口服酵母菌對BALB/c小鼠鼻腔黏膜免疫之調節能力

Abstract

來自靈芝、酵母菌等真菌細胞壁的多醣類，如以β(1→3), β(1→6)鍵結之化合醣類，統稱為β-聚糖。β-聚糖被報導具有免疫調節的能力，如增進免疫力能預防癌症及微生物感染；或是改變免疫反應的途徑，如降低Th2反應卻增加Th1反應，以減少過敏發生。而鼻腔內給予之疫苗能除了引發接種者血清中特異性免疫球蛋白G (Immunoglobulin G, IgG)，更能使接種者產生在上呼吸道局部的分泌型免疫球蛋白A，IgA在黏膜能中和外來物抗原，降低經飛沬傳染散播的微生物入侵宿主之機率，這是注射疫苗很難達到的效果。並且鼻腔疫苗有容易施行大規模接種之優點，雖然大部分鼻腔疫苗尚在實驗階段，但其具有研發潛力。實驗建立鼻腔內致免的動物模式。以大腸桿菌致病株所分離的忌熱性腸毒素(heat-labile enterotoxin, LT)做為佐劑，卵清白蛋白(ovalbumin, OVA)為抗原，從鼻腔給予BALB/c小鼠。而小鼠從致免前一周開始每周三次分別餵食二次水、熱致死之啤酒酵母或市售啤酒酵母大豆發酵產物直到犧牲。實驗期間，每週採集小鼠的唾液、測定抗白蛋白之分泌型IgA以及採集血清測定抗OVA之IgG和IgE。結果顯示，小鼠餵食啤酒酵母及市售啤酒酵母大豆發酵產物的小鼠唾液中有較高的抗OVA特異性唾液IgA及血清中IgG和IgE。初步認為飲食中含有啤酒酵母及市售啤酒酵母大豆發酵產物可促進特定免疫球蛋白生成，可能透過Th1之細胞激素IFN-γ和Th2之細胞激素IL-5的分泌增加。因此服用熱致死啤酒酵母的相關產品可能加強宿主保護力，增進鼻腔內疫苗效果，但亦有增加對特定抗原過敏之風險。

β-glucans as β(1→3), β(1→6) binding polysaccharides derived from fungal cell wall, like Ganoderma lucidum and yeasts. β-glucans have been reported that confers immunomodulation with oral administration or intravenous injection. The immunomodulated functions of β-glucans may promote lymphocytes tumor cytotoxic ability or protect against microbial infections. Nevertheless, some kinds of β-glucan can also skew Th1/Th2 balance, may inhibit allergic response. Intranasal administrated nasal vaccines elicit hosts’ systemic specific immunoglobulin G (IgG), also elicit scretory IgA that may neutralize respiratory pathogens at local mucosa. Nasal vaccines are potential, since they are easily accessible for large population, and required without needles and syringes. In present research, we nasal immunized BALB/c mice with heat-labile enterotoxin(LT) from wild-type entero-pathogenic E. coli and ovalbumin (OVA) for 4 times, 1-week internal. In parallel, we oral administrated the mice with sterile water, heat-killed sacchromyces cerevisiae, or commercial sacchromyces cerevisiae legume fermentated product trice a week, started from 1 week before the first nasal immunization, and last to the second week after the last immunization, mice were sacrificed. Saliva, serum of mice was collected every week since feeding started, the samples were detected the specific anti-OVA IgA, IgG and IgE with ELISA. The present data shows that anti-OVA salivary IgA and anti-OVA serum IgG1, IgG2a and IgE in sacchromyces cerevisiae and commercial sacchromyces cerevisiae legume fermentated product-feeding mice with LT+OVA immunized. It’s preliminarily considered that sacchromyces cerevisiae or related products-intake may enhance specific antibody production, through IL-5 and IFN-γ-secreting increased. Therefore, oral intake sacchromyces cerevisiae or related products may protect hosts against pathogen, enhance nasal vaccine efficacy, but increase IgE-mediated allergy risk.