The Effects of Staphylococci on the Degranulation of Human Mast Cell-1

Atopic dermatitis (AD) is characterized by disturbances in epidermal barrier functions and the hyperactive immune response. Staphylococcus aureus (S. aureus) can be cultured from 90% of AD skin lesions and can exacerbate or contribute to the persistent skin inflammation in AD by secreting toxins with superantigenic properties. Superantigens can induce mast cell (MC) degranulation after penetrating the epidermal barrier. The role of MCs in AD is suggested by the increase in the MC number and MC activation. MCs are activated for degranulation and mediator release by allergens that cross-link IgE molecules or by microbial products. Therefore, MCs may be critically involved in the pathogenesis of AD. However, the understanding mechanisms of MC degranulation by S. aureus in relation to AD have still not been fully elucidated. In this study, we found that live S. aureus or methicillin-resistant S. aureus (MRSA) but not heat-killed bacteria induced MC degranulation. The heat-treatment partially inhibited MC degranulation by conditioned media (CM) of S. aureus or MRSA. The calcium chelator ethylene glycol tetraacetic acid (EGTA) did not block MC degranulation induced by live S. aureus or MRSA, but EGTA-treatment partially inhibited MC degranulation by CM from S. aureus or MRSA. These results suggest that live S. aureus and MRSA can degranulate MCs via direct interaction which may be important role in AD.

The Effects of Staphylococci on the Degranulation of Human Mast Cell-1

Atopic dermatitis (AD) is characterized by disturbances in epidermal barrier functions and the hyperactive immune response. Staphylococcus aureus (S. aureus) can be cultured from 90% of AD skin lesions and can exacerbate or contribute to the persistent skin inflammation in AD by secreting toxins with superantigenic properties. Superantigens can induce mast cell (MC) degranulation after penetrating the epidermal barrier. The role of MCs in AD is suggested by the increase in the MC number and MC activation. MCs are activated for degranulation and mediator release by allergens that cross-link IgE molecules or by microbial products. Therefore, MCs may be critically involved in the pathogenesis of AD. However, the understanding mechanisms of MC degranulation by S. aureus in relation to AD have still not been fully elucidated. In this study, we found that live S. aureus or methicillin-resistant S. aureus (MRSA) but not heat-killed bacteria induced MC degranulation. The heat-treatment partially inhibited MC degranulation by conditioned media (CM) of S. aureus or MRSA. The calcium chelator ethylene glycol tetraacetic acid (EGTA) did not block MC degranulation induced by live S. aureus or MRSA, but EGTA-treatment partially inhibited MC degranulation by CM from S. aureus or MRSA. These results suggest that live S. aureus and MRSA can degranulate MCs via direct interaction which may be important role in AD.

Effects of Total Saponins of Chaenomeles speciosa on Degranulation Ratio of RBL-2H3 Mast Cells / 医药导报

Objective To study the effects of total saponins of Chaenomeles speciosa on release of β-hexosaminidase from rat basophilic leukemia-2H3 ( RBL-2H3 ) mast cells. Methods After rat RBL-2H3 mast cells were prepared, total saponins of Chaenomeles speciosa and the RBL-2H3 mast cells were co-cultured.The toxic effects of total saponins of Chaenomeles speciosa on mast cells were detected by MTT method, β-hexosaminidase release rate was measured by fluorescence quantitative spectrophotometric method, and cell supernatants of tumor necrosis factor-α( TNF-α) release were detected by ELISA. Results After total saponins of Chaenomeles speciosa were co-cultured with RBL-2H3 mast cells with different antigen stimulation, β-hexosaminidase release rates and the levels of TNF-α of mast cells significantly decreased compared with the control group. Conclusion Total saponins of Chaenomeles speciosa inhibit the degranulation of RBL-2H3 mast cells in a dose dependent manner, which provids basis for studying mechanism of inhibiting allergic reactions.

