Smith D J, Lam A, Barnes L A, King W F, Peacock Z, Wise D L, Trantolo D J, Taubman M A
Department of Immunology, The Forsyth Institute, Boston, MA 02115, USA.
Oral Microbiol Immunol. 2003 Aug;18(4):240-8. doi: 10.1034/j.1399-302x.2003.00074.x.
Intranasally administered dental caries vaccines show significant promise for human application. Alternate mucosal routes may be required, however, to induce caries-protective salivary IgA antibody in children with respiratory diseases. Since rectal mucosa contains inductive lymphoid tissue, we hypothesized that the rectal route could be used to induce salivary immunity to mutans streptococcal glucosyltransferase (GTF), resulting in protective immunity to experimental dental caries. We first explored the ability of glucosyltransferase, incorporated into polylactide-co-glycolide (PLGA) microparticles (MP), and administered rectally together with mucosal adjuvant, to induce a salivary IgA antibody response. Groups of Sprague-Dawley rats (6/group) were immunized rectally on days 0, 7, 14 and 21 with a) GTF-MP alone, b) GTF-MP with cholera toxin, c) GTF-MP with detoxified mutant Escherichia coli toxin (dLT), or d) sham immunized with PLGA and cholera toxin. An additional group was immunized intranasally with GTF-MP alone. Saliva and nasal washes of all intranasally immunized rats contained IgA antibody to glucosyltransferase on day 28. Salivary IgA antibody was also detected in 7/12 rats rectally immunized with GTF-MP and cholera toxin or dLT, although responses were lower than those obtained by intranasal immunization. Most fecal extracts from rectally delivered GTF-MP plus cholera toxin or dLT rats contained IgA antibody to GTF-MP. Low levels of fecal IgA antibody were detected in 3/6 intranasally immunized rats and 2/6 rats rectally immunized with GTF-MP alone. We then examined the extent to which salivary IgA antibody induced by the rectal route could be protective. At 25, 31 and 38 days of age, two groups of female Sprague-Dawley rats (13/group) were rectally immunized with GTF-MP and cholera toxin or with empty microparticles and cholera toxin (sham group). A third group was intranasally immunized with GTF-MP alone. After demonstrating salivary IgA responses to GTF in most GTF-immunized rats, all animals were infected with streptomycin-resistant Streptococcus sobrinus and placed on diet 2000. After 79 days of infection, total caries on molar surfaces were lower in both rectally (7.9 +/- 1.0) and intranasally (7.1 +/- 0.9; P < 0.0.03) immunized groups compared with the sham-immunized group (11.9 +/- 1.6). Smooth surface caries were significantly lower (P < 0.05) in both rectally and intranasally immunized groups. These results support the interconnectedness of the mucosal immune system and indicate that rectal immunization with GTF-MP, together with adjuvant, or intranasal immunization with GTF-MP alone, can induce protective levels of salivary antibody in rats.
经鼻给药的龋齿疫苗在人类应用方面显示出巨大潜力。然而，对于患有呼吸道疾病的儿童，可能需要采用其他黏膜途径来诱导具有龋齿保护作用的唾液IgA抗体。由于直肠黏膜含有诱导性淋巴组织，我们推测直肠途径可用于诱导针对变形链球菌葡糖基转移酶（GTF）的唾液免疫，从而产生针对实验性龋齿的保护性免疫。我们首先探究了包载于聚乳酸-羟基乙酸共聚物（PLGA）微粒（MP）中的葡糖基转移酶与黏膜佐剂一起经直肠给药诱导唾液IgA抗体反应的能力。将Sprague-Dawley大鼠分成若干组（每组6只），于第0、7、14和第21天经直肠免疫：a）单独使用GTF-MP；b）GTF-MP与霍乱毒素联合使用；c）GTF-MP与解毒的突变大肠杆菌毒素（dLT）联合使用；d）用PLGA和霍乱毒素进行假免疫。另外一组经鼻单独免疫GTF-MP。在第28天，所有经鼻免疫大鼠的唾液和鼻腔灌洗液中均含有针对葡糖基转移酶的IgA抗体。在经直肠用GTF-MP和霍乱毒素或dLT免疫的12只大鼠中，有7只检测到唾液IgA抗体，尽管其反应低于经鼻免疫组。经直肠给予GTF-MP加霍乱毒素或dLT的大鼠，其大部分粪便提取物中含有针对GTF-MP的IgA抗体。在3/6只经鼻免疫的大鼠和2/6只单独经直肠用GTF-MP免疫的大鼠中检测到低水平的粪便IgA抗体。然后，我们研究了经直肠途径诱导的唾液IgA抗体的保护程度。在25、31和38日龄时，将两组雌性Sprague-Dawley大鼠（每组13只）经直肠用GTF-MP和霍乱毒素或用空微粒和霍乱毒素（假免疫组）进行免疫。第三组经鼻单独免疫GTF-MP。在证明大多数经GTF免疫的大鼠对GTF有唾液IgA反应后，所有动物均感染耐链霉素的远缘链球菌，并给予2000号饲料。感染79天后，与假免疫组（11.9±1.6）相比，经直肠免疫组（7.9±1.0）和经鼻免疫组（7.1±0.9；P<0.003）磨牙表面的总龋齿数均较低。经直肠和经鼻免疫组的光滑面龋齿均显著降低（P<0.05）。这些结果支持了黏膜免疫系统的相互联系，并表明用GTF-MP联合佐剂经直肠免疫或单独用GTF-MP经鼻免疫均可在大鼠中诱导产生具有保护作用水平的唾液抗体。
