乳酸菌對免疫調節活性之機能性評估

Evaluation of Function of Immunomodulatory Activity for Lactic Acid Bacteria

邱文瑩

指導教授 ： 謝寶全 ； 陳武元

國立屏東科技大學/農學院/食品科學系所/碩士(2008年)

摘要

過敏性疾病顯示出在高度工業化的國家中有穩定增加的現象。根據文獻指出，減少微生物的刺激將會促使過敏性疾病的增加。然而，若是於童年時期藉由益生菌改變腸道菌群的組成，則有利於過敏疾病的減緩。益生菌像是乳酸菌存在於發酵食品中屬於正常腸道菌群，對於人類健康具有益的功效。因此，本研究收集市售商品及自然界樣品分離出生長快速之乳酸菌，測試評估其益生菌特性，並且以體外及體內試驗評估乳酸菌之免疫調控活性。在體外試驗結果顯示有21株乳酸菌具備有益生菌之基本特性，如對pH 3具有耐受性、生長於0.3%膽鹽中及可吸附於腸道細胞。由以上試驗結果，挑選出5株乳酸菌(B-121、123、 145、183 及184)，進一步與人類週邊血液單核細胞進行培養，結果顯示5株乳酸菌具有抑制PHA刺激之週邊血液單核細胞(PBMCs)增殖能力，不同菌株具有減少Th2 細胞激素(IL-4及IL-6)之分泌，以及增加IFN-γ、TNF-α及IL-10的產生。並且減少IL-4/IFN-γ之比值，而B-121可以顯著增加IFN-γ和IL-10及減少IL-4產生，基於這些結果，本研究挑選出B-121菌株進行毒性評估。結果顯示，B-121菌株不會侵入腸道上皮細胞株Caco-2，且有增加初代小鼠肝細胞株(BNL CL.2)之存活率及抑制人類肝癌細胞株(Hep G2)之增殖。在體內試驗則使用以卵白蛋白誘發之小鼠氣喘模式，在抗原刺激前餵食B-121菌株，發現經B-121菌株處理之後，可以減緩細胞浸潤至氣管及肺部組織中，且降低Th2細胞激素產生及氣管過度反應之現象。綜合以上結果，推測乳酸菌B-121有免疫調節之機能性功效。

關鍵字

乳酸菌 ； 過敏 ； 細胞激素 ； 免疫調節

並列摘要

Atopic disease is showing a steadily increasing prevalence in highly industrialized countries. Recent reports have indicated that decreased exposure to microbial stimuli has been proposed to be involved in the increased prevalence of atopic disease. However, modification of the intestinal flora early in life by administration of probiotic bacteria may be a potential approach to prevent atopic disease. Probiotic bacteria as lactic acid bacteria (LAB) present in fermented foods or belonging to the natural intestinal microflora were shown to exert beneficial effects on human health. Therefore, Isolated strains of LAB from commercial products and natural sources were assessed for probiotic properties such as bile resistance, acid tolerance, and adhesion to intestinal mucous in this study. The immunomodulatory activity of LAB evaluated in vitro and in vivo. In vitro results showed that there were 21 strains the basic requirements for probiotic functions as they demonstrated probiotic characteristics such as tolerance to pH 3, growth in 0.3% oxgall and adhesion to intestinal cell. The studyselected 5 LAB strains (B-121, 123, 145, 183 and 184) that were tested with allergic peripheral blood mononuclear cell (PBMCs). The results showed that 5 LAB inhibited PHA-stimulated PBMCs proliferation. Different strains decreased the secretion of Th2 cytokines (IL-4 and IL-6) and increased high levels of IFN-γ, TNF-α, and IL-10. IL-10 production resulted in partial to suppression of Th2 cytokines production and concurred with an increase in pro-inflammatory cytokines as IFN-γ and TNF-α. And LAB reduced the secretion ratio of IL-4/IFN-γ by PBMCs from allergic patients. And B-121 strain showed a significantly increase expression of IFN-γ and IL-10 and decreased production of the cytokine IL-4. Based on these results, we selected B-121 strain that were tested for toxicity evaluation. The results showed that B-121 strain weren’t invasive to human intestinal epithelial cell line Caco-2, increased cell survival rate to BNL CL.2 and suppressed cell proliferation to Hep G2 in vitro. In vivo, the study used an ovalbumin-sensitized asthma model in BALB/c mice. Animals were treated with B-121 strain before antigen challenge. Oral treatment with B-121 strain attenuated the influx of cells to the airway lumen and parenchyma and reduced the levels of Th2 cytokine production in antigen-challenged animals, and also decreased allergen-induced airway hyperresponsiveness. Overall, the results suggest that there are function of immunomodulatory activity for B-121strain.

並列關鍵字

lactic acid bacteria, ； allergy ； cytokines ； immunomodulatory

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