Serological profiling of Crohn’s disease and ulcerative colitis patients reveals anti-microbial antibody signatures

BACKGROUND The healthcare burden of inflammatory bowel disease(IBD)is rising globally and there are limited non-invasive biomarkers for accurate and early diagnosis.AIM To understand the important role that intestinal microbiota play in IBD pathogenesis and identify anti-microbial antibody signatures that benefit clinical management of IBD patients.METHODS We performed serological profiling of 100 Crohn’s disease(CD)patients,100 ulcerative colitis(UC)patients and 100 healthy controls against 1173 bacterial and 397 viral proteins from 50 bacteria and 33 viruses on protein microarrays.The study subjects were randomly divided into discovery(n=150)and validation(n=150)sets.Statistical analysis was performed using R packages.RESULTS Anti-bacterial antibody responses showed greater differential prevalence among the three subject groups than anti-viral antibody responses.We identified novel antibodies against the antigens of Bacteroidetes vulgatus(BVU_0562)and Streptococcus pneumoniae(SP_1992)showing higher prevalence in CD patients relative to healthy controls.We also identified antibodies against the antigen of Streptococcus pyogenes(SPy_2009)showing higher prevalence in healthy controls relative to UC patients.Using these novel antibodies,we built biomarker panels with area under the curve(AUC)of 0.81,0.87,and 0.82 distinguishing CD vs control,UC vs control,and CD vs UC,respectively.Subgroup analysis revealed that penetrating CD behavior,colonic CD location,CD patients with a history of surgery,and extensive UC exhibited highest antibody prevalence among all patients.We demonstrated that autoantibodies and anti-microbial antibodies in CD patients had minimal correlation.CONCLUSION We have identified antibody signatures for CD and UC using a comprehensive analysis of antimicrobial antibody response in IBD.These antibodies and the source microorganisms of their target antigens improve our understanding of the role of specific microorganisms in IBD pathogenesis and,after future validation,should aid early and accurate diagnosis of IBD.

Serum Helicobacter pylori Kat A and Ahp C antibodies as novel biomarkers for gastric cancer

AIM: To investigate catalase(Kat A) and alkyl hydroperoxide reductase(Ahp C) antibodies of Helicobacter pylori as biomarkers for gastric cancer(GC).METHODS: This study included 232 cases and 264 controls. Recombinant Kat A and Ahp C proteins were constructed and the levels of antibodies were tested by indirect enzyme-linked immunosorbent assay(ELISA). Logistic regression was applied to analyze the relationships between Kat A, Ahp C and GC. The χ2 trend test was used to evaluate the dose-response relationships between serum Kat A and Ahp C antibody levels and GC. Receiver operating characteristic(ROC) curve was used to evaluate the screening accuracy of Kat A and Ahp C as biomarkers. Combined analysis was used to observe screening accuracy of predictors for GC.RESULTS: In all subjects, the association between Kat A and Ahp C and GC risk was significant(P < 0.001) with odds ratio(OR) = 12.84(95%CI: 7.79-21.15)and OR = 2.4(95%CI: 1.55-3.73), respectively. Kat A and Ahp C antibody levels were strongly related to GC risk with a dose-dependent effect(P for trend < 0.001). The area under the ROC(AUC) for Kat A was 0.806, providing a sensitivity of 66.81% and specificity of 86.36%; and the AUC for Ahp C was 0.615, with a sensitivity of 75.65% and specificity of 45.49%. The AUC was 0.906 for Kat A and flagella protein A(Fla A) combined analysis.CONCLUSION: Serum Kat A and Ahp C antibodies are associated with GC risk and Kat A may serve as a biomarker for GC. Kat A/Fla A combined analysis improved screening accuracy.

<i>Blastomyces dermatitidis</i>Antibody Responses in Serial Serum Specimens from Dogs with Blastomycosis: Comparison of Different Yeast Lysate Antigens

The systemic fungal organism, Blastomyces dermatitidis causes blastomycosis in animals and hu-mans. This study was designed to evaluate antibody detection in 55 serial serum specimens from 9 dogs with blastomycosis using B. dermatitidis yeast lysate antigens produced from two human isolates (B5896;B5931) and two dog isolates (ERC-2;T-58) with the indirect enzyme linked im-munosorbent assay (ELISA;peroxidase system) to determine an optimal lysate antigen(s) for use in the ELISA to detect antibody in the dog serum specimens. The mean absorbance values when the lysate antigens were compared with respect to their ability to detect antibody in the day 0 sera from the 9 dogs were 1.024 (ERC-2), 1.351 (B5896), 1.700 (B5931) and 2.084 (T-58) respectively. All of the reagents exhibited a high level of sensitivity and in all instances the amount of antibody declined as the time interval post-treatment increased, but the T-58 lysate prepared from the dog isolate from Tennessee was the optimal reagent. We continue to evaluate antigens for B. derma-titidis antibody detection in different immunodiagnostic assays.

