The purified antibody (diluted 1:100 in TBS) was applied at 4C overnight

The purified antibody (diluted 1:100 in TBS) was applied at 4C overnight. were generated by immunizing SD rats at five sites with 200?g recombinant human CXCL4 (rhCXCL4) in Freund’s complete adjuvant at the ratio (1:1). Reimmunization was accomplished using the same protocol but with the antigen in Freund’s incomplete adjuvant once a week for 3 weeks. Testing bleed was performed until serum became positive to the antigen in enzyme-linked immunosorbent assays (ELISAs) against rhCXCL4. Three days after the last injection of the antigen, lymphocytes were isolated from the spleen of CD40 the immunized rat and fused with the mouse myeloma cell line SP2/0 in tissue culture. Several hybridoma clones were isolated and established with ELISA against both human and mouse recombinant CXCL4 (4?g/well). The positive clones were subcloned at least three times using the limiting dilution method. Furthermore, we excluded the His-tag provoked immunogenicity by re-screening the clones that were not recognizing recombinant mouse CXCL14 protein (rmCXCL14) with His-tag. rmCXCL4 also shares 39% amino acid identity with rmCXCL14, which provided additional high specificity to the positive clones. We calculated the ratio of the absorbance of samples and the negative control (P/N), and chose the P/N value of 2 for our cutoff base line. Antibody production To produce ascitic fluid, hybridoma cells were injected into the peritoneum of paraffin liquid-primed nude mice. Ascitic fluid was then drained from AF-DX 384 the peritoneum by using an 18-gauge needle, and the monoclonal antibody (MAb) was purified by protein G affinity chromatography (HiTrap protein G HPcolumn, GE Healthcare, Buckinghamshire, United Kingdom). The MAb concentration was detected according to BCA kit (Beyotime Biotechnology, Haimen, China). The properties of the antibody were analyzed by sodium dodecylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE) and stained with Coomassie brilliant blue. Western blot analysis rhCXCL4 and rmCXCL4 was loaded in equal amounts and separated by SDS-PAGE, followed by immunoblotting with MAb produced by hybridoma clones for CXCL4. Briefly, samples were mixed with Laemmli buffer, boiled at 95C for 10?min and loaded onto SDS-PAGE. Proteins were separated by electrophoresis and blotted onto nitrocellulose (Pierce, Rockford, IL). Non-specific binding was reduced by blocking the membrane in 5% non-fat dry milk. The purified antibody (diluted 1:100 in TBS) was applied at 4C overnight. After washing, the membranes were incubated in peroxidase-coupled goat anti-rat IgG (Beyotime Biotechnology) and were diluted 1:1000 in 5% non-fat dry milk for 1?h at AF-DX 384 room temperature. After four washes, enhanced chemiluminescence (ECL, Pierce) was applied to the membranes, which were then exposed to an X-ray film (Kodak, Rochester, NY). Amplification of VL and VH gene fragments and nucleotide sequencing The total RNA was extracted from 107 cells AF-DX 384 of hybridoma 16D6-3 with TRIzol reagent (Invitrogen, Carlsbad, CA) and retro-transcripted into cDNA with a retro-transcriptase kit (Toyobo, Osaka, Japan) according to the manufacturer’s protocol. The resulting cDNA was split into six tubes (3 for VH and 3 for VL PCR) in equal amount and subjected to amplification: one step of denaturation (95C, 5?min), 30 cycles (95C, 30?s; 60C, 30?s; 72C, 30?s), and a finishing step (72C, 10?min). PCR reactions were performed by ExTaq DNA polymerase (Takara Biotechnology, Dalian, China) using the AF-DX 384 degenerated primers at a concentration of 1 1?M each. AF-DX 384 All forward primers were used separately with a mix of the corresponding backward primers as described previously.(24) The amplified VH and VL genes were cloned into pMD19-T Vectors (Takara Biotechnology), and sequenced using M13 primers (Jie Li Bio.,.