猪圆环病毒2型特异性单克隆抗体的制备与鉴定

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174 2U14 

(ORFs):ORF1 and ORF2.To be specific.ORF1 encodes viral replica・ 

tion-related Rep (35000)and Rep’ (1 9000)proteins.Pogranichnyy et aL c7】 

showed that Rep protein might be as- 

sociated with the production of PCV2- 

neutralizing antibodies.ORF2,encod- 

ing viraI capsid proteins with high im- 

munogenicity,is the preferred gene 

for construction of recombinant vac- cinesE ̄.In this study.BALB/c mice were 

immunized using synthetic tandem 

polypeptide of Cap protein epitope of 

PCV2 as the antigen protein to pre- 

pare specific monoclonaI antibody which Iaid solid foundation for fu rther 

investigating the structure and function 

of PCV2 ORF2 epitopes and estab- Iishing specific sensitive detection 

methods to Identif、,and diagnose 

PCV2.associated diseases. 

Materials and Methods 

Cells,detected protein and experi- 

mentaI animals 

Myeloma cells SP2/0.PK-1 5 cells 

and PCV2 whole virus were preserved 

in Key Laboratory of Veterinary Bio- 

Iogicals Engineering and Technology, 

Ministry of Aqriculture;five eight-week- old female BALB/c mice were provided 

by the Experimental AnimaI Center of 

Yangzhou University;prokaryotically 

expressed PCV2 PET32a.-ORF2 pro-- 

tein(expressed in E co11),eukaryoti- 

cally expressed PCV2 ORF1——ORF2 

tandem protein (expressed in High— FiveTM cells1 and Baculovirus VP10 

protein were constructed,expressed 

and preserved in Key Laboratory of 

Veterinary Biologicals Engineering and 

Technology,Ministry of Agriculture. 

Reagents PEG-4000,HAT, HT, DMSO 

(Sigma ChemicaI Co.,Ltd.1:DMEM, 

fetaI calf serum (Gibico Co.,Lld.); 

HRP-labeled goat anti—mouse IgG 

【Vazyme Biotech(Nanjing)Co.,Ltd.】; FITC-labeled goat anti-mouse IgG 

(Wuhan Boster BiotechnoIogy Co., 

Ltd.). Preparation of antigen 

A reported epitope of Cap protein 

of PCV2 was synthesized by Abmart (Shanghai)Co.,Ltd.,with the polypep- tide amino acid sequence of DR- 

Tl DYFQPNNK.Tandem polypeptides of the sequence were used as the anti- 

gen for animalimmunization. Animalimmunization 

Five eight..week--old female BALB/ 

c mice were immunized.Firstly,each 

BALB/c mouse was injected intraperi- 

toneally with 50 ug of antigen that was 

emulsified by equal amount of Fre- 

und s complete adjuvant;after two 

weeks.BALB/c mice were injected in- traperitoneally with equal amount of 

antigen that was emulsified by Fre- 

und’s incomplete adjuvant;after two 

weeks.BALB/c mice were injected jn- traDeritOnea¨V with equaI amount of 

antigen until the serum antibody titer 

reached above 1:1 0 000.Finally.each 

BALB/c mouse was injected hypoder- 

mically with 30 uq of antigen 3 d before 

fusion to strengthen the immunit、,. Screening and subcloning of hy- 

bridoma 

Detection program The experiment 

was conducted by indirect ELISA 

method using the established PCV2 

PET32a-ORF2 recombinant protein as 

antigen.Recombinant protein was di- 

Iuted using carbonate buffer f0.05 

mol/L,pH 9.6)and coated on ELlSA plates.using 1%BSA as blocking so- 

lution.HRP—labeled goat anti-mouse 

IgG as enzyme.—linked secondary anti-- 

body,and TMB one-component chro- 

mogenic agent as substrate. Detection and screening of anti- 

body positive wells After fusion. 

when hybridoma cells covered 1,3 Of 

the area of culture wells,the super- 

natant was screened by indirect ELISA 

method,namely,the supernatant of 

celI culture was detected using E coil- 

expressed PET32a--ORF2 recombi-- 

nant protein and expression products 

0f PET32a empty vector.to screen 

hybridoma cells exhibiting positive re- 

action with E col-expressed PET32a- 

ORF2 recombinant protein and nega- 

tive reaction with expression products Of PET32a empty vector. 

Subcloning of cells in antibody 

positive wells Cells in antibody 

positive wells were subcloned jn ac- 

cordance with the Iimiting dilution method[ ̄. 

Scalable culture and cryopreserva- 

tion of positive monoclonaI cells 

Positive hybridoma cells were trans- 

ferred fr0m 96-welI plates to 24-welI 

plates.and then transferred to 6-welI 

plates after overgrowing,which were 

finally transferred to cell culture flasks for incubation.1ncubated cells were 

cryopreserved in accordance with 

c0nventi0naI methods. 

Preparation of ascites 

Scalable culture of antibody..posi-- 

tive hybridoma cells was conducted. 

Firstly.eight.week.old female BALB,c 

mice were iniected intraperitoneally with 0.5 ml of sterile Iiquid paraffin;af— 

ter one week,each BALB/c mouse 

was injected inlraperitoneally with 5 x 1 0 hybridoma cells:after 1 0 d.ascites 

of mice with extremely enlarged ab- 

dominal circumference were collected 

for titer detection by ELlSA and were preserved at-70 oC. 

1dentification of reactivity and 

specificity of monoclonaI antibody 

Western blot assay using prokary-