O型口蹄疫病毒VP1蛋白单克隆抗体的制备与生物学特性鉴定

目的为了获得针对O型口蹄疫病毒的单克隆抗体,本研究采用差速离心、半饱和硫酸铵沉淀和蔗糖密度梯度离心法提纯O型口蹄疫病毒液,免疫BALB/c小鼠,取脾细胞和SP2/0细胞融合,经ELISA方法筛选和3次亚克隆后获得2株稳定分泌表达的杂交瘤细胞株2C8和5G10,腹水抗体效价分别达到1∶6 400和1∶25 600。经亚类鉴定确定两株单抗均为IgM型,Western-blot、间接ELISA和IFA确定这2株单克隆抗体分别针对O型口蹄疫病毒VP1蛋白不同表位,从而,为研究FMDV的生物学特性和建立快速诊断方法的建立奠定了基础。     

Identification of NP Protein-Specific B-Cell Epitopes for H9N2 Subtype of Avian Influenza Virus

Avian Influenza (AI) caused by the H9N2 subtype of the avian influenza virus (AIV) poses a serious threat to both the poultry industry and to public health safety. NP is one of the major structural proteins in influenza viruses. B-cell determinants located on NP proteins have attracted increasing attention. In this study, based on the NP sequence of the H9N2 (A/chicken/Shandong/LY1/2017) strain, the truncated NP gene (71 AA–243 AA) was cloned and prokaryotically expressed in a pET-28a (+) vector. BALB/c mice were immunized with a purified recombinant of an NP protein to prepare a monoclonal antibody against NP proteins. The prokaryotic expression of four overlapping fragments, NP-N-96, NP-C-103, NP-C-54 and NP-C-49, were used to recognize an antigenic epitope of the NP protein. The results show that, after cell fusion, one hybridoma cell clone secreted the antibody specific to the NP protein, following screening with ELISA and indirect immunofluorescence, which is named the 4F5 monoclonal antibody (mAb). Western blotting on the overlapping fragments showed that the ²³⁰FQTAAQRA²³⁷ motif was identified as the minimal motif recognized by 4F5mAb, which was represented as the linear B-cell epitope of the NP protein. Homology analysis of this epitope shows that it was highly conserved in 18 AIVs analyzed in this study, and the epitope prediction results indicate that the epitope may be located on the surface of the NP protein. These results provide a strong experimental basis for studying the function of the NP protein of the H9N2 AIV and also strong technical support for the development of a universal assay based on an anti-NP monoclonal antibody.     

Comparative Proteomic Analysis Reveals Mx1 Inhibits Senecavirus A Replication in PK-15 Cells by Interacting with the Capsid Proteins VP1, VP2 and VP3

As an emergent picornavirus pathogenic to pigs, Senecavirus A (SVA) can replicate in pig kidneys and proliferates well in porcine kidney epithelial PK-15 cells. Here, tandem mass tags (TMT) labeling coupled with liquid chromatography–tandem mass spectrometry (LC-MS/MS) was used to analyze the proteome dynamic changes in PK-15 cells during SVA infection. In total, 314, 697 and 426 upregulated differentially expressed proteins (DEPs) and 131, 263 and 342 downregulated DEPs were identified at 12, 24 and 36 hpi, respectively. After ensuring reliability of the proteomic data by quantitative PCR and Western blot testing of five randomly selected DEPs, Mx1, eIF4E, G6PD, TOP1 and PGAM1, all the DEPs were subjected to multiple bioinformatics analyses, including GO, COG, KEGG and STRING. The results reveal that the DEPs were mainly involved in host innate and adaptive immune responses in the early and middle stages of SVA infection, while the DEPs mainly participated in various metabolic processes in the late stage of infection. Finally, we demonstrated that Mx1 protein exerts antiviral activity against SVA by interacting with VP1 and VP2 proteins dependent on its GTPase, oligomerization and interaction activities, while Mx1 interacts with VP3 only depending on its oligomerization activity. Collectively, our study provides valuable clues for further investigation of SVA pathogenesis.     

