Role of porcine reproductive and respiratory syndrome virus nucleocapsid protein in induction of interleukin-10 and regulatory T-lymphocytes (Treg).

Porcine reproductive and respiratory syndrome virus (PRRSV) infection induces interleukin (IL)-10 production and increased numbers of PRRSV-specific regulatory T-lymphocytes in infected pigs. In the present study, the roles of the nucleocapsid (N) protein in induction of IL-10 and CD4(+)CD25(+)Foxp3(+) lymphocytes (T(reg)) were investigated. Transfection of porcine monocyte-derived dendritic cells (MoDCs) and pulmonary alveolar macrophages (PAMs) with a plasmid encoding N protein resulted in significant upregulation of IL-10 gene expression in the gene-transfected cells. Structural conformation, but not nuclear localization, of the expressed N protein was indicated to be essential for the ability to induce IL-10. Furthermore, the presence of recombinant N proteins in cultured PBMCs increased the number of IL-10-producing lymphocytes. Strong induction of IL-10-producing cells and T(reg) was observed when using N protein-pulsed MoDCs, suggesting an important role of MoDCs in induction of IL-10 and T(reg) by the N protein. Neutralization of IL-10 by addition of an anti-IL-10 antibody in the culture system resulted in marked reduction of PRRSV-induced T(reg) in the cultured PBMCs. Together, the data demonstrate the immunomodulatory properties of the PRRSV N protein and the linkage between IL-10 production and development of PRRSV-induced T(reg). Our results reveal an immunomodulatory function of the PRRSV N protein that may contribute to the unique immunological outcome observed following PRRSV infection.

Tissue engineering of cartilage with porous polycarprolactone--alginate scaffold: the first report of tissue engineering in Thailand.

OBJECTIVE: To engineer human cartilage with porous polycaprolactone (PCL)-Alginate Scaffold. BACKGROUND: Polycaprolactone (PCL) is a prolonged degradable polymer that has good mechanical strength. The authors fabricated PCL as an ear shaped scaffold. Alginate hydrogel was used to seed chondrocyte into the PCL porous scaffold by a gel-cell seeding technique. MATERIAL AND METHOD: PCL Scaffolds were fabricated like human pinna by particle leaching technique. Chondrocyte was isolated from human rib cartilage and then cultured. The cultured chondrocyte were mixed with 1.2% alginate and b-FGF (basic-fibroblast growth factor) 5 ng/ml at a concentration of 25 x 10(6) cell/ml, then were seeded in porous PCL scaffold to make the constructs. The constructs were cultured in vitro for 1 week. Then they were implanted in subcutaneous plane of the back of six-female nude mice (5 weeks old). Two nude mice were sacrificed at 2, 3, and 6 months. Histological study was done (H&E, Alcian blue, collagen type II). RESULT: Neocartilage was formed in the porous cavity of PCL scaffold. At 2 and 3 months, neocartilage were similar to very young cartilage. At 6 months, they were mature. The delayed maturation until 6 months and the highly vascularization of neocartilage in the early phase was the effect of human b-FGF The growths of neocartilage islands in porous cavity were also observed along with degradation ofPCL inter-porous septum. CONCLUSION: This paper reports the first success of cartilage tissue engineering in Thailand.