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EN
Propionibacterium acnes (PA) and Staphyloccocus epidermidis (SE) are two major bacterial strains isolated from acne lesions. Nevertheless, only PA seems to be implicated in the pathogenesis of inflammatory acne vulgaris. Evidence for this, however, remains indirect and the precise role of PA in inflammatory acne is still a matter for conjecture. The aim of this study was to compare some pro-inflammatory and adjuvant properties of PA and SE. To determine some of the pathogenic, immunostimulatory, and pro-inflammatory properand ties of PA and SE, two experimental models of inflammation were used. In vivo; chronic inflammation was induced by intradermal injection of living bacteria into the ear. In vitro; peritoneal macrophages elicited by the bacteria were examined for their ability to generate reactive oxygen species (ROS), nitric oxide (NO), and cytokines. PA, but not SE, evoked mild local inflammation of infected ears. Macrophages elicited with PA produced more tumor necrosis factor ? and interleukin IL-12 than those induced with SE, while SE was a stronger inducer of IL-10 production. Both bacteria equally induced the generation of NO and ROS. In contrast, only PA showed adjuvant properties. The results of these studies indicate that SE, in contrast to PA, does not exert pro-inflammatory properties. Thus it is unlikely that SE may be implicated in the pathogenesis of inflammatory acne vulgaris.
EN
Atomic force spectroscopy was used to study interaction strengths between bacterial antigens and receptors on macrophages. This method allowed for a direct comparison of the interaction strengths in different systems studied at the level of single molecules.
EN
Introduction: Taurine chloramine (TauCl) and taurine bromamine (TauBr) are the main haloamines produced by activated neutrophils. TauCl exerts both anti-inflammatory and microbicidal activities. Clinical studies showed that TauCl may be useful as an antimicrobial agent in the local treatment of infections. Much less is known about TauBr. Circumstantial evidence suggests that Propionibacterium acnes (PA) has a role in the inflammation of acne. Available topical therapies include antimicrobial agents which reduce total PA numbers and anti-inflammatory agents which suppress activity of the cells present in acne inflammatory lesions. In this study the bactericidal activities of TauBr and TauCl against PA and Staphylococcus epidermidis (SE), as a control strain, were investigated. Moreover, the influence of these haloamines on the generation of reactive oxygen species (ROS) by activated neutrophils was also tested. Materials and Methods: TauBr and TauCl were prepared by reaction of taurine with HOBr and HOCl, respectively. The reaction was monitored by UV absorption spectra. The bactericidal activities of TauBr and TauCl were determined by the pour-plate method. The generation of ROS by neutrophils was determined by luminol chemiluminescence assay. Results: In our experimental set-up, TauBr showed stronger antibacterial activity than TauCl. Interestingly, PA was significantly more susceptible to TauBr than SE was. Moreover, TauBr at non-cytotoxic concentrations significantly reduced ROS generation by neutrophils.Conclusions: Since PA is considered to be an etiological agent in acne and ROS are closely correlated with the pathogenesis of inflammatory skin diseases, the reported data suggest that TauBr may be a good candidate for the topical therapy for acne vulgaris.
EN
1-Methylnicotinamide (MNA), a major metabolite of nicotinamide (NA), is known to exert anti-inflammatory effects in vivo. Treatment of inflammatory skin diseases by topical application of MNA provides certain advantages over the use of NA. However, in contrast to NA, the molecular mechanisms of the anti-inflammatory properties of MNA are not well known. In this study the influence of exogenous MNA and NA in vitro on the generation of inflammatory mediators by macrophages (Mo) was investigated. Materials and Methods: Peritoneal Mo of CBA/J mice were activated in vitro with lipopolysaccharide and incubated with MNA or NA. The effect of these compounds on biological functions of Mo was measured by evaluation of the production of reactive oxygen species (ROS) by luminol-dependent chemiluminescence, cytokines and prostaglandin E2 (PGE2) by ELISA, and nitric oxide (NO) by the Griess method. Moreover, the expressions of inducible NO synthase and cyclooxygenase-2 were measured by Western blotting. Results: It was shown that at non-cytotoxic concentrations, NA inhibits the production of a variety of pro-inflammatory agents, such as tumor necrosis factor alpha interleukin 6, NO, PGE2, and the generation of ROS. In contrast to NA, exogenous MNA inhibited only the generation of ROS, while its effect on the synthesis of other mediators was negligible. Conclusions: These results indicate that the anti-inflammatory properties of MNA demonstrated previously in vivo do not depend on its capacity to suppress the functions of immune cells, but more likely may be related to its action on vascular endothelium. The authors suggest that the limited permeability for exogenous MNA, in contrast to that for NA, may be responsible for its lack of suppressor activity against Mo.
EN
Oxidative modification of proteins affects their biological properties. Previously we have shown that hypochlorite (HOCl), the product of activated neutrophils, enhances protein immunogenecity. Collagen type II, a primary component of cartilage, is commonly used in the induction of arthritis in animals (CIA). The aim of this study was to examine whether HOCl may affect immunogenic, tolerogenic, and arthritogenic properties of collagen. DBA/J mice were injected with either native (CNAT) or chlorinated collagen (CHOCl) to induce arthritis. The effect of chlorination on collagen properties was measured by evaluation of incidence and severity of CIA. Moreover, the concentration of serum anti-collagen IgG antibodies and myeloperoxidase (MPO) activity in inflamed joints was determined. Mice immunized with CNAT in adjuvant developed arthritis (CIA) with an incidence of 69%. CNAT also exerted tolerogenic properties when injected intravenously either before or shortly after primary immunization, resulting in decreased incidence and severity of CIA, reduced MPO activity in inflamed joints, and lowered serum levels of anti-CNAT IgG antibodies. Chlorination of collagen significantly diminished its ability to induce CIA and to trigger generation of anti-CNAT IgG antibodies. Interestingly, chlorination did not affect tolerogenic properties of collagen administered prior to primary immunization with CNAT. These results suggest that chlorination of collagen may selectively affect functional epitopes of collagen. It is likely that in inflamed joints, neutrophil-derived HOCl, in some circumstances, will destroy arthritogenic and immunogenic B cell epitopes, while regulatory T cell epitopes will be preserved.
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