Characterization of a variant of carcinoembryonic antigen (CEA) using monoclonal and polyclonal anti-CEA antibodies

A variant of the carcinoembryonic antigen (CEA) with lower molecular weight than a CEA reference preparation has been separated from CEA. Using a polyclonal, spleen absorbed anti-CEA antiserum, the variant crossreacts with reference CEA in immunodiffusion. The CEA-activity of the variant has been demonstrated using an enzyme-immunoassay with monoclonal CEA specific antibodies. There is sufficient immunological evidence that this variant is a distinct antigen different from the crossreactive antigens described so far. The reactivity of the polyclonal anti-CEA antiserum with the CEA variant was abolished by absorption against the immobilized variant.     

抗呼吸道合胞病毒(RSV)单克隆抗体的制备及其对RSV病毒株抗原性的分析

用呼吸道合胞病毒R6(武汉地方株)活毒滴鼻加用戍二醛固定的病毒感染的Hela细胞免疫BALB/C鼠,取脾细胞与小鼠骨髓瘤SP_2/0细胞融合,培育出分泌抗呼吸道合胞病毒单克隆抗体的杂交瘤细胞13株,这些细胞的染色体数为94至104条,其分泌的抗体分别属于鼠IgC_1、IgG_(2a)、IgG_(2b)亚类。腹水荧光抗体滴度为1:10000～1:100000。其中五株单抗有中和病毒作用,尤其是两株中和放价达1:128。应用免疫转印法证实了这些单抗分别能识别RSV6种主要结构蛋白,用7株识别不同病毒结构蛋白的单抗对12株合胞病毒进行抗原性分析,可将这些病毒区分为二个血清型,即A亚型和B亚型。     

两株粗糙型沙门氏菌对小鼠抗异源G~-杆菌攻击的免疫保护研究

本文对引自日本的一株粗糙化学型变异株明尼苏达沙门氏菌Re595(J)和引自美国的一株Re595(A)对小鼠异源性G~-杆菌主动和被动保护作用进行了比较。结果表明,两株菌对异源G~-杆菌的大肠杆菌和变形杆菌攻击均有良好的保护作用,但Re595(J)对抗肺炎克雷伯氏杆菌攻击的保护作用明显优于Re595(A),而Re595(A)抗绿脓杆菌攻击的保护作用则明显优于Ke595(J)。表明两株Re595的免疫原存在着差异。     

Expression of a gene encoding a rabbit sperm membrane protein in mammalian cells.

A general mammalian expression vector designated pSV2-EP was reconstructed by inserting an oligonucleotide fragment into pSV2-dhfr. This vector allowed insertion of cDNAs with EcoRI cohesive ends. The pSV2-EP contains a simian virus 40 (SV40) early promoter, origin for DNA replication, SV40 poly-A site, splicing site, an initiator ATG downstream from the promoter and an EcoRI site for the insertion of cDNA fragment screened from lambda gt11 expression libraries. A recombinant plasmid (pS-VRS-1) was constructed by inserting RSD-1, a cDNA encoding a rabbit sperm tail protein, into the EcoRI site of the pSV2-EP vector. Chinese hamster ovarian (CHO) dhfr-negative cells were cotransformed with pSV2-dhfr and pSVRS-1 by the calcium phosphate method. In selective culture medium without thymidine and hypoxanthine, several cell lines were obtained containing mRNA and DNA that hybridized with RSD-1. One of these transformed cell lines stained intensely with anti-rSMP-B antibodies, demonstrating that the RSD-1 was expressed in the transformed CHO cells.     

一株广谱中和抗原性出血热病毒株的发现

一株分离自杭州市褐家鼠的出血热病毒Gou_3株的免疫血清对10株I型病毒的中和滴度除二株为160外均为320,而对4株Ⅱ型病毒的滴度为320—640,说明Gou_3株免疫血清对两型毒株中和效价大多数无差异或只差2倍,是一株中和抗原广谱的毒株。用I型和Ⅱ型毒株免疫血清对Gou_3株进行型别检定结果表明Gou_3株是Ⅱ型病毒。     

Altered reactivity of immunoglobulin produced by human-human hybridoma cells transfected by pSV2-neo gene

The HB4C5 and HF10B4 cell lines are human-human hybridomas producing human IgM monoclonal antibodies (MAbs) reactive to porcine carboxypeptidase A (CPase), but not to double stranded DNA (ds DNA). We obtained G418-resistant HB4C5 and HF10B4 cells by an introduction of pSV2-neo DNA. Almost all of the G418-resistant clones produced MAbs reactive to not only the CPase but the ds DNA. The results of the inhibition ELISA suggested that the cross-reactivity of the antibodies from G418-resistant clones to CPase and ds DNA was responsible for the alteration on their antigen specificity. HB4C5 and HF10B4 cells and their G418-resistant clones produced antibodies having glycosylated chain. The antibodies produced by tunicamycin-treated G418-resistant subclones of HB4C5 and HF10B4 lost the ability to bind to ds DNA, but retained the ability to bind to CPase. These results suggest that an introduction of pSV2-neo DNA into these hybridomas alters the specificities of their MAbs, and that the alteration to antigen binding specificities of their MAbs may be associated with glycosylation of the MAbs by these hybridomas.     

Some factors influencing the proportion of periplasmic hepatitisB virus pre-S2 antigen in the recombinant yeastHansenula polymorpha

Summary A central composite design (CCD) was used to evaluate, for the purpose of future process optimization, the influence of pH, yeast extract and ammonium chloride concentrations on the proportion of periplasmic hepatitisB pre-S2 antigen in the recombinant yeastHansenula polymorpha. Each factor was tested at five levels, and a second order polynomial model for the proportion of periplasmic antigen was fitted to the treatment combinations. pH showed the greatest effect: the proportion of periplasmic antigen was greatly increased at the higher pH levels. At the higher pH levels used, the proportion of periplasmic antigen was enhanced by a high concentration of ammonium chloride. Additional experiments have confirmed both the validity of the selected model and the optimal conditions found. A significant correlation was found between the proportion of periplasmic antigen and the total yield of antigen. These results indicated that is should be possible to modulate the distribution of the pre-S2 antigen between the periplasm and the cytoplasm of the yeast.     

~(125)Ⅰ标记单抗LC-I与肺腺癌细胞体内外结合特性的研究

本文用~(125)Ⅰ标记LC-1进行了一些体内外实验。实验结果表明:LC-1单抗的结合常数为4.8×10~8M~(-1),LC-1针对的SPC-A_1细胞表面抗原的位点数为7.2×10~4/细胞;LC-1与LAC-122两单抗针对的抗原决定簇没有交叉;用蛋白酶和过碘酸钠处理SPC-A_1细胞,前者对LC-1的结合抑制39%,后者抑制66%;LC- 1不但有较强的体外结合靶细胞的能力,从LC-1在荷瘤裸鼠中的组织器官分布来看,LC-1与肿瘤有较高的体内亲和性,并且是特异性的结合。