Controversial role of antibodies against linear epitopes of desmoglein 3 in pemphigus vulgaris, as revealed by semiquantitative living cell immunofluorescence microscopy and in-cell ELISA

Tacrolimus reverses pemphigus vulgaris serum-induced depletion of desmoglein in HaCaT cells via inhibition of heat shock protein 27 phosphorylation

BACKGROUND

Glucocorticoids are the first-line treatment for Pemphigus vulgaris (PV), but its serious side effects can be life-threatening for PV patients. Tacrolimus (FK506) has been reported to have an adjuvant treatment effect against PV. However, the mechanism underlying the inhibitory effect of FK506 on PV-IgG-induced acantholysis is unclear.

OBJECTIVE

The objective of this study was to explore the effect of FK506 on desmoglein (Dsg) expression and cell adhesion in an immortalized human keratinocyte cell line (HaCaT cells) stimulated with PV sera.

METHODS

A cell culture model of PV was established by stimulating HaCaT cells with 5% PV sera with or without FK506 and clobetasol propionate (CP) treatment. The effects of PV sera on intercellular junctions and protein levels of p38 mitogen-activated protein kinase (p38MAPK), heat shock protein 27 (HSP27), and Dsg were assayed using western blot analysis, immunofluorescence staining, and a keratinocyte dissociation assay.

RESULTS

PV sera-induced downregulation of Dsg3 was observed in HaCaT cells and was blocked by FK506 and/or CP. Immunofluorescence staining revealed that linear deposits of Dsg3 on the surface of HaCaT cells in the PV sera group disappeared and were replaced by granular and agglomerated fluorescent particles on the cell surface; however, this effect was reversed by FK506 and/or CP treatment. Furthermore, cell dissociation assays showed that FK506 alone or in combination with CP increased cell adhesion in HaCaT cells and ameliorated loss of cell adhesion induced by PV sera. Additionally, FK506 noticeably decreased the PV serum-induced phosphorylation of HSP 27, but had no effect on p38MAPK phosphorylation.

CONCLUSION

FK506 reverses PV-IgG induced-Dsg depletion and desmosomal dissociation in HaCaT cells, and this effect may be obtained by inhibiting HSP27 phosphorylation.

Photodynamic Therapy (Association Diode Laser/Hydrogen Peroxide): Evaluation of Bactericidal Effects on Periodontopathy Bacteria: An in Vitro Study

The main cause for the development of periodontitis is the accumulation of subgingival microbial deposits organized tightly to the porous surface of the tooth cementuni. The growth of the microbial populations and the immunological reaction of the host organism are responsible for the destruction of periodontal ligament apparatus. The primary goal in the treatment of periodontitis is the complete removal of subgingival bacterial deposits. The large amount of evidence establishing a microbial etiology for periodontitis (has been the basis for the development of antimicrobial treatment approaches. Photodynamic therapy (PDT) employs a non-toxic dye, termed a photosensitizer (PS), and low intensity visible light which, in the presence of oxygen, combine to produce cytotoxic species. In this in vitro protocol study it was tested the bactericidal efficacy of Diode laser (Oralia), of Hydrogen Peroxyde and the association Diode Laser-Peroxyd Hydrogen (PDT) on Prevotella intermedia, Peptostreptococcus micros and Fusobacterium nucleatum, three of the most aggressive bacteria envolved on periodontal disease.

The Use of Laser Diodes Superpulses in Implantology

Diode laser is a laser, usually between 810 and 980 nm wavelength, able to work on hard and soft tissues, as periodontal tissues and bone. The use of Diode laser is recommended during oral surgery or periodontal therapy, when it is necessary to erase any periodontal bacteria evolved in periodontal disease, in combination with hydrogen peroxide (photodynamic therapy), and also, by its biostimulating effects, to improve the healing of the regenerative procedures, as sinus lift, bone crestal expansion or to assist implant surgery. This article shows two cases report in which diode lasers are evolved. Diode lasers in association with Hydrogen Peroxide on utilizing the decontaminant effects oh Photodynamic Therapy, and to prepare the area defects for a regenerative surgery.

Mapping of B cell epitopes on desmoglein 3 in pemphigus vulgaris patients by the use of overlapping peptides

BACKGROUND

Pemphigus vulgaris (PV) is a severe autoimmune blistering disease associated with autoantibodies to desmoglein 3 (Dsg 3), a transmembrane glycoprotein of the cadherin family. Previous studies mainly focused on the mapping of conformational epitopes of Dsg 3 using recombinant fragments of Dsg 3 and competition ELISA.

OBJECTIVE

Here, we performed a mapping of linear B cell epitopes on Dsg 3 in PV patients by the use of overlapping synthetic peptides.

METHODS

A set of 254 overlapping synthetic peptides of 14 amino acids length covering the entire Dsg 3 extracellular domain was generated. Sera of patients with active PV (n=10) and healthy volunteers (n=10) were tested for IgG reactivity with the 254 peptides by ELISA. Testing each peptide separately, 7 major antigenic sites were identified. In order to validate these reactivities, 7 corresponding peptides of 13-33 amino acids in length were generated and employed by ELISA. Additional sera of active PV patients (n=17) and healthy volunteers (n=20) were tested and the most reactive peptide was used to specifically purify anti-Dsg 3 antibodies from PV sera (n=3).

RESULTS

The major autoantibody reactivity in PV sera was mapped to amino acids 333-356 within the EC3 domain. Purifying patients IgG using the identified peptide, however, failed to induce acantholysis in keratinocyte dissociation assay.

CONCLUSION

We conclude that linear epitopes do not play a major pathogenic role in human PV.

Prediction of B-cell linear epitopes with a combination of support vector machine classification and amino acid propensity identification

Epitopes are antigenic determinants that are useful because they induce B-cell antibody production and stimulate T-cell activation. Bioinformatics can enable rapid, efficient prediction of potential epitopes. Here, we designed a novel B-cell linear epitope prediction system called LEPS, Linear Epitope Prediction by Propensities and Support Vector Machine, that combined physico-chemical propensity identification and support vector machine (SVM) classification. We tested the LEPS on four datasets: AntiJen, HIV, a newly generated PC, and AHP, a combination of these three datasets. Peptides with globally or locally high physicochemical propensities were first identified as primitive linear epitope (LE) candidates. Then, candidates were classified with the SVM based on the unique features of amino acid segments. This reduced the number of predicted epitopes and enhanced the positive prediction value (PPV). Compared to four other well-known LE prediction systems, the LEPS achieved the highest accuracy (72.52%), specificity (84.22%), PPV (32.07%), and Matthews' correlation coefficient (10.36%).