S. Olszowski

Enhancement of immunogenic properties of ovalbumin as a result of its chlorination

1. Chlorination of ovalbumin results in its enhanced immunogenic properties. 2. This has been evaluated by the interleukin-2 production after incubation of the modified protein with antigen presenting cells and T helper cells.

Enhancement of proteinase-mediated degradation of proteins modified by chlorination

1. Pretreatment of some proteins (albumin, immunoglobulin G, elastin and fibrinogen) with hypochlorite or with the MPO-H2O2-Cl- system increased their susceptibility to proteolysis by trypsin, chymotrypsin or elastase. 2. The optimal activities of these three proteinases were attained at a different extent of albumin chlorination. 3. Elastase was found to develop a specially efficient activity towards chlorinated albumin or chlorinated elastin being by itself resistant to chlorinating species.

A possible origin of chemiluminescence in phagocytosing neutrophils reaction between chloramines and H2O2

A mixture of chloramines and hydrogen peroxide emits light. It was found that the reaction between taurine monochloramine and hydrogen peroxide is very slow. The stoichiometry of the reaction is 1:1 and taurine is detected as one of the products. The chlorinated proteins and bacteria, containing N-Cl groups, when reacting with hydrogen peroxide, are more effective in emitting light than low-molecular chloramines. Luminol enhances considerably light yield of the chloramine-hydrogen peroxide reaction. The chloramine-H2O2 reaction may account for light emitted by neutrophils during phagocytosis.

A possible origin of chemiluminsecence in phagocytosing neutrophils. Myeloperoxidase-mediated chlorination of proteins and tryptophan

Chlorination of proteins by the myeloperoxidase-H2O2-Cl- system results in light emission. Out of all amino acids present in proteins only tryptophan delivers light during chlorination. Chlorination of tryptophan by the myeloperoxidase-H2O2-Cl- system, as well as by HOCl or taurine chloramine is associated with chemiluminescence. pH dependence and time pattern of light emission is similar for chlorination of tryptophan by the myeloperoxidase system and taurine, but appears to be different for chlorination by HOCl. Aerobic conditions are necessary for chemiluminescence of chlorinated tryptophan.

Sulphoacetaldehyde as a product of taurine chloramine peroxidation at site of inflammation.

Summary. It has been reported, that sulphoacetalhehyde is formed in the fagocytozing PMNs and its production is taurine monochloramine mediated. Since H2O2 and secreted MPO are present in the medium the non- and enzymatic peroxidation of taurine of its mono- and dichloramines were examined within the pH range 5.3–7.4. The formation of sulphoacetaldehyde was observed in nonenzymatic hydrolysis of taurine N,N-dichloramine (pH 5.3) as well as for monochloramine at pH 7.4. It was found also that its formation was accelerated in the presence of H2O2, in the MPO/H2O2 and in the full system containing Cl−. Additionally it was shown that also horseradish peroxidase (HRP) could catalyze sulphoacetaldehyde production. The sulphoacetaldehyde formation in the examined systems was confirmed with the use of 1HNMR spectra of separated 2,4-dinitrophenylhydrazone derivative. Our results suggest that both non- and ezymatic processes could contribute to the sulphoacetaldehyde formation at site of inflammation.

Chemiluminescence of ABEI-labelled IgG triggered by the N-chloramine–H2O2–p-iodophenol system

Light is emitted in systems containing N-chloramines or hypochlorite, H(2)O(2) and N-(4-aminobutyl)-N-ethylisoluminol (ABEI). The emission is enhanced by 4-iodophenol (PIP) in alkaline solution (1 mol/L NaOH), while at lower pH range (9-11) PIP is not only inactive but also its presence reduces chemiluminescence (CL) of the monochloramine-H(2)O(2)-ABEI system to the background. Two procedures for ABEI-labelled IgG assays were developed, with PIP in 1 mol/L NaOH and without PIP at pH 11, and the standard curves of free ABEI in these conditions were examined. We suggest also that the oxidative deamination of taurine chloramine leads to the formation of the various carbonyl derivatives and their formation is accelerated in the presence of H(2)O(2), especially in less alkaline solutions (pH 11). Moreover, the formation of enol forms of aldehydes in assay buffers was observed. The yield of the phenoxy radical mediators of ABEI oxidation and the pH-dependent H(2)O(2):HO(2) ratio seems to be decisive for the overall CL in the system examined. The main advantage of this method is that CL does not need precise timing of measurements and assays can be performed over a long period of time (hours) using a plate luminometer.