Table 1

PCR program"

Fig. 1

Preparation of CPB recombinant protein A. SDS-PAGE analysis of protein expression (M. The standard protein molecular weight, 1. The expression (introduction) of pCold I empty plasmid; 2. The expression (without induction) of CPB recombinant plasmid; 3. The expression (introduction) of CPB recombinant plasmid; 4. The supernatant from the expression (introduction) of CPB recombinant plasmid; 5. The precipitation from the expression (introduction) of CPB recombinant plasmid); B. Identification of purified protein by SDS-PAGE (M. The standard protein molecular weight; 1. The sample after ultrasonic disruption; 2. The solution through Nickel slug; 3, 4. Final protein after elution)"

Fig. 2

Construction of CPB nanobody library A. antibody titer for CPB in serum of immuned alpaca; B. Dilution plates for enrichment detection of CPB nanobody library; C. Dilution plates for abundance detection of CPB nanobody library; D. Amino acid sequence alignment of CPB nanobody library. The same amino acid sequences were in the red boxex"

Fig. 3

Screening and identification of CPB-VHH A. Screening of CPB-VHH phage supernatant, the red dotted line (cut off) represented OD450 nm=0.62; B. Expression optimization of CPB-VHH prokaryotic plasmid (including IPTG concentration, temperature and rotation speed); C. SDS-PAGE identification of purified CPB-VHH with the target band in red box"

Fig. 4

Evaluation of the properties of CPB-VHH A. CPB-VHH stability at different temperatures; B. Half-life of CPB-VHH; C-D. CPB-VHH affinity for CPB"

Fig. 5

Determination of critical value for ELISA method"

Fig. 6

Standard curve of ELISA method"

Fig. 7

Specificity of ELISA method"

Fig. 8

PCR results for CPB detection M. DNA molecular mass standard; 1-8. Sheep feces; 9-16. Chicken serum; 17-21. Alpaca feces; 22-25. Alpaca intestinal contents"