxis. ICs from patients with SLE nephritis are more inhibitory than ICs from patients without renal disease. The inhibitory effects of ICs on monocyte chemotaxis and Fc receptor activity are similar, suggesting a relationship between the chemotactic and Fc receptor function of monocytes. Analysis of the ICs by enzyme-linked immunoassay showed no correlation between the quantity of IgG, C3, and anti-DNA in the IC samples and their effects on monocyte function.

Subset specificity of lupus antilymphocyte antibodies studied by two-colour microfluorimetry

Subset specific lymphocytotoxic activity of lupus sera was studied by a combination of selective immunofluorescence labelling and complement-mediated lysis. Most frequently death of B cells was detected. Many of the sera caused lysis of T lymphocytes; selective cytotoxicity against suppressor T cells could be observed less frequently. All the anti-T4, anti-T8 and anti-B lymphocyte antibodies proved to be cold reactive.

Monocyte Activation by Immune Complexes of Patients with SLE

1. IC precipitated by PEG from patients with SLE inhibit in vitro the FcR dependent reaction of normal monocytes with sSRBC, while the C3bR dependent reaction of the cells with sensitized yeast is reduced only by some of them. The monocytes were preincubated with the IC for 30 min at room temperature. 2. When the monocytes were incubated with the IC for 22 hours at 37 degrees C the reaction of FcR with sSRBC increased, while the C3bR dependent reaction did not altered. 3. Simultaneously with the increasing FcR dependent reaction, the secretion of lysosomal beta-glucuronidase of monocytes cultivated with IC is greater than those of the controls.

Studies on the lymphocyte subpopulation in systemic lupus erythematosus by monoclonal antibodies

T cells and T-cell subsets were studied with monoclonal antibodies in 15 patients with systemic lupus erythematosus (SLE) during a 6-wk period. During active states of disease, all investigated T-cell subsets decreased, but the reduction of suppressor cells seemed to be more pronounced, therefore the helper/suppressor ratio increased. Less suppressor cells could be detected during clinical impairments and more during improvements.