REGULATION OF IGA PRODUCTION AND TRANSPORT BY VITAMIN A

最近的流行病学研究表明，边缘儿童 维生素A缺乏症(VAD)发展和死亡的风险增加 呼吸道和肠道感染。分泌型IgA系统发挥作用 在预防此类感染方面发挥重要作用。VAD可能 通过减少分泌物增加对粘膜感染的敏感性 免疫球蛋白或损害其跨上皮细胞表面的运输。这样的缺陷 与维生素A在人体内的作用一致 刺激和维持黏膜上皮细胞的分化 细胞及其最近发现的在调节抗体中的作用 制作。出于这些原因，我们建议研究一下 维生素A对BALB/c小鼠分泌型IgA反应的影响具体目标1 将确定VAD是否影响粘膜IgA反应和血清免疫球蛋白 对鼻腔感染甲型流感病毒或鼻腔感染的反应 用灭活病毒免疫。下面的实验将是 进行：(A)总和甲型流感特异性免疫球蛋白A的浓度 用酶联免疫吸附试验检测唾液、鼻咽液中的免疫球蛋白 分泌物，(Iii)气管和支气管肺分泌物和(Iv)血清 VAD小鼠和对照组小鼠。(B)产生浆细胞的数目 针对甲型流感的免疫球蛋白和免疫球蛋白将由ELISPOT在 VAD小鼠和对照组小鼠的呼吸道和脾组织。(C) 预防二次感染的VAD将通过测量确定 病毒在上呼吸道和下呼吸道的复制(通过空斑分析) 先前感染或免疫的VAD和对照小鼠的区域。特定的 目标2将确定聚合免疫球蛋白A(PIgA)是否通过 聚合物免疫球蛋白受体(PIgR)受维生素A状态的影响。 将进行以下实验：(A)肝细胞介导 静脉注射PIGA进入胆汁的运输将是 在VAD和对照组小鼠中进行测量。(B)肝细胞pIgR蛋白水平将 免疫印迹法检测VAD与VAD的比较 控制小鼠。(C)组织信使核糖核酸水平和转录速率 PIgR基因将用单抗进行检测 溶液杂交(MASH)试验和核径流试验， 分别在VAD小鼠和对照组小鼠中进行。

Recent epidemiologic studies have shown that children with marginal vitamin A deficiency (VAD) are at increased risk of developing and dying from respiratory and enteric infections. The secretory IgA system plays an important role in protecting against such infections. VAD may increase susceptibility to mucosal infections by decreasing production of IgA or impairing its transport across epithelial surfaces. Such defects would be consistent both with vitamin A's well-characterized role in stimulating and maintaining the differentiation of mucosal epithelial cells and with its more recently identified role in regulating antibody production. For these reasons we propose to examine the effect of vitamin A on the secretory IgA response in BALB/c mice. Specific Aim 1 will determine if VAD affects the mucosal IgA response and serum IgG response to intranasal infection with influenza A virus or intranasal immunization with inactivated virus. The following experiments will be conducted: (A) The concentration of total and influenza A-specific IgA and IgG will be measured by ELISA in the (i) saliva, (ii) nasopharyngeal secretions, (iii) tracheal and bronchopulmonary secretions and (iv) serum of VAD and control mice. (B) The number of plasma cells producing influenza A-specific IgA and IgG will be enumerated by ELISPOT in the respiratory tract and spleen of VAD and control mice. (C) The effect of VAD on protection against reinfection will be determined by measuring virus replication (by plaque assay) in the upper and lower respiratory tract of previously infected or immunized VAD and control mice. Specific Aim 2 will determine if the transport of polymeric IgA (pIgA) via the polymeric immunoglobulin receptor (pIgR) is affected by vitamin A status. The following experiments will be conducted: (A) Hepatocyte-mediated transport of intravenously administered pIgA into the bile will be measured in VAD and control mice. (B) Hepatocyte pIgR protein levels will be measured by western immunoblot analysis and compared between VAD and control mice. (C) Tissue mRNA levels and the rate of transcription of the pIgR gene will be measured using the monoclonal-antibody solution-hybridization (MASH) assay and nuclear run-off assays, respectively, in VAD and control mice.