Changes of serum p53 antibodies and clinical signifi cance of radiotherapy for esophageal squamous cell carcinoma

AIM: To explore the relationship between serum p53 antibodies (p53-Abs) and clinicopathological characteristics and therapeutic effect in patients with esophageal carcinoma (EC), and to investigate sequential changing regularity of serum p53-Abs after radiotherapy. METHODS: The serum p53-Ab levels were detected in 46 EC patients and 30 healthy adults by enzyme linked immunosorbent assay (ELISA). The blood samples were collected on the day before radiotherapy and on the administration of an irradiation dose of 20 Gy/10 f/12 d, 40 Gy/20 f/24 d and 60 Gy/30 f/36 d after radiotherapy. RESULTS: The level and positive rate of serum p53-Abs in EC patients were significantly higher than those in normal individuals (P < 0.05). Serum anti-p53 antibodies were positive in 18 of 46 EC patients (39.1%). The positive rate of p53-Abs in EC was related to histological grade, disease stage and lymph node metastasis (P < 0.05), but it was not signif icantly related to sex, age and to the size and site of tumor. The level and positive rate of p53-Abs had signif icant differences between before radiotherapy and after administration of an irradiation dose of 40 Gy/20 f/24 d and 60 Gy/30 f/36 d (P < 0.05 or P < 0.01). The positive rate of p53-Abs in EC patients with effect was significantly lower than that in those without effect after radiotherapy (P < 0.0001).CONCLUSION: Detection of serum p53-Abs is helpful to the diagnosis of esophageal carcinoma. Monitoring for sequential change of serum p53-Abs before and after radiotherapy in patients with esophageal carcinoma is also useful to evaluate the response to the treatment and prognosis of the patients.

Screening of Serum Dilution and Determination of Normal Range of Antibodies against Rabies Viruses in Dog Sera

[ Objective] To screen a suitable serum dilution and determine the normal range of antibodies against rabies viruses （RV） in dog serum. [Method]A sensitive, specific and suitable serum dilution was screened. A total of 812 dog serum samples were collected from Changchun, Nanning and Uuzhou regions, and then they were diluted with above screened serum dilution and evaluated by indirect enzyme-linked immunosorbont assay （ELISA）. The positive and negative standard dog sara from the World Organization for Animal Health （OIE） were used as controls. The serum samples with different A450 were randomly selected and the anti-RV serum titers were detected by rapid fluorescent focus inhibition test （RFFIT）. According to the A450 of dog sera, the normal A450 range of negative serum and 95% confidence intervals were calculated with SPSS 10.0 software, and the regression equation of OIE standards was established. [ Result] The screened serum dilution was sensitive and specific; at least 756 negative serum samples were obtained; the normal range and 95% confidence interval of negative serum were 0.127 3 ± 0.059 8 and 0.078 1 -0.172 3, respectively; and the regression equation was A450 = 1.139 serum titer （IU） ±0.470. [ Conclusion] These results lay a foundation for thecontrolling of dog rabies endemic and the development of ELISA kits of dog antibodies against RV.

Detection of Serum Antibodies of Porcine Pseudorabies Virus(PRV)in Binzhou City in 2014

To understand immunization effect of pseudorabies vaccine and infection status of porcine pseudorabies （PR） in pig farms and guide prevention and control against PR, 453 copies of blood samples collected from 43 different scale pig farms in four counties （districts） of Binzhou City were detected with ELISA to investigate PRV gB antibody and gE antibody. Detection results showed that the gB antibody positive rate of sows was 75.58%, and that of fattening pigs was 68.67% ; the pig farms with positive rate higher than 70% accounted for 74.42% of total survey pig farms. The PRV gE antibody positive rates of sows and fatte- ning pigs were 25.41% and 26.67%, and the positive rates of pig farms were 46.51% and 44.33%, respectively. There were regional differences among counties （districts）.

