Cytotoxic mAb from Rheumatic Carditis Recognizes Heart Valves and Laminin

Anti-streptococcal antibodies cross-reactive with N-acetyl-bD-glucosamine (GlcNAc) and myosin are present in the sera of patients with rheumatic fever (RF). However, their role in tissue injury is not clear. In this study, we show that anti-GlcNAc/anti-myosin mAb 3.B6 from a rheumatic carditis patient was cytotoxic for human endothelial cell lines and reacted with human valvular endothelium and underlying basement membrane. Reactivity of mAb 3.B6 with the valve was inhibited by human cardiac myosin \u3e laminin \u3e GlcNAc. The mAb 3.B6 epitopes were localized in fragments of human cardiac myosin, including heavy meromyosin (HMM), the S1 subfragment, and two light meromyosin (LMM) peptides containing amino acid sequences KEALISSLTRGKLTYTQQ (LMM 1) and SERVQLLHSQNTSLINQK (LMM 33). A novel feature of mAb 3.B6 was its reactivity with the extracellular matrix protein laminin, which may explain its reactivity with the valve surface. A laminin A-chain peptide (HTQNT) that includes homology to LMM33 inhibited the reactivity of mAb 3.B6 with human valve. These data support the hypothesis that cross-reactive antibodies in rheumatic carditis cause injury at the endothelium and underlying matrix of the valve

Antibodies Elicited in Response to EBNA-1 May Cross-React with dsDNA

Several genetic and environmental factors have been linked to Systemic Lupus Erythematosus (SLE). One environmental trigger that has a strong association with SLE is the Epstein Barr Virus (EBV). Our laboratory previously demonstrated that BALB/c mice expressing the complete EBNA-1 protein can develop antibodies to double stranded DNA (dsDNA). The present study was undertaken to understand why anti-dsDNA antibodies arise during the immune response to EBNA-1.In this study, we demonstrated that mouse antibodies elicited in response to EBNA-1 cross-react with dsDNA. First, we showed that adsorption of sera reactive with EBNA-1 and dsDNA, on dsDNA cellulose columns, diminished reactivity with EBNA-1. Next, we generated monoclonal antibodies (MAbs) to EBNA-1 and showed, by several methods, that they also reacted with dsDNA. Examination of two cross-reactive MAbs--3D4, generated in this laboratory, and 0211, a commercial MAb--revealed that 3D4 recognizes the carboxyl region of EBNA-1, while 0211 recognizes both the amino and carboxyl regions. In addition, 0211 binds moderately well to the ribonucleoprotein, Sm, which has been reported by others to elicit a cross-reactive response with EBNA-1, while 3D4 binds only weakly to Sm. This suggests that the epitope in the carboxyl region may be more important for cross-reactivity with dsDNA while the epitope in the amino region may be more important for cross-reactivity with Sm.In conclusion, our results demonstrate that antibodies to the EBNA-1 protein cross-react with dsDNA. This study is significant because it demonstrates a direct link between the viral antigen and the development of anti-dsDNA antibodies, which are the hallmark of SLE. Furthermore, it illustrates the crucial need to identify the epitopes in EBNA-1 responsible for this cross-reactivity so that therapeutic strategies can be designed to mask these regions from the immune system following EBV exposure

Antiinflammatory effects of essential oil from the leaves of Cinnamomum cassia and cinnamaldehyde on lipopolysaccharide-stimulated J774A.1 cells

Cassia oil (CO) from different parts of Cinnamomum cassia have different active components. Very few pharmacological properties of cassia leaf oil have been reported. This study investigated and compared effects of cassia leaf oil and cinnamaldehyde on lipopolysaccharide (LPS)-activated J774A.1 cells. Volatile compositions in cassia leaf oil were identified by gas chromatography-mass spectrometry (MS)/MS. Effects of CO and cinnamaldehyde on LPS-activated J774A.1 cells were investigated by determining nitric oxide (NO) production using Griess reaction assay; expression of pro-inflammatory cytokines, enzymes involve in inflammatory mediators; antiinflammatory cytokines, and iron exporter ferroportin1 (Fpn1) using reverse transcription-polymerase chain reaction; and production of tumor necrosis factor (TNF-α) and interleukin (IL)-10 using ELISA. The main component of CO was cinnamaldehyde. Both oils at 1-20 μg/ml markedly inhibited NO production in LPS-activated J774A.1 cells with IC 50 value of 6.1 ± 0.25 and 9.97 ± 0.35 μg/ml, respectively. They similarly inhibited mRNA expression of pro-inflammatory cytokines and chemokines. These mediators included TNF-α, IL-1β, IL-6, monocyte chemoattractant protein-1, and macrophage inflammatory protein-1α in LPS-activated cells. They also significantly decreased expression of inducible enzymes inducible nitric oxide synthase, cyclooxygenase-2, microsomal prostaglandin-E synthase-1. In the opposite way, they increased mRNA expression and the production of antiinflammatory cytokines IL-10 and transforming growth factor-β. In addition, they promoted the expression of Fpn1. These results demonstrated that inhibitory effects of cassia leaf oil from C. cassia mainly came from cinnamaldehyde. This compound not only inhibited inflammatory mediators but also activated antiinflammatory mediators in LPS-activated J774A.1 cells. It may also have an effect on iron regulatory proteins in activated macrophages

In vitro anti-inflammatory, mutagenic and antimutagenic activities of ethanolic extract of Clerodendrum paniculatum root

Clerodendrum paniculatum L. (Family Verbenaceae) has been used as an antipyretic and anti-inflammatory drug in traditional Thai medicine. This present study investigated the in vitro anti-inflammatory, mutagenic and antimutagenic activities of the ethanolic extract of C. paniculatum (CPE) dried root collected from Sa Kaeo Province of Thailand. Murine macrophage J774A.1 cells were stimulated by lipopolysaccharide (LPS) to evaluate nitric oxide (NO), tumor necrosis factor-α (TNF-α) and prostaglandin E 2 (PGE 2 ) production in the anti-inflammatory test while the mutagenic and antimutagenic potential was performed by the Ames test. The outcome of this study displayed that the CPE root significantly inhibited LPS-induced NO, TNF-α, and PGE 2 production in macrophage cell line. In addition, the CPE root was not mutagenic toward Salmonella typhimurium strain TA98 and TA100 with and without nitrite treatment. Moreover, it inhibited the mutagenicity of nitrite treated 1-aminopyrene on both strains. The findings suggested the anti-inflammatory and antimutagenic potentials of CPE root