Experimental Senecavirus A Infection of Bovine Cell Lines and Colostrum-Deprived Calves

Senecavirus A (SVA) is a causative agent for vesicular disease in swine, which is clinically indistinguishable from other vesicular diseases of swine including foot-and-mouth disease (FMD). Recently, it was reported that buffalo in Guangdong, China were experiencing clinical symptoms similar to FMD including mouth ulcers and lameness tested positive for SVA. The objective of this study was to determine the susceptibility of cattle (Bos taurus) to SVA infection. Initial in vitro work using the PrimeFlow assay demonstrated that bovine cell lines and peripheral blood mononuclear cells from cattle were susceptible to SVA infection. Subsequently, six colostrum-deprived Holstein calves were challenged with SVA intranasally. No vesicular lesions were observed after challenge. Serum, oral, nasal, and rectal swabs tested for SVA nucleic acid did not support significant viral replication and there was no evidence of seroconversion. Therefore, demonstrating cattle from this study were not susceptible to experimental SVA infection.     

Antigenic Properties of N Protein of Hantavirus

Hantavirus causes two important rodent-borne viral zoonoses, hemorrhagic fever with renal syndrome (HFRS) in Eurasia and hantavirus pulmonary syndrome (HPS) in North and South America. Twenty-four species that represent sero- and genotypes have been registered within the genus Hantavirus by the International Committee on Taxonomy of Viruses (ICTV). Among the viral proteins, nucleocapsid (N) protein possesses an immunodominant antigen. The antigenicitiy of N protein is conserved compared with that of envelope glycoproteins. Therefore, N protein has been used for serological diagnoses and seroepidemiological studies. An understanding of the antigenic properties of N protein is important for the interpretation of results from serological tests using N antigen. N protein consists of about 430 amino acids and possesses various epitopes. The N-terminal quarter of N protein bears linear and immunodominant epitopes. However, a serotype-specific and multimerization-dependent antigenic site was found in the C-terminal half of N protein. In this paper, the structure, function, and antigenicity of N protein are reviewed.     

Development of Monoclonal Antibodies for Detection of Conserved and Variable Epitopes of Large Protein of Rabies Virus

Rabies virus (RABV) causes fatal neurological encephalitis and results in approximately 6000 human death cases worldwide every year. The large (L) protein of RABV, possessing conserved domains, is considered as the target for detection. In this study, three monoclonal antibodies (mAbs), designated as 3F3, 3A6 and L-C, against L protein were generated by using the recombinant truncated L protein (aa 1431–1754) and the epitopes were also identified using a series of overlapping truncated polypeptides for testing the reactivity of mAbs with different RABV strains. The ¹⁴⁷⁹EIFSIP¹⁴⁸⁴, ¹⁶⁵⁹RALSK¹⁶⁶³ and ¹⁷²⁴VFNSL¹⁷²⁸ were identified as the minimal linear epitopes recognized by mAbs 3F3, 3A6 and L-C, respectively. Amino acid alignment showed epitope ¹⁷²⁴VFNSL¹⁷²⁸ recognized by mAb L-C is completely conserved among RABV strains, indicating that mAb L-C could be used to detect all of the RABV strains. Epitope ¹⁴⁷⁹EIFSIP¹⁴⁸⁴ is highly conserved among RABV strains except for a P1484S substitution in a China I sub-lineage strain of Asian lineage, which eliminated the reactivity of the epitope with mAb 3F3. However, the epitope ¹⁶⁵⁹RALSK¹⁶⁶³ was only completely conserved in the Africa-2 and Indian lineages, and a single A1660T substitution, mainly appeared in strains of the China I belonging to Asian lineage and a Cosmopolitan lineage strain, still retained the reactivity of the epitope with mAb 3A6. While both A1660T and K1663R substitutions in a China I lineage strain, single K1663R/Q substitution in some China II strains of Asian lineage and some Arctic-like lineage strains and R1659Q mutation in a strain of Africa-3 lineage eliminated the reactivity of the epitope with mAb 3A6, suggesting mAb 3A6 could be used for differentiation of variable epitopes of some strains in different lineages. Thus, variability and conservation of the three epitopes of L protein showed the reactive difference of mAbs among RABV strains of different lineages. These results may facilitate future studies in development of detection methods for RABV infection, the structure and function of RABV L protein.     