Role of GM3 ganglioside in the pathology of some progressive human diseases and prognostic importance of serum anti-GM3 antibodies

Glycosphingolipids(gangliosides)have been characterized as important biological molecules with a key role as regulators in many physiological processes on cellular,tissue,organ,and organism levels.The deviations in their normal amounts,production,and metabolism are very often related to the development of many multi-factor socially important diseases.GM3 ganglioside,as a small molecule,plays important roles in the cascade regulatory pathways in the pathology of many disorders like neurodegenerative diseases,autoimmune diseases,inflammation,diabetes,malignant transformation,and others.Ganglioside GM3 and its derivatives are membrane-bound glycosphingolipids composed of an oligosaccharide head structure containing one sialic acid residue.These molecules transduce signals involved in cell surface events,including the phosphorylation of transmembrane receptors.This ganglioside is the most widely distributed among tissues,and it serves as a precursor for most of the more complex ganglioside species.GM3 inhibits the function of fibroblast growth factor receptor,and cell growth is regulated by GM3-enriched microdomain.GM3 is thought to inhibit immunologic functions,such as the proliferation and production of cytokines by T cells.On the other hand,the anti-ganglioside antibodies(AGAs)are important in many acquired demyelinating immunemediated neuropathies,like Multiple sclerosis(MS),Guillain–Barrésyndrome(GBS)and its variation,Miller–Fisher syndrome(MFS)and could be suggested as important diagnostic and prognostic markers about the describe diseases and their etiology.We show that the complexes of anti-ganglioside antibodies to GM3(detected by ELISA)may be useful diagnostic and prognostic tool markers for autoimmune diseases,neurodegenerative disorders,malignancy,diabetes,and inflammation.Our pilot studies suggest increased serum IgG anti-GM3 antibodies titers in patients with secondary progressive MS(SPMS),throat cancer,elder people with diabetes(89–96 years),old Lewis rats(30–33 months),and in the serum of subjected on lead intoxication BALB/c mice treated by salinomycin.We observed no changes in the titers in healthy elder people(89–96 years),in 70-year-old woman on dialysis,in relapsing-remitting MS(RRMS)patients on long-term treatment with Glatiramer acetate,Laquinimod,and Interferons,as well as in 18–22 months old Wistar rats and subjected on lead intoxication BALB/c mice treated by monensin and dimercaptosuccinic acid(DMSA).Considerable decrease of serum GM3 in early MS correlate with early damage and severe destruction of the blood–brain barrier,which provides impetus to initiate early therapy.

Development of a Multi-Plex Electrochemiluminescent Assay for the Detection of Serum Antibody Responses to Meningococcal Conjugate Vaccines

Neisseria meningitidis is a gram negative diplococcal bacterium. Worldwide, N. meningitidis is the leading cause of bacterial meningitis and sepsis, with five serogroups (A, B, C, Y, and W-135) responsible for the majority of the disease. Multivalent (A, C, Y, and W-135) polysaccharide and conjugate vaccines have been licensed in the United States and elsewhere and are widely available. We have developed a multi-plexed electrochemiluminescent assay to quantitate serum antibody responses to meningococcal polysaccharides A, C, Y, and W-135 to allow for rapid evaluation of li- censed and investigational vaccines. A 96-well plate containing a carbon electrode arrayed with polysaccharides A, C, Y, and W-135 on separate spots within each well has been developed for simultaneous detection of polysaccharidespecific antibodies in serum samples from vaccinated individuals. The assay conditions were optimized using the anti-meningococcal serogroup A/C reference serum pool, CDC 1992 (NIBSC 99/706), through evaluation of plate types, coating polysaccharide concentrations, and blocking and serum diluent buffers. Comparison of single and multiplex assays demonstrated the sensitivity, specificity, and speed of the multi-plex format for the quantification of serum antibody responses to N. meningitidis polysaccharides A, C, Y and W-135.

Emergent Serum Therapy and Antibody Medicine to Counteract Sudden Attacks of COVID-19 and Other Pathogenic Epidemics

The science behind two life-saving protocols to combat COVID-19 and future pathogenic epidemics is presented for immediate implementation.

Analysis of Detecting HIV-1 Antibody in Paired Urine and Serum Specimens from Drug Users by ELISA

Objective- To compare the consistency of the results from detecting HIV-1 antibody in the paired urine and serum specimens from drug users by ELISA. Methods: The paired urine and serum specimens from 273 drug users detained at a detoxification unit were collected, and the HIV-1 antibodies in the specimens of them were screened by urine and serum ELISA kits, respectively. Results: Of 273 serum specimens, 94 ones showed positive reaction and among 94 counterpart urine specimens, 93 ones also appeared positive reaction. Taking the results together,the consistent rate of HIV-1 antibody screened by urine and serum ELISA kits was 99.6%. Conclusion: The urine ELISA kit, which screened HIV-1 antibody of urine showing almost the same results tested by serum ELISA kit, is reliable. It is proposed that urine ELISA be introduced in many fields.

