Fig. 1

Identification of recombinant plasmid pET-28a-IL-15 and expression of IL-15 A. Identification of recombinant plasmid pET28a-IL-15 by PCR and enzyme digestion (M. 5 000 bp DNA ladder; 1, 2 and 5. PCR products of empty plasmid pET28a (+), recombinant plasmid pET28a-IL-15 and porcine lymphoid tissue, respectively; 3 and 4. EcoR Ⅰ-Xho Ⅰ double digest products of pET28a-IL-15 and pET28a (+), respectively); B. SDS-PAGE analysis (M. 10-250 ku protein molecular weight standards; 1 and 2. IL-15 protein-expressing bacteria before and after induction, respectively); C. Western blot identification (M. 8-180 ku protein molecular weight standards; 1. E. coli transferred by the empty plasmid pET-28a (+); 2. Expressed IL-15)"

Fig. 2

Identification of recombinant expression plasmid pcDNA3.1-IL-15 and expression of IL-15 in PK-15 A. Identification of recombinant expression plasmids (M. 5 000 bp DNA ladder; 1 and 2. PCR identification of the blank plasmid and recombinant expression plasmids, respectively; 3 and 4. EcoRⅠ-Xho Ⅰ double digestion of recombinant expression plasmids and the blank plasmids, respectively); B. Western blot identification (M. 8-180 ku protein molecular weight standards; 1 and 2. Results of the reaction of PK-15 cells transfected with recombinant expression plasmids with IL-15 antibody-negative serum and IL-15 antiserum, respectively; 3. Results of the reaction of cells transfected with the blank plasmids with IL-15 antiserum); C. IFA identification."

Fig. 3

Identification of monoclonal antibodies by Western blot M. 10-250 ku protein molecular weight standard; 1-9. Monoclonal antibodies (1E8, 1F4, 2D3, 2C10, 2F3, 2D10, 3F4, 3D4, and D5); 10. Anti-IL-15 mouse serum; 11. Anti-IL-15 negative mouse serum; 12. SP2/0 cell supernatant"

Fig. 4

Indirect immunofluorescence identification of monoclonal antibodies A-D. Monoclonal antibodies 2C10, 2D10, 2F3 and 3D5; E and F. Anti-IL-15 positive and negative mouse serum"

Fig. 5

Detection of monoclonal antibody specificity"

Fig. 6

Determination of antibody working concentration and the blocking buffer A, B and C. Determination of the coating concentration of capturing antibody, the blocking buffer, and the dilution ratio of HRP-2C10, respectively"

Fig. 7

The linear range of the standard curve and the sensitivity of sandwich ELISA A. Sstandard curve. B. Sensitivity analysis"

Fig. 8

Specificity detection of the sandwich ELISA"

Table 1

Application of IL-15 sandwich ELISA ng·mL-1"

Fig. 9

Western blot detection and gray value analysis of IL-15 expression in DC A. Western blot; B. Gray value analysis of reaction bands (1-16. DC isolated from different porcine lymph nodes)"