Structural Basis for the Immunogenicity of the C-Terminus of VP1 of Echovirus 3 Revealed by the Binding of a Neutralizing Antibody

Echovirus 3 (E3), a serotype of human enterovirus B (HEV-B), causes severe diseases in infants. Here, we determined the structures of E3 with a monoclonal antibody (MAb) 6D10 by cryo-EM to comprehensively understand the specificities and the immunological characteristic of this serotype. The solved cryo-EM structures of the F-, A-, and E-particles of E3 bound with 6D10 revealed the structural features of the virus–antibody interface. Importantly, the structures of E-particles bound with 6D10 revealed for the first time the nature of the C-terminus of VP1 for HEV-Bs at the structural level. The highly immunogenic nature of this region in the E-particles provides new strategies for vaccine development for HEV-Bs.     

日本血吸虫重组信号蛋白14-3-3的纯化及抗体制备

目的制备日本血吸虫(中国大陆株)信号蛋白Sj14-3-3的多克隆抗体与单克隆抗体。方法将合Sj14-3-3重组蛋白的凝胶条带冻干磨粉,免疫家兔,制备抗Sj14-3-3多克隆抗血请;用电洗脱纯化的Sj14-3-3免疫BALB/c小鼠,用杂交瘤技术制备抗Sj14-3-3单克隆抗体。测定所得抗体效价及特异性鉴定。结果获得大量纯化的表达产物;制备的多克隆抗血清双扩效价达1:8～1:64。获得1株能稳定分泌抗Sj14-3-3单抗的杂交瘤细胞株4D9,单抗亚类为IgG1。此株单抗能与重组Sj14-3-3蛋白发生特异性反应。结论获得了高度敏感、特异的抗Sj14-3-3多克隆抗血清及稳定分泌抗Sj14-3-3单抗的杂交瘤细胞。     

Characterization of Neutralizing Monoclonal Antibodies and Identification of a Novel Conserved C-Terminal Linear Epitope on the Hemagglutinin Protein of the H9N2 Avian Influenza Virus

The H9N2 avian influenza virus (AIV) remains a serious threat to the global poultry industry and public health. The hemagglutinin (HA) protein is an essential protective antigen of AIVs and a major target of neutralizing antibodies and vaccines. Therefore, in this study, we used rice-derived HA protein as an immunogen to generate monoclonal antibodies (mAbs) and screened them using an immunoperoxidase monolayer assay and indirect enzyme-linked immunosorbent assay. Eight mAbs reacted well with the recombinant H9N2 AIV and HA protein, four of which exhibited potent inhibitory activity against hemagglutination, while three showed remarkable neutralization capacities. Western blotting confirmed that two mAbs bound to the HA protein. Linear epitopes were identified using the mAbs; a novel linear epitope, ⁴⁸⁰HKCDDQCM⁴⁸⁷, was identified. Structural analysis revealed that the novel linear epitope is located at the C-terminus of HA2 near the disulfide bond-linked HA1 and HA2. Alignment of the amino acid sequences showed that the epitope was highly conserved among multiple H9N2 AIV strains. The results of this study provide novel insights for refining vaccine and diagnostic strategies and expand our understanding of the immune response against AIV.     

Identification of Unique and Conserved Neutralizing Epitopes of Vestigial Esterase Domain in HA Protein of the H9N2 Subtype of Avian Influenza Virus

The H9N2 subtype of avian influenza virus (AIV) has been reported to infect not only birds, but also humans. The hemagglutinin (HA) protein is the main surface antigen of AIV and plays an important role in the viral infection. For treatment strategies and vaccine development, HA protein has been an important target for the development of broadly neutralizing antibodies against influenza A virus. To investigate the vital target determinant cluster in HA protein in this work, HA gene was cloned and expressed in the prokaryotic expression vector pET28a. The spleen lymphocytes from BALC/c mice immunized with the purified recombinant HA protein were fused with SP2/0 cells. After Hypoxanthine-Aminopterin-Thymidine (HAT) medium screening and indirect ELISA detection, six hybridoma cell lines producing anti-HA monoclonal antibodies were screened. The gradually truncated HA gene expression and western blotting were used to identify their major locations in epitopes specific to these monoclonal antibodies. It was found that the epitopes were located in three areas: ¹¹²NVENLEEL¹¹⁹, ¹¹⁷EELRSLFS¹²⁴, and ¹⁷⁰PIQDAQ¹⁷⁵. Epitope ¹¹²NVENLEEL¹¹⁹ has a partial amino acid crossover with ¹¹⁷EELRSLFS¹²⁴, which is located in the vestigial esterase domain “110-helix” of HA, and the monoclonal antibody recognizing these epitopes showed the neutralizing activity, suggesting that the region ¹¹²NVENLEELRSLFS¹²⁴ might be a novel neutralizing epitope. The results of the homology analysis showed that these three epitopes were generally conserved in H9N2 subtype AIV, and will provide valuable insights into H9N2 vaccine design and improvement, as well as antibody-based therapies for treatment of H9N2 AIV infection.     