Application of RBL-2H3 cells on allergenicity assessment of Qing kailing and Tanreqing Injections / 中草药

Objective: To explore the allergenicity of two kinds of Chinese materia medica (CMM) injections, Qingkailing (QKL) and Tanreqing (TRQ) Injections, with serum antibody sensitized RBL-2H3 cells. Methods: The antiserum was prepared by sc injection of allergen composed of ovalbumin (OVA), QKL, or TRQ combined with aluminum hydroxide adjuvant respectively in Wistar rats. The total IgE level in serum antibody was determined by radioimmunoassay. The RBL-2H3 cells were sensitized with serum antibodies, then stimulated by OVA, QKL, or TRQ after 48 h. The release rate of β-hexosaminidase in the supernatant was determined after the degranulation of sensitized RBL-2H3 cells. Passive cutaneous anaphylaxis (PCA) test was performed with rats, and the positive reaction rate with blue plaque in animal skin was observed. Results: Compared with the control group, the total IgE level in serum antibody was increased significantly in OVA, TRQ, and QKL groups (P < 0.05). The degranulation test revealed that the release rate of β-hexosaminidase was significantly increased in the supernatant when the cells were incubated with the antiserum and then stimulated with OVA, QKL, and TRQ. Compared with the control group, the largest relative times of release were 3.7, 1.53, and 1.98, respectively. The results of PCA test showed that the highest percentage rates of positive reaction of blue plaque were 100%, 100%, and 86% respectively. The results of RBL-2H3 cell test and PCA test have good consistency. Conclusion: The serum antibody sensitized RBL-2H3 cell model can be used for screening or assessing allergenicity of CMM injection.

Study of degranulation induced by the chemical composition of polysorbate 80 in a rat mast (RBL-2H3) cell line / 中国药学杂志

OBJECTIVE: To study directive effects of eight types of the chemical composition of polysorbate 80 on the degranulation in the RBL-2H3 rat mast cell line and to illuminate the material basis for its pseudoallergy. METHODS: RBL-2H3 cells were cultured and treated with varying dosage of eight types of the chemical composition of polysorbate 80. And then the amount of the released β-hexosaminidase was detected. MTT assay was used to determine the cytotoxicity of eight types of the chemical composition of polysorbate 80 which causing RBL-2H3 cells degranulation. RESULTS: PSM, PSD and PIM induced RBL-2H3 cells' degranulation in a concentration-dependent manner. Degranulation was not detected in cells treated with PS and PI. PSTri, PSTetra and PSD weakly induced the degranulation of RBL-2H3 cells in a concentration-dependent manner. PSM, PSD and PIM showed cytotoxicity with concentration-dependent manner, while PS and PI had no cytotoxicity. PSTri, PSTetra and PSD showed low toxicity cytotoxicity in a concentration-dependent manner. CONCLUSION: PIM is a major source of toxic substances polysorbate 80, the limit of which must be controlled.

"Influences of ""Antiphlogistic No.1"" on the degranultion of Activated RBL-2H3 cells" / 国际中医中药杂志

Objective To investigate the direct effect ofAntiphlogistic No.1 on the degranultion of RBL-2H3 mast cells stimulated by anti-DNP IgE and DNP-BSA complex.Methods The effect of Antiphlogistic No.1 on stabilization of RBL-2H3 cell membrane was assessed by degranultion inhibition rate.β-hexosaminidase and IL-4 released from RBL-2H3 cells were detected by PNAG colorimetric assay and ELISA.Results β-hexosaminidase and cytokine IL-4 production releases from RBL-2H3 cells was reduced after they had been treated with Antiphlogistic No.1.The inhibition rate of β-hexosaminidase release was 42.47％ at the concentration of 8 μg/ml (P＜0.01) and dose dependently increased to 52.40％,68.26％ and 72.15％ respectively when drug concentration up to 80 μg/ml,800 μg/ml,8000 μg/ml,while inhibition rate of IL-4 generation were 13.87％,23.27％,31.95％,39.99％ (P＜0.01).Antiphlogistic No.1 maximum inhibition rate of β-hexosaminidase release is 84.48％ of dexamethason maximum inhibition rate while Antiphlogistic No.l maximum inhibition rate of IL-4 is close to dexamethason maximum inhibition rate.Conclusion Antiphlogistic No.1 could stabilize the cellular membrane of RBL-2H3 and provide protection against Ⅰ type allergic response.