Dose and Load Studies for Subcutaneous and Oral Delivery of Poly(lactide-co-glycolide) Microspheres Containing Ovalbumin

Poly(lactide-co-glycolide) microspheres containing different loads of OVA (0.05, 0.1, 0.5 and 1.0% w/w) were manufactured by a w/o/w emulsion/solvent evaporation method. Low load efficiencies of less than 20% were observed. Normal size distributions with mean volume diameters ranging from 3.7 to 4.7 µm were obtained for different batches. The in vitro release of OVA from different loaded microspheres showed an expected burst release with all batches. The in vivo dose study (1, 10, 25, 50 µg of OVA) was performed by subcutaneous and oral inoculation in mice by single (0 week) or double (0 and 3 weeks) administration of PLGA 50/50 microspheres containing 0.1% OVA. Subcutaneous administration showed an immune response (serum Ig levels by ELISA) statistically (Fishers paired t-test; P < 0.05) above OVA saline negative controls at 3, 6 and 12 weeks after administration. Oral administration of microspheres produced statistically higher systemic immune responses at the higher doses. Single and double inoculation orally and subcutaneously produced similar serum antibody levels. The in vivo load study was performed by subcutaneous and oral administration to mice of 25 µg OVA contained in various loaded (0.05, 0.1, 0.5 and 1.0% w/w) microspheres. Serum immune responses at 3, 6, and 12 weeks after inoculation were statistically above OVA saline controls and were inversely proportional to the OVA load using either route. This observation suggested a relationship between the number of microspheres delivered and the in vivo serum response. Single subcutaneous administration of 0.05 or 0.1% OVA loaded PLGA 50/50 microspheres induced larger immune responses compared with complete Freunds adjuvant.     

干扰素防治狂犬病毒感染的小鼠实验

用小鼠试验干扰素防治狂犬病毒 (CVS)感染的作用 ,结果表明 ,小鼠在感染CVS前 2周开始使用干扰素 ,可获得 5 0 %左右的保护率 ,而在感染CVS后使用干扰素却无保护作用。干扰素与狂犬病疫苗联合使用可获得比两者单独使用更佳的保护效果 ,疫苗效力可提高 5倍以上。 5× 10 3IU剂量组与 5× 10 2 IU剂量组干扰素作用无显著差异。     

血源乙型肝炎疫苗免疫持久性观察

为了解血源乙型肝炎（乙肝）疫苗的免疫持久性,对澄江县1991～1995年按照0、1、6个月免疫程序完成血源乙肝疫苗接种的人群,按接种后间隔1～5年分组,每组随机抽取100名儿童,采末梢血,共得517份免疫者的血清样品．用酶联免疫吸附试验（ELISA）检测抗-HBs、HBsAg。结果表明,接种乙肝疫苗2年内抗-HBs阳性率在90％以上,以后随间隔年眼的延长而明显下降,间隔5年降至60％,人群平均保护率达78.57％．     

甲型肝炎疫苗免疫前后发病情况分析

为比较沙县在甲型肝炎（甲肝）疫苗免疫前后甲肝的发病情况,对本站疫情定收集的1990～1997年报告的882例甲肝病例进行了分析。结果表明,疫苗免疫前甲肝发病率在63.36／10万～99.90／10万,免疫后为16.20／10万～21.87／10万,免疫前后平均发病率之比为422：1。按＜15岁、15～44岁和≥45岁分组,发病率下降最明显的是＜15岁,其次是15～44岁和≥45岁,依次下降了91.9％、70.1％和37.1％．工人、农民、学生（大、小、小学生）不同职业人群,以学生下降最明显,农民下降不明显,存在差别的原因可能是甲肝疫苗接种率的高低。甲肝疫苗接种的成本效益为1：953．     

流行性乙型脑炎减毒活疫苗免疫学效果观察

1998年5月,我们在江苏省新沂市选择1～1．5岁健康儿童进行流行性乙型脑炎（乙脑）减毒活疫苗免疫学效果观察．免疫前和免疫后1个月各采血检测乙脑反向被动血凝（RPHI）抗体．检测到合格双份血清87人,抗体测定免疫前阴性44人．其免疫后抗体阳转率为93．18％,免疫前阳性43人,其免疫后抗体≥4倍增长率为34．88％,表明乙脑减毒活疫苗的免疫成功率是较高的．     

The construction ofSchistosoma Japonicum vaccine BCG-Sj26GST and its identification

Summary The expression of foreign gene,Schistosoma Japonicum 26 ku antigen (Sj26GST),in Bacillus Calmette-Guerin (BCG),Mycobacterium CM. smegmatis) andEscherichia coli (E. coli) were studied. The cDNA fragment encoding Sj26GST was amplified by PCR using plasmid pGEX, which could express Sj26GST inE. coli as template. The Sj26GST cDNA was cloned into the downstream of humanM. tuberculosis heat shock protein (hsp) 70 promoter with correct reading frame, and then the DNA fragment containing hsp70 promoter and Sj26GST gene were subcloned together intoE. coli-Mycobacteria shuttle plasmid pBCG-2000 to construct the expression shuttle plasmid pBCG-Sj26. The recombinant BCG andM. smegmatis mc²155, which were electroplated with pBCG-Sj26, could express Sj26GST and the recombinantSchistosoma Japonicum vaccine BCG-Sj26GST was made. The recombinant Sj26GST (rSj26GST) were soluble and could be observed on SDS-PAGE at molecular weight of 26 ku. The content of rSj26GST accounted for 15% and 10% of total bacterial protein in BCG andM. smegmatis respectively. The results of Western blot showed the combination of rSj26GST with antibody of GST. This project was supported by Primary Foundation of China (No. 94-Y-19), Chinese National Nature Science Foundation (No. 339480022) and Chinese Health Foundation (No. 94-1-131).     

两种产地的乳蛋白对狂犬病疫苗毒力的影响

目的　提高狂犬病疫苗的病毒滴度,以降低浓缩倍数,减缓临床反应。方法　采用含有不同产地水解乳蛋白和氨基酸的平衡盐溶液,培养原代地鼠肾细胞,种毒,收获病毒液,测定其病毒滴度。结果　二种培养液收获的病毒液其病毒滴度差异明显（ Ｐ＜ ００１） 。结论　用美国产水解乳蛋白培养的细胞贴壁均匀且快。     

重组日本血吸虫SjGST-Sj32蛋白诱导小鼠保护性免疫的研究

应用基因工程技术分别表达出ＳｊＧＳＴＳｊ３２,Ｓｊ３２和ＳｊＧＳＴ,用于保护性免疫的动物实验及其体液免疫机制的初步探讨。结果：与对照组相比,重组ＳｊＧＳＴＳｊ３２组,Ｓｊ３２组,Ｓｊ３２＋ＳｊＧＳＴ组均有明显的减虫效果（Ｐ＜０．０５）。上述三组及ＳｊＧＳＴ组的肝脏虫卵计数均较对照组为少（Ｐ＜０．０１）。提示重组Ｓｊ３２ｋＤ蛋白可诱导小鼠产生明显的抗日本血吸虫攻击感染的保护性免疫及抗生殖免疫效果,而ＳｊＧＳＴ仅表现出一定的抗生殖免疫效果。