Identification of Human Norovirus GII.3 Blockade Antibody Epitopes

Human noroviruses are a common pathogen causing acute gastroenteritis worldwide. Among all norovirus genotypes, GII.3 is particularly prevalent in the pediatric population. Here we report the identification of two distinct blockade antibody epitopes on the GII.3 capsid. We generated a panel of monoclonal antibodies (mAbs) from mice immunized with virus-like particle (VLP) of a GII.3 cluster 3 strain. Two of these mAbs, namely 8C7 and 8D1, specifically bound the parental GII.3 VLP but not VLPs of GII.4, GII.17, or GI.1. In addition, 8C7 and 8D1 efficiently blocked GII.3 VLP binding with its ligand, histo-blood group antigens (HBGA). These data demonstrate that 8C7 and 8D1 are GII.3-specific blockade antibodies. By using a series of chimeric VLPs, we mapped the epitopes of 8C7 and 8D1 to residues 385–400 and 401–420 of the VP1 capsid protein, respectively. These two blockade antibody epitopes are highly conserved among GII.3 cluster 3 strains. Structural modeling shows that the 8C7 epitope partially overlaps with the HBGA binding site (HBS) while the 8D1 epitope is spatially adjacent to HBS. These findings may enhance our understanding of the immunology and evolution of GII.3 noroviruses.     

抗环子孢子蛋白保守II~ 区单克隆抗体的制备及鉴定

目的　获得针对恶性疟原虫环子孢子蛋白 (CSP)保守II 区 (RegionII )的单克隆抗体。　方法　采用恶性疟原虫保守II 区十二肽 (EWSPCSVTCGNG)免疫BALB/c小鼠 ,经融合 ,ELISA 3次筛选 ,获得 3株分泌针对保守II 区单克隆抗体的杂交瘤细胞株。　结果　ELISA检测结果显示单抗能与重组表达的恶性疟原虫CSP片段及天然CSP特异性反应。间接荧光抗体检测显示 ,单抗不仅能识别恶性疟原虫子孢子 ,也能识别约氏疟原虫子孢子。　结论　成功地获得了针对恶性疟原虫CSP保守II 区的单克隆抗体     

Comparative Proteomic Profiling: Cellular Metabolisms Are Mainly Affected in Senecavirus A-Inoculated Cells at an Early Stage of Infection

Senecavirus A (SVA), also known as Seneca Valley virus, belongs to the genus Senecavirus in the family Picornaviridae. SVA can cause vesicular disease and epidemic transient neonatal losses in pigs. This virus efficiently propagates in some non-pig-derived cells, like the baby hamster kidney (BHK) cell line and its derivate (BSR-T7/5). Conventionally, a few proteins or only one protein is selected for exploiting a given mechanism concerning cellular regulation after SVA infection in vitro. Proteomics plays a vital role in the analysis of protein profiling, protein-protein interactions, and protein-directed metabolisms, among others. Tandem mass tag-labeled liquid chromatography-tandem mass spectrometry combined with the parallel reaction monitoring technique is increasingly used for proteomic research. In this study, this combined method was used to uncover separately proteomic profiles of SVA- and non-infected BSR-T7/5 cells. Furthermore, both proteomic profiles were compared with each other. The proteomic profiling showed that a total of 361 differentially expressed proteins were identified, out of which, 305 and 56 were upregulated and downregulated in SVA-infected cells at 12 h post-inoculation, respectively. GO (Gene Ontology) and KEGG (Kyoto Encyclopedia of Genes and Genomes) enrichment analyses showed that cellular metabolisms were affected mainly in SVA-inoculated cells at an early stage of infection. Therefore, an integrated metabolic atlas remains to be explored via metabolomic methods.     