2017—2021年云南省猪瘟病原学和血清学监测情况分析

为全面了解2017—2021年云南省猪瘟(CSF)流行及免疫状况,预估疫病流行和发生风险,采集病原学样品63 224份、血清学样品146 547份,进行CSF病原和血清抗体监测。结果显示:2017—2021年云南省CSF免疫抗体合格率分别为82.94%、81.47%、80.79%、80.24%、82.53%,规模场合格率略高于散养户,但差异不显著(P>0.05);CSF病原核酸阳性率分别为0.52%、0.74%、1.10%、1.02%、2.42%,散养户、屠宰场阳性率高于规模场。结果表明:自2017年CSF退出强制免疫后,云南省CSF免疫抗体合格率均达到国家标准,但病原阳性率整体呈上升趋势,且分布范围广,免疫密度低和抗体合格率低的散养户发生CSF的风险较高,提示应对其加强监测和免疫。

新疆某规模化猪场3种病毒病抗体监测分析与免疫程序优化

该试验旨在了解当前新疆巴州某规模化猪场猪瘟(CSF)、猪蓝耳病(PRRS)和伪狂犬(PR)疫苗的免疫水平,收集当地某规模化生猪养殖场的467个血清样品,采用ELISA抗体检测试剂盒检测血清中猪瘟、猪蓝耳病和猪伪狂犬病毒的抗体水平。结果显示,该地区的猪瘟、猪蓝耳病和猪伪狂犬病毒平均血清抗体阳性率分别为93.68%、77.22%和92.65%,均超过我国强制性疫苗免疫抗体阳性率标准70%。该地区猪群免疫手段还有很大的进步空间,本研究结合该地区实际情况对免疫程序进行了相应的调整优化。

白喉毒素突变体CRM197在大肠杆菌中优化表达及人群血清抗体水平分析

目的 构建白喉毒素突变体CRM197的原核表达载体,在大肠杆菌中表达CRM197蛋白。分析健康人群血清中的CRM197抗体水平。方法 对CRM197基因进行大肠杆菌密码子优化并克隆至pET28a(+)中,经表达条件优化后采用镍柱亲和层析和离子交换层析对重组蛋白CRM197进行纯化,对纯化的CRM197进行Western blot鉴定。最后,经纯化后的CRM197蛋白与健康人群血清进行反应,检测人群血清中针对该蛋白的抗体水平。结果 CRM197蛋白进行了密码子及表达条件优化后,获得了可溶性表达蛋白。经镍柱亲和层析和离子交换层析后其纯度可达95%以上,Western Blot鉴定后能得到单一的特异性条带。经纯化的CRM197蛋白与不同年龄阶段健康人群血清均发生不同程度的抗原抗体反应。结论 利用本研究的策略,CRM197得到高效的可溶性表达,但人群血清中含有高水平的CRM197抗体,这些抗体的存在可能会影响到应用CRM197结合多糖作为抗原进行特异免疫效果的评价以及作为诊断抗原的应用。

先兆流产患者保胎结局影响因素及与血清sHLA-G、ACA水平关系

目的:探索先兆流产患者保胎结局的影响因素,并分析其与血清可溶性人白细胞抗原-G(sHLA-G)、抗心磷脂抗体(ACA)的关系。方法:回顾性收集2021年6月-2023年6月本院收治的80例先兆流产患者临床资料,根据保胎结局分为保胎失败组与保胎成功组,对比两组一般资料,酶联免疫吸附法检测两组sHLA-G、ACA水平,经单因素及Pearson相关性分析法探讨先兆流产保胎结局的影响因素及与血清sHLA-G、ACA水平关系。结果:两组年龄、既往流产史、合并阴道炎、生殖道感染、妊娠期糖尿病、接触有毒化学物质等方面有差异;保胎失败组sHLA-G(7.43±1.20 U/ml)水平低于保胎成功组(50.14±4.56 U/ml),ACA阳性率(74.1%)高于保胎成功组(20.8%)(均P<0.05)。logistic回归分析,高龄、既往流产史、合并阴道炎、生殖道感染、妊娠期糖尿病、接触有毒化学物质、sHLA-G水平低、ACA阳性率高均是影响先兆流产患者保胎结局的重要因素;Pearson相关性分析,年龄、既往流产史、合并阴道炎、生殖道感染、妊娠期糖尿病、接触有毒化学物质与血清sHLA-G水平呈负相关,与ACA阳性率呈正相关(均P<0.05)。结论:先兆流产患者保胎结局可能与高龄、既往流产史、合并阴道炎、生殖道感染、妊娠期糖尿病、接触有毒化学物质、sHLA-G水平及ACA阳性率有关,临床可针对上述因素给予密切关注,并通过监测sHLA-G水平及ACA阳性率的变化来指导临床早期干预,以确保母婴安全。

