We have established a hybridoma producing monoclonal antibody (MAb) against a linear epitope of glycoprotein (G protein) of the RC-HL strain of rabies virus. This MAbl5-13 showed almost the same neutralizing activity to all of five rabies fixed strains, including RC-HL, and reacted to the denatured G protein in western blot analysis. To characterize and map this linear epitope, an antigenic variant NR15-13 was selected from RC-HL strain in the presence of neutralizing MAbl5-13. The variant reacted with MAbl5-13 in an immunofluorescent antibody test but was not neutralized by the antibody and the antibody did not bind to the variant G protein in a Western blot analysis. The variant NR15-13 had an amino acid substitution at position 251 of the G protein, where tryptophan of the parental RC-HL strain was replaced by arginine. Site-directed mutagenesis analysis using the expression system in simian COS7 cells revealed that a single amino acid substitution at 251-tryptophan by arginine on the G protein of the parental RC-HL strain abolished the antigenicity of the epitope for MAbl5-13 in western blot analysis, and the replacement of 251-arginine by tryptophan recovered the activity. These results strongly suggest that tryptophan at position 251 on the G protein is essential for construction of the linear epitope against MAbl5-13.

广西一些养殖场频繁发生以母猪流产、死胎、木乃伊等为特征的流行性传染病，怀疑为猪繁殖与呼吸综合征病毒（PRRSV）所致。利用针对PRRSV的N基因的特异性引物P1和P2，通过RT_PCR技术对分别从广西贵港市（GXGG）和南宁市（GXNN）收集到的可疑病料进行检测，结果两份为阳性。合成针对M基因的引物M1和M2，分别扩增了GXGG和GXNN两株PRRSV的M基因，并进行克隆和测序，得到长582个核苷酸的目的基因片段。应用DNAStar序列分析软件对所测的两个广西毒株与国内外已发表的ATCCVR_2332、LV和CH_la毒株进行同源性比较。分析表明，GXGG与ATCCVR_2332、LV、CH_la的核苷酸同源性分别为9516%、6915%、9717%；GXNN与ATCCVR_2332、LV、CH_la的核酸同源性分别为9419%、6915%、9713%。对推定的氨基酸序列进行了比较，GXGG与ATCCVR_2332、LV、CH_la的氨基酸同源性分别为9717%、8015%、9717%；GXNN与ATCCVR_2332、LV、CH_la的氨基酸同源性分别为9813%、7919%、9711%。说明广西流行毒株与ATCCVR_2332和CH_la的同源性很高，而与LV毒株的同源性很低。从本研究构建的系统发育树分析，广西流行的PRRSV与ATCCVR_2332株的亲缘关系比较密切。

从广西南宁、百色、柳州市采集了犬脑组织268份，从南宁市、博白县捕获蝙蝠320只，以及从南宁市郊捕获野鼠65只。应用RT-PCR技术对犬脑、蝙蝠和野鼠脑组织进行狂犬病病毒检测，并将阳性材料进行小白鼠脑内接种试验。检测结果表明，犬脑的狂犬病病毒阳性率为1.12%，蝙蝠阳性率为0.94%，野鼠阳性率为3.1%。本调查证明了广西除犬之外，野鼠和蝙蝠等野生动物也携带有狂犬病病毒。

本试验利用杆状病毒载体成功地表达狂犬病病毒糖（G）蛋白。从转染重组了日本动物用狂犬病病毒疫苗株RCHL株G蛋白基因的转移载体和野生型杆状病毒DNA的Sf-9细胞中，分离出2个重组杆状病毒克隆。应用印渍法和荧光抗体法（IFA）从重组杆状病毒感染的Sf-9细胞检出了狂犬病毒G蛋白。Sf-9细胞表达的G蛋白与狂犬病毒RCHL株感染NA细胞的G蛋白的分子量一致。35个抗RCHL株G蛋白的单克隆抗体均与重组杆状病毒感染的Sf-9细胞反应，表明表达的G蛋白的抗原性没有发生变异。表达的G蛋白主要分布在Sf-9细胞的膜表面，形成类似环状的荧光，这种荧光与RCHL株感染的NA细胞的荧光相同。