抗日本血吸虫14?3?3蛋白单克隆抗体5C6抗原识别表位的鉴定

目的 目的 采用噬菌体展示肽技术鉴定抗日本血吸虫14?3?3蛋白单克隆抗体5C6的抗原识别表位。 方法 方法 将纯化的抗日本血吸虫14?3?3蛋白单克隆抗体5C6作为固相配基筛选噬菌体随机展示12肽库, 按照吸附?洗脱?扩增的淘洗过程进行3轮生物淘洗, 富集特异性结合的噬菌体颗粒。随机挑取第3轮洗脱的独立噬菌体克隆, 分别依次进行噬菌体扩增、基因组DNA抽提和DNA序列分析。选择外源性插入DNA序列完全相同或高度相似的同源性噬菌体, 采用ELISA及免疫印迹分析对其免疫反应性作进一步鉴定, 以确定单克隆抗体5C6的抗原识别表位。 结果 结果 第3轮淘洗物中33个独立噬菌体克隆的DNA测序结果显示, 其中25个噬菌体编码外源性插入肽的核酸序列均为5′?CCACCTAGTAGCAGACCGATTCT? CAGTCGAAGGAAA?3′, 其对应的演绎氨基酸序列为PPSSRPILSRRK, 该肽与日本血吸虫信号蛋白14?3?3及自然界其他已知蛋白的氨基酸序列均无同源性。免疫印迹试验证实此短肽可被自然感染的日本血吸虫病人血清所识别, 而不与健康人血清反应。 结论 结论 本研究成功鉴定了抗日本血吸虫14?3?3蛋白单克隆抗体5C6所识别的模拟抗原表位, 并证明该表位为空间构像表位。     

Novel Neutralizing Epitope of PEDV S1 Protein Identified by IgM Monoclonal Antibody

Porcine epidemic diarrhea virus (PEDV) causes devastating enteric disease that inflicts huge economic damage on the swine industry worldwide. A safe and highly effective PEDV vaccine that contains only the virus-neutralizing epitopes (not enhancing epitope), as well as a ready-to-use PEDV neutralizing antibody for the passive immunization of PEDV vulnerable piglets (during the first week of life) are needed, particularly for PEDV-endemic farms. In this study, we generated monoclonal antibodies (mAbs) to the recombinant S1 domain of PEDV spike (S) protein and tested their PEDV neutralizing activity by CPE-reduction assay. The mAb secreted by one hybrodoma clone (A3), that also bound to the native S1 counterpart from PEDV-infected cells (tested by combined co-immunoprecipitation and Western blotting), neutralized PEDV infectivity. Epitope of the neutralizing mAb (mAbA3) locates in the S1A subdomain of the spike protein, as identified by phage mimotope search and multiple sequence alignment, and peptide binding-ELISA. The newly identified epitope is shared by PEDV G1 and G2 strains and other alphacoronaviruses. In summary, mAbA3 may be useful as a ready-to-use antibody for passive immunization of PEDV-susceptible piglets, while the novel neutralizing epitope, together with other, previously known protective epitopes, have potential as an immunogenic cocktail for a safe, next-generation PEDV vaccine.     

The Stem-Loop I of Senecavirus A IRES Is Essential for Cap-Independent Translation Activity and Virus Recovery

Senecavirus A (SVA) is a picornavirus that causes vesicular disease in swine and the only member of the Senecavirus genus. Like in all members of Picornaviridae, the 5′ untranslated region (5’UTR) of SVA contains an internal ribosome entry site (IRES) that initiates cap-independent translation. For example, the replacement of the IRES of foot-and-mouth disease virus (FMDV) with its relative bovine rhinitis B virus (BRBV) affects the viral translation efficiency and virulence. Structurally, the IRES from SVA resembles that of hepatitis C virus (HCV), a flavivirus. Given the roles of the IRES in cap-independent translation for picornaviruses, we sought to functionally characterize the IRES of this genus by studying chimeric viruses generated by exchanging the native SVA IRES with that of HCV either entirely or individual domains. First, the results showed that a chimeric SVA virus harboring the IRES from HCV, H-SVA, is viable and replicated normally in rodent-derived BHK-21 cells but displays replication defects in porcine-derived ST cells. In the generation of chimeric viruses in which domain-specific elements from SVA were replaced with those of HCV, we identified an essential role for the stem-loop I element for IRES activity and recombinant virus recovery. Furthermore, a series of stem-loop I mutants allowed us to functionally characterize discrete IRES regions and correlate impaired IRES activities, using reporter systems with our inability to recover recombinant viruses in two different cell types. Interestingly, mutant viruses harboring partially defective IRES were viable. However, no discernable replication differences were observed, relative to the wild-type virus, suggesting the cooperation of additional factors, such as intermolecular viral RNA interactions, act in concert in regulating IRES-dependent translation during infection. Altogether, we found that the stem-loop I of SVA is an essential element for IRES-dependent translation activity and viral replication.     

