胃酸成膠性褐藻酸包覆口服銀耳多醣修飾之微脂粒 H5N3 死毒疫苗對小 鼠免疫力之評估
本實驗中，我們評估一種新的口服疫苗輸送系統：胃酸成膠性褐藻膠包覆銀耳多醣修飾 微脂粒；結合褐藻膠之高分子聚合物 ( 抵抗胃酸破壞 ) 、微脂粒 ( 疫苗佐劑 ) 輸送系統 和銀耳多醣 ( 免疫刺激 ) 特性。我們利用 95 % PC 之多層球微脂粒包覆 106.0 EID50/mL H5N3(LV 組 ) 死毒再用銀耳多醣 (TFP) 修飾微脂粒表面 24 小時 (LTV 組 ) 。單純 H5N3 病毒 (V 組 ) 、 LV 、 LTV 組分別與含有磷酸三鈣之 1.5 % alginate 混合 (AV 、 ALV、 ALTV 組 ) 。
將疫苗與胃酸成膠性褐藻酸混合，並進行體外溶離試驗，當胃酸成膠性褐藻酸與模 擬胃液接觸時就會形成褐藻膠將微脂粒疫苗包覆起來，而保護微脂粒疫苗不受胃酸破壞，並且在進入腸道時可以調節釋放微脂粒疫苗。而經由單層 Caco-2 細胞的跨細胞上皮 電阻值 ( TEER ) 實驗顯示，在腸道釋放後之微脂粒疫苗， LV 和 LTV 組都能夠打開 C aco-2 細胞單層膜間的緊密聯合 ( 分別是 77.4% 與 75.4% 比率，兩組沒有顯著差異 ) 。 而在 TEER 的恢復實驗中，可以觀察到 LV 與 LTV 組給予 Caco-2 之後，再給予細胞培 養後細胞間緊密聯合可以恢復，細胞也能存活。
動物實驗顯示褐藻膠包覆之疫苗在第二次免疫後 3 週可以誘發腸道 sIgA 的產生，雖然 在血清中 IgG 沒有預期中的提高，且血球凝集抑制實驗也顯示沒有足夠的抗體保護效 力。但是有可能是因為行 Th1 免疫途徑而抑制了體液性免疫反應。
經由以上的結果顯示，胃酸成膠性銀耳多醣修飾之微脂粒口服疫苗對於提高腸黏膜 IgA 有一定的能力，而這樣型式的一種疫苗載體再經過材料上的改進，期盼其具有攜帶 不易經由口服吸收的疫苗載體的潛力。Assessment of TFP-modified liposomal oral H5N3 inactive vaccine entr apped in HCl-induced alginate gel for mice immunity
In this study, we evaluate a novel delivery system for oral vaccines, TFP-modified liposomes entrapped in acid-induced alginate (ALT) of biodegradable polymers, which is conceived from a combination of the pol ymer, the lipid–based delivery system and immunostimulant. We utilized liposomes (multilamellar, MLV) of 95 % PC to encapsulate 106.0 EID50/mL inactive H5N3 virus (LV group) and coated with Tremella fuc iformis polysaccharide (TFP), purified from hot water extracts of Tremella fuciformis, for 24 hr (LTV grou p). The virus(V), LV, LTV mixed within 1.5 % alginate with tricalcium phosphate, respectively (AV, ALV and ALTV group).
The vaccine mixed with acid-induced alginate used for in vitro release study. When HCl-induced alginate c ontact with HCl to forming alginate gel that was more resistant in acidic pH and modulated the release prof iles of the encapsulated vaccines in the alkaline pH. Transepithelial electrical resistance (TEER) studies rev ealed that LV and LTV were able to opening the tight junctions (about 77.4 % and 75.4 % of the initial val ue, respectively) of Caco-2 cell monolayer by about three times. Recovery studies on the TEER showed tha t the effect of the LV and LTV vaccines on Caco-2 cell monolayer is reversible and proves the viability of cells after incubation with all vaccines.
The animal exp. showed that vaccine entrapped in alginate gel induced intestinal sIgA production at 3wk a fter second administration. although IgG in serum not expected to increase, and the hemagglutination inhib ition test also showed that there was insufficient protection of the effectiveness of the antibody. However, t here may be because it means Th1 immune suppression of the humoral immune response.
