Detection of Antinuclear Antibodies in Canine Serum by Immunoperoxidase in MDCK and Indirect Immunofluorescence in HEp2 Cells

Antinuclear antibodies are found in animals suffering from Systemic Lupus Erythematosus (SLE) and some other diseases, their presence in the blood is determined by antinuclear antibody (ANA) test using indirect immunofluorescence (IF) with HEp2 cells as a substrate. In this work, an immunoperoxidase (IP) assay was developed to evaluate the ANAs in canine sera, using canine kidney cell lines (MDCK) and compared with a commercial immunofluorescence test on Hep2 cells for this system, a fluoresceinated anti-canine Ig antibody was standardized. The study was performed on 50 sera from dogs submitted to the laboratory with different clinical diagnoses of autoimmune-associated diseases. The procedures on both cells were unified to perform comparisons of the reactions, direct sera or at different dilutions were added to a monolayer of permeabilized MDCK cells, followed by a peroxidized anti-canine IgG conjugate, and a substrate for the IP reaction. The same sera were tested on the commercial IF assay on Hep2 cell system. In 22/50 cases, the presence of LE cells in peripheral blood was determined. A high correlation was found in the detection of antinuclear antibodies between both cell lines and techniques, however there were differences in the reaction patterns in the nucleus and cytoplasm between cell lines. The diffuse nuclear pattern observed in MDCK cells was more related to the presence of high percentages of LE cells in peripheral blood. The differences found in the results were possibly associated with the presence of homologous antigens between the MDCK cells and the dog. In addition, the methodology and standardization for the use and interpretation of a reference serum was developed to unify the interpretation criteria in the laboratory.

微载体规模化培养MDCK细胞增殖H9N2亚型禽流感病毒的研究

目的探索H9N2亚型禽流感病毒株(A/Chiken/NX/9/99)在微载体大规模培养的MDCK细胞中的增殖规律,确定最佳增殖条件。方法将H9N2亚型禽流感病毒株接种到生长在24孔培养板上的MDCK细胞中进行增殖试验,检测接种不同感染剂量病毒、添加不同浓度TPCK-胰酶、在不同pH值的培养液中培养,接毒后不同时间的病毒血凝素滴度(HA)。根据最佳增殖条件将病毒接种至生长在微载体上的MDCK细胞中,利用250 mL和5L转瓶逐级进行大规模增殖。结果最佳病毒增殖条件为TPCK-胰酶终浓度为10μg/mL,接毒剂量为MOI=0.025,培养液pH值为7.4,在此条件下,H9N2亚型禽流感病毒株(A/Chiken/NX/9/99)适应在250 mL和5L转瓶中微载体培养的MDCK细胞内大量增殖,病毒的最高血凝价均可达到9log2(1∶512)。结论本研究为以哺乳动物细胞为基质规模化生产禽流感疫苗奠定了基础。

重组H5N3禽流感疫苗株在MDCK细胞中大规模增殖条件研究

为研究通过反义遗传学技术构建的重组禽流感病毒rH5N3疫苗株在MDCK细胞中大规模增殖规律,确定最佳增殖条件,将rH5N3疫苗株分别在500mL和10L转瓶培养的MDCK细胞中进行增殖试验,检测不同接毒量以及接毒后不同时间里的血凝价,以确定病毒的增殖情况。结果表明,在确定的最佳病毒增殖条件下,该重组rH5N3疫苗株在500mL转瓶和10L转瓶中可获得大量增殖,病毒的最高血凝价均可达到1∶1024。rH5N3疫苗株可以在MDCK细胞中大规模增殖,操作方法简便,成本低廉,该方法为禽流感细胞培养型疫苗的大规模生产奠定了基础。

重组禽流感病毒H5亚型Re-7株在MDCK细胞上增殖条件的研究

为了探索重组禽流感病毒H5亚型Re-7株在MDCK细胞上的增值规律,确定最适的接毒量与最佳收获时间。将重组禽流感病毒H5亚型Re-7株接种至100 L生物反应器全悬浮无血清培养的MDCK细胞进行增殖试验,检测不同病毒感染量,接种后不同时间病毒的HA、TCID50以及EID50。根据确定的最佳增值条件将病毒接种到MDCK细胞中进行大规模增殖培养。确定最适接毒量MOI为10^(-2),最佳收获时间为60 h。在100 L生物反应器中进行重复验证,获得稳定的试验结果,病毒HA达到1∶1024,每1 m L病毒含量达到107.33TCID50,每0.1 m L病毒含量达到106.83EID50。研究为重组禽流感病毒H5亚型Re-7株的全悬浮规模化生产提供了相对稳定的参数指标。

H5N1亚型禽流感病毒在MDCK细胞中增殖条件的研究

目的:探索H5N1亚型禽流感病毒在MDCK中增殖规律,确定最佳增殖条件。方法将H5N1亚型禽流感病毒接种到6孔板培养的MDCK细胞进行增殖试验,检测不同病毒感染量、不同浓度TPCK-胰酶,接毒后不同时间病毒的HA滴度。根据确定的最佳增殖条件将病毒接种到微载体培养的MDCK细胞中进行大规模增殖。结果:最佳病毒增殖条件接毒量MOI为5×10-4、TPCK-胰酶浓度为4μg/mL,在5 L生物反应器中重复验证,获得稳定的试验结果,病毒血凝价最高为8 log2。结论:本研究为禽流感疫苗的生物反应器规模化生产奠定了基础。

MDCK细胞微载体悬浮培养放大工艺研究

MDCK细胞对各种流感病毒具有高度敏感性,广泛应用于流感病毒的分离和疫苗制备。通过探索培养基中促进细胞贴壁的关键组分,并筛选水解物,开发了适合MDCK细胞生长的低血清培养基。发现钙、镁离子是细胞贴壁不可缺少的物质,麦麸水解物可以部分代替培养基中的血清。利用该低血清培养基,经过消化转移将MDCK细胞从5 L反应器放大至25 L反应器,微载体上细胞贴附均匀、生长旺盛,25 L反应器中培养48 h细胞密度可达30.5×105cells/ml。研究结果为工业规模反应器微载体悬浮培养MDCK细胞生产流感病毒奠定了基础。