禽流感病毒M1蛋白型特异性表位分析

目的对流感病毒基质蛋白1(M1)型特异性表位进行定位研究。方法采用针对禽流感病毒M1蛋白的型特异性单克隆抗体,淘选M13噬菌体展示的12肽随机肽库,进行M1蛋白表(拟)位分析。采用ELISA、竞争性ELISA、免疫印迹分析不同噬菌体拟位与单克隆抗体的免疫反应性。结果筛选获得共有序列NxPHLR,定位于M1蛋白222-224位(HPN)、229-230位(LR)氨基酸区域。含有NxPHLR基序的噬菌体拟位能与单克隆抗体发生特异性结合,且此结合能被天然病毒抗原抑制或阻断,表明拟位多肽真实模拟了天然病毒蛋白与单克隆抗体结合的抗原决定簇或表位。结论M1蛋白222-230位氨基酸(HPNSSARLR)序列构成了流感病毒型特异性表位。     

肠道病毒71型VP1蛋白二级结构及B细胞表位的预测

目的预测C4基因亚型肠道病毒71型的VP1蛋白二级结构及B细胞表位,为EV71疫苗研制提供理论基础。方法本研究将宁波地区EV71分离株与国内外EV71代表株进行同源性分析和并构建亲缘进化树。以VP1基因序列为材料,应用EX-PASY服务器上的GOR4、SOPMA两种方法分析预测蛋白质二级结构,并结合蛋白质的亲水性、柔韧性、表面可能性等指标综合评价VP1蛋白的B细胞抗原表位。结果同源性分析和亲缘进化分析得出,2010年宁波EV71分离株属于C4a基因亚型,与基因库检索到的C4a基因亚型代表株核苷酸和氨基酸同源性较高,分别为93.6%～99.3%和98.3%～100%。VP1蛋白二级结构以无规则卷曲和β-片层为主,有多处抗原指数较高的区段,结合亲水性、柔韧性、表面可能性等指标,综合预测VP1蛋白的B细胞抗原表位在第39～40、159～167、212～220、287～290位氨基酸残基的可能性较大。结论 EV71VP1蛋白多个区段具有抗原潜力通过生物信息学方法预测VP1蛋白二级结构及B细胞表位为EV71疫苗研制提供理论基础。     

日本血吸虫信号蛋白14-3-3的虫体免疫定位

目的　研究抗重组日本血吸虫信号蛋白1433(rSj1433)单克隆抗体对天然Sjl433的结合活性,观察Sj1433在虫体内的定位。　方法　从阳性钉螺体内逸出尾蚴,感染家兔,分别于感染后15d和42d剖杀,静脉灌注法收集童虫和成虫制备冰冻切片。利用rSj1433单克隆抗体,间接免疫荧光法探讨信号蛋白1433虫体内的分布。　结果　免疫荧光染色结果显示,rSj1433单克隆抗体可特异性地结合天然Sj1433抗原表位,背景清晰,Sj1433广泛分布在雌、雄成虫的皮层、皮下层、肌层和实质层,前三种组织中特异性荧光呈线状分布,实质中特异性荧光弥散;童虫中Sj1433也广泛的分布在皮层、皮下层、肌层和实质层。　结论　免疫荧光染色成功地确定了Sj1433蛋白在成虫和15d童虫体内的分布     

耶尔森氏菌YadA蛋白单克隆抗体的研制与鉴定

１．以纯化的ＹａｄＡ蛋白免疫普通小鼠４只，获得小鼠ＹａｄＡ多克隆抗血清；２．利用上述免疫血清建立了ＹａｄＡ多克隆缺本的ＥＬＩＳＡ检测技术，并对其最适条件进行了观察；３．用纯化的ＹａｄＡ蛋白免疫ＢＡＬＢ／Ｃ小鼠２只，以免疫ＢＡＬＢ／Ｃ小鼠的脾细胞与骨髓瘤细胞系ＳＰ２／０融合，获得１７株分泌ＹａｄＡ－ＭｃＡｂ杂交瘤细胞株，将其中４株进行了再克隆，经过半年左右的反复传代及冷冻，复苏测试，抗体分泌稳定，４