TPO-Ab、FT3/FT4比值、TBiL水平与急性缺血性脑卒中患者短期预后的关系研究

目的 探究甲状腺过氧化物酶抗体(thyroid peroxidase antibodies, TPO-Ab)、游离三碘甲状腺原氨酸(free triiodothyronine, FT3)和游离甲状腺素(free thyroxine, FT4)的比值(FT3/FT4)、血清总胆红素(total bilirubin, TBiL)水平与急性缺血性脑卒中(acute ischemic stroke, AIS)患者短期预后的关系。方法 回顾性选取2021年3月~2023年5月在蒙城县第一人民医院接受治疗的124例急性缺血性脑卒中患者,治疗3个月后根据改良Rankin量表(modified rankin scale, mRS)评分分为良好预后组(82例)和预后不良组(42例)。使用单因素及多因素logistic回归分析TPO-Ab、FT3/FT4比值、TBiL水平及其他相关因素对急性缺血性脑卒中患者短期预后的影响,并且构建患者不良预后预测模型,模型准确度以ROC曲线判断。结果 多因素分析结果显示,两组患者年龄(OR=2.045,95%CI=1.159~3.608,P=0.014)、美国卫生研究院卒中量表(NIHSS)(OR=1.805,95%CI=1.058~3.079,P=0.030)、TBiL(OR=0.620,95%CI=0.418~0.922,P=0.018)、FT3/FT4(OR=0.244,95%CI=0.088~0.679,P=0.007)、TPO-Ab(OR=3.242,95%CI=1.312~8.009,P=0.011)均为患者预后不良的独立影响因素(P<0.05)。在此基础上建立风险预测模型,模型公式:Logit(P)=-42.915+0.715×年龄+0.591×NIHSS-0.477×TBiL-1.409×FT3/FT4+1.176×TPO-Ab。其ROC曲线下面积为0.996,95%CI=0.991~1.000-,敏感度为1.000,特异度为0.963,Youden指数为0.963。结论 TPO-Ab、FT3/FT4比值、TBiL水平均为急性缺血性脑卒中患者短期预后不良的独立影响因素,在此基础上建立的联合预测模型预测效能良好。

NT与血清β-hCG、PAPP-A、ADAM12单独及联合检测对孕早期DS的诊断价值

目的:探讨颈部透明层厚度(NT)与血清人绒毛膜促性腺激素(β-hCG)、妊娠相关蛋白A(PAPP-A)及解整合素金属蛋白酶12(ADAM12)单独及联合检测对孕早期唐氏综合征(DS)的诊断价值。方法:选取2019年1月—2023年1月在厦门大学附属第一医院杏林分院经羊膜穿刺确诊的47例DS孕妇作为DS组,另选取同期49例产前检查正常的孕产妇作为对照组,检测并比较两组NT及血清β-hCG、PAPP-A、ADAM12水平,并采用受试者工作特征(ROC)曲线分析NT与血清β-hCG、PAPP-A、ADAM12单独及联合检测对DS的诊断价值。结果:DS组NT及血清β-hCG水平高于对照组,PAPP-A、ADAM12水平均低于对照组,差异有统计学意义(P<0.05)。ROC曲线分析显示,NT与血清β-hCG、PAPP-A、ADAM12联合检测诊断DS的曲线下面积为0.993,预测敏感度、特异度分别为95.7%、98.0%,均高于上述指标单独检测。结论:NT与血清β-hCG、PAPP-A、ADAM12检测对孕早期DS均具有一定的诊断价值,且联合应用诊断效果更高,可作为孕早期DS筛查的有效指标。

