Exacerbation of cigarette smoke-induced pulmonary inflammation by Staphylococcus aureus Enterotoxin B in mice

<p>Abstract</p> <p>Background</p> <p>Cigarette smoke (CS) is a major risk factor for the development of COPD. CS exposure is associated with an increased risk of bacterial colonization and respiratory tract infection, because of suppressed antibacterial activities of the immune system and delayed clearance of microbial agents from the lungs. Colonization with <it>Staphylococcus aureus </it>results in release of virulent enterotoxins, with superantigen activity which causes T cell activation.</p> <p>Objective</p> <p>To study the effect of <it>Staphylococcus aureus </it>enterotoxin B (SEB) on CS-induced inflammation, in a mouse model of COPD.</p> <p>Methods</p> <p>C57/Bl6 mice were exposed to CS or air for 4 weeks (5 cigarettes/exposure, 4x/day, 5 days/week). Endonasal SEB (10 μg/ml) or saline was concomitantly applied starting from week 3, on alternate days. 24 h after the last CS and SEB exposure, mice were sacrificed and bronchoalveolar lavage (BAL) fluid and lung tissue were collected.</p> <p>Results</p> <p>Combined exposure to CS and SEB resulted in a raised number of lymphocytes and neutrophils in BAL, as well as increased numbers of CD8⁺T lymphocytes and granulocytes in lung tissue, compared to sole CS or SEB exposure. Moreover, concomitant CS/SEB exposure induced both IL-13 mRNA expression in lungs and goblet cell hyperplasia in the airway wall. In addition, combined CS/SEB exposure stimulated the formation of dense, organized aggregates of B- and T- lymphocytes in lungs, as well as significant higher CXCL-13 (protein, mRNA) and CCL19 (mRNA) levels in lungs.</p> <p>Conclusions</p> <p>Combined CS and SEB exposure aggravates CS-induced inflammation in mice, suggesting that <it>Staphylococcus aureus </it>could influence the pathogenesis of COPD.</p

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Not AvailableHigher input costs involved in intensive farming of Litopenaeus vannamei drive back the small and marginal farmers from venturing into shrimp farming. The production potential and performance of the species was evaluated in low stocking short term farming in earthen pond conditions. Details from five crops with varying stocking densities, crop period and seasons were analysed to evaluate performance of the species. At higher stocking rates the shrimp yielded better production. The present report indicates better performance of the species in summer season. Interestingly all the observations point towards the fact that final harvest size depends on stocking density (SD), as well as days of culture (DOC) and it was observed that the minimum DOC to get a size of 20 g is around 80 days at SDs below 30 m-2. The economic returns increased with increase in SD and DOC. Overall results imply that at any given SD, the economic returns per kg will be minimal till 80 DOC (approximately 20 g harvestable size) at stocking density less than 30 m-2. The study confirms that for small and marginal farmers, L. vannamei farming can be made profitable at a shorter culture period (up to 80 days) adopting lower affordable stocking rates.Not Availabl