Human lymphocyte function-associated antigen 3 (hLFA3) has been identified as an important T cell accessory molecule. Rhesus monkeys (Macaca mulatta) have been widely used as animal models for human immune disorders. Due to the species-specificity of immune system, it is necessary to study M. mulatta LFA3 (mmLFA3). In this study, the gene encoding mmLFA3 CD2-binding domain (mmLFA3Sh) was amplified by polymerase chain reaction (PCR) and genetically fused to human IgG1 Fc fragment in pPIC9K to construct the expression plasmid pPIC9K-mmLFA3Sh-Ig. Approximately 3-4 mg mmLFA3Sh-Ig protein was recovered from 1 L of inductive media, and mmLFA3Sh-Ig produced by the P. pastoris can bind to the CD2 positive cells, and suppress the monkey and human lymphocytes proliferation induced by Con A and alloantigen in a dose-dependent manner. These results suggested that mmLFA3Sh-Ig might be used as a novel tool for pathogenesis and experimental immunotherapy of Rhesus monkey immune disorders.
Human tumor necrosis factor-related apoptosis-inducing ligand (hTRAIL) might be developed as a novel anti-tumor drug due to its selective cytotoxicity in tumor cells. The predicted Macaca mulatta TRAIL (mmTRAIL) is highly homologous to hTRAIL in nucleotide acid as well as amino acid sequence, suggesting that mmTRAIL might induce apoptosis of human cancer cells. However, the cytotoxicity of mmTRAIL in human cancer cells has not been investigated. In this paper, it is reported that the gene encoding mmTRAIL has been cloned by using reverse-transcriptase polymerase chain reaction (RT-PCR) from monkey peripheral blood mononuclear cells (PBMCs) in our laboratory. Subsequently, an expression plasmid was constructed by inserting mmTRAIL gene into pQE30 plasmid. After induction by addition of Isopropylβ-D-1-Thiogalactopyranoside (IPTG), mmTRAIL was expressed. MmTRAIL was recovered from supernatant of sonicated bacteria by Ni-NTA agarose affinity chromatography. SDS-PAGE and gel filtration chromatography demonstrated that mmTRAIL forms trimer in solution. In vitro assays indicated that mmTRAIL was cytotoxic to human COLO205 tumor cells but not to normal cells at low concentration of nanomole. In addition, antitumor effect of mmTRAIL was evaluated in mice bearing human COLO205 tumor xenografts. Intratumorally injected mmTRAIL significantly inhibited growth of tumor grafts. These results suggested that mmTRAIL was valuable as candidate drug for cancer-targeted therapy.