抗CCL20单克隆抗体对血清淀粉样蛋白A相关的结节病中促炎性细胞因子的抑制作用

目的探讨抗CCL20单克隆抗体是否可抑制高水平血清淀粉样蛋白A(SAA)相关的结节病外周血单个核细胞(PBMC)中促炎性细胞因子的表达。方法提取健康人和结节病患者的PBMC,并进行分组。除空白对照组(正常人PBMC)和结节病PBMC对照组(患者PBMC)外,另将结节病组PBMC中分别加入SAA、SAA+抗CCL20单克隆抗体、SAA+NF-κB抑制剂BAY11-7082或地塞米松,经培养48 h后收集各组细胞,分别作为PBMC+SAA刺激组、PBMC+SAA+NF-κB抑制剂BAY11-7082组、PBMC+SAA+抗CCL20单抗组、PBMC+地塞米松干预组,使用ELISA分别测定各组细胞上清液中细胞因子IL-17A、IL-23、IL-6、CCL20和TGF-β1的表达,使用RT-PCR测定各组细胞中CCR6、IL-17、ROR-γt和Foxp3的mRNA表达水平,使用Western blot检测各组细胞中p-NF-κB和NF-κB蛋白的表达水平。结果PBMC+SAA+抗CCL20单抗组与PBMC+SAA组相比,细胞上清液中的IL-17A、IL-23和IL-6的水平显著降低(P<0.01),而TGF-β1的含量显著升高(P<0.01)。PBMC+SAA+抗CCL20单抗组相较于PBMC+SAA组,细胞中CCR6、IL-17A、ROR-γtmRNA水平显著降低(P<0.01),而Foxp3 mRNA差异无统计学意义(P>0.05)。PBMC+SAA+抗CCL20单抗组中p-NF-κB蛋白表达水平较PBMC+SAA组明显降低(P<0.01)。结论抗CCL20单克隆抗体可抑制高水平SAA相关的结节病PBMC中促炎性细胞因子的表达。

新型冠状病毒感染康复者和接种新型冠状病毒疫苗的未感染者血清抗体分析

目的探讨新型冠状病毒(新冠病毒)感染康复者和接种新冠病毒疫苗的未感染者血清免疫球蛋白(immunoglobulin,Ig)M、IgG、中和抗体水平及特征。方法选取2022年12月9日至2023年1月31日在昆明市第三人民医院的医务工作者为研究对象,其中新冠病毒感染康复者36例(康复组),接种新冠病毒疫苗的未感染者33例(疫苗组),检测2组血清抗体并分析。结果康复组和疫苗组IgM阳性率分别为25.00%、18.19%,IgG和中和抗体阳性率均为100%,2组阳性率差异均无统计学意义(P均>0.05)。康复组IgG和中和抗体水平均高于疫苗组(P均<0.05),但2组IgM水平差异无统计学意义(P>0.05)。2组女性IgG水平均高于男性(P均<0.05),中和抗体水平男性均高于女性(P均<0.05)。结论新冠病毒感染康复人群IgG、中和抗体水平高于疫苗接种人群。新冠病毒感染康复者和接种新冠病毒疫苗的未感染者IgG水平女性高于男性。

鸡新城疫抗体消长规律及血清抗体稳定性

为研究鸡新城疫灭活疫苗免疫后抗体消长规律及血清抗体稳定性,采用血凝抑制试验方法测定新城疫病毒-禽流感病毒(H9亚型)二联灭活疫苗免疫鸡血清新城疫抗体效价及经室温、4℃、-20℃、-80℃反复冻融和加热等不同方式处理的血清中新城疫抗体效价。结果表明,试验鸡于1日龄和21日龄用灭活疫苗免疫两次后,在第二次免疫后14 d新城疫抗体平均效价达到8.1 log_(2),35 d达到最高值为8.9 log_(2);免疫后70 d抗体效价保持在7.8 log_(2),且自二免后14~70 d,新城疫抗体效价维持在7.8 log_(2)~8.9 log_(2)。血清新城疫抗体在室温和4℃相对稳定,室温下放置13 d对新城疫抗体效价几乎无影响;但4℃保存9 d,对新城疫抗体效价有一定影响,且差异显著(P<0.05);56℃下30 min对新城疫抗体效价无影响;反复冻融3次对新城疫抗体效价影响极显著(P<0.01)。肉鸡于1日龄和21日龄用灭活疫苗免疫两次后,新城疫抗体水平高,且高水平抗体维持时间长。鸡血清新城疫抗体可耐56℃加热,室温保存活性稳定,反复冻融则影响其效价。