Prokaryotic expression of woodchuck cytotoxic T lymphocyte antigen 4 (wCTLA-4) and preparation of polyclonal antibody to wCTLA-4

Preparation and characterization of polyclonal antibody against Kaposi's sarcoma-associated herpesvirus lytic gene encoding RTA

Replication and transcription activator (RTA) is a critical lytic protein encoded by Kaposi's sarcoma-associated herpesvirus (KSHV). To prepare rabbit polyclonal antibody against RTA, three antigenic polypeptides of KSHV RTA were initially synthesized. The fragment of RTA was cloned into p3FlagBsd to construct the recombinant plasmid, pRTA-Flag. 293 T and EA.hy926 cells were transfected with pRTA-Flag to obtain RTA-Flag fusion protein, which was detected using anti-Flag antibody. Next, New Zealand white rabbits were immunized with keyhole limpet hemocyanin-conjugated peptides to generate polyclonal antibodies against RTA. Enzyme-linked immunosorbent assays were performed to characterize the polyclonal antibodies, and the titers of the polyclonal antibodies against RTA were greater than 1:11,000. Western blotting and immunofluorescence assay revealed that the prepared antibody reacted specifically with the RTA-Flag fusion protein as well as the native viral protein in KSHV-infected primary effusion lymphoma cells. Collectively, our work successfully constructed the recombinant expression vector, pRTA-Flag, and prepared the polyclonal antibody against RTA, which was valuable for investigating the biochemical and biological functions of the critical KSHV lytic gene.

Molecular characterization of woodchuck CD4 (wCD4) and production of a depletion monoclonal antibody against wCD4

CD4 T cells play an important role in the immune response against hepatitis B virus (HBV) infection. Woodchucks represent an excellent animal model to study HBV infection. In this study, we characterized the cDNA sequence of woodchuck CD4 (wCD4). The deduced wCD4 protein has four extracellular immunoglobulin-like domains comparable to the other mammalian CD4 molecules. The important extracellular cysteine residues and the intracellular tyrosine protein kinase-binding site of wCD4 are also conserved. The deduced wCD4 protein shows 53-63% identity with the counterparts of other mammalians. Phylogenetic analysis indicates that wCD4 is closely related with the counterparts of primates. Two polyclonal antibodies (pAbs) and four monoclonal Abs (mAbs) against wCD4 were produced. Two pAbs and one mAbs (G2) were found to effectively suppress ConA induced proliferation in vitro. Anti-wCD4 mAb G2 depleted 60% of CD4 cells from healthy woodchucks, while the remaining CD4 cells responded well to ConA stimulation. This work provides a basis for studying CD4 T cell mediated immune responses against HBV infection in the woodchuck model.

Preparation and application of polyclonal antibodiesagainst KSHV v-cyclin

We prepared rabbit polyclonal antibodies against Kaposi's sarcoma-associated herpesvirus (KSHV)-encoded v-cyclin (ORF 72) and detected the natural viral protein using these polyclonal antibodies. Three antigenic polypeptides of v-cyclin were designed and synthesized. A fragment of the v-cyclin gene was cloned into a eukaryotic expression vector pEF-MCS-Flag-IRES/Puro to construct a recombinant vector, pEF v-cyclin. Then, pEF v-cyclin was transfected into 293T and EA.hy926 cells to obtain v-cyclin-Flag fusion proteins. Six New Zealand white rabbits were immunized with KLH-conjugated peptides to generate polyclonal antibodies against v-cyclin. The polyclonal antibodies were then characterized by ELISA and Western blotting assays. Finally, the polyclonal antibodies against v-cyclin were used to detect natural viral protein expressed in BCBL-1, BC-3, and JSC-1 cells. The results showed that using the Flag antibody, v-cyclin-Flag fusion protein was detected in 293T and EA.hy926 cells transfected with pEF-v-cyclin. Furthermore, ELISA showed that the titer of the induced polyclonal rabbit anti-v-cyclin antibodies was higher than 1:8,000. In Western blotting assays, the antibodies reacted specifically with the v-cyclin-Flag fusion protein as well as the natural viral protein. The recombinant expression vector pEF-v-cyclin was constructed successfully, and the polyclonal antibodies prepared can be used for various biological tests including ELISA and Western blotting assays.

Expression and purification of human ARP1 protein and rapid preparation of polyclonal antibody

Angiopoietin-related protein 1 (ARP1) is one of the antiangiogenic factors and plays an important role in endothelial cell proliferation, migration, and blood vessel network formation. Here a rapid method to prepare ARP1 polyclonal antibody in 1 month was developed. The gene of fibrinogen homology domain (FD) for ARP1 was cloned and the protein was expressed in a soluble form of MBP-FD fused protein. The MBP-FD protein was purified using amylose affinity chromatography of maltose-binding protein. Polyclonal antibodies against MBP-FD were obtained through immunization in BALB/c mice. The titer was determined by indirect enzyme-linked immunosorbent assay (ELISA), and the antibody specificity was assessed by Western blot. The full-length ARP1 protein in stable form expressed in transfected human large lung cancer cell lines NCI-H460 was detected by immunocytochemistry (ICC) analysis using ARP1 polyclonal antibodies. The result shows that the antibody possesses good specificity and sensitivity. This work provides a substantial base for the further studies of ARP1 function and associated mechanisms. Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file.