Abstract
Background/Aim:Recent studies have shown that interleukin-15 (IL-15)is a critical factor for the development and proliferation of CD8+ memory T cells. The aim of present study is to study the role bovine IL-15 (bIL-15)in activation pathway of bovine CD8+ T cells if any, which will be useful in designing the adjuvant to increase the duration of immunity of the vaccine preparations.Materials and Methods:Coding region of bIL-15 (489) was amplified from cDNA of lipopolysaccharide-induced bovine peripheral blood mononuclear cells (PBMCs) using gene specific primers and cloned into pcDNA3.1+. Mature length of bIL-15 was amplified using gene specific primers and cloned into pET32a for expression studies. Expressed fusion protein was purified using Ni-Nitrilotriacetic acid agarose affinity chromatography and analyzed by SDS-Polyacryamide gel electrophoresis (PAGE) and western blotting. Biological activity of purified protein was analyzed by quantitative Polymerase Chain Reaction (qPCR) for an increase in levels of Bcl2, STAT3 and STAT5a using cDNA synthesized from RNA of PBMCs induced with different concentrations of purified bIL-15. Role of IL-15 in inducing memory CD8+ T cells was analyzed by qPCR for increase in the level of Carnitine Palmitoyl Transferase 1a (CPT1a) using cDNA synthesized from RNA of PBMCs induced with different concentrations of purified bIL-15.Results:Bovine IL-15 was amplified and analyzed by agarose gel electrophoresis, which showed a specific product of ~490bp, mature sequence was amplified using full-length as a template to get a product of ~350bp. The protein was expressed, purified and analyzed by SDS-PAGE and Western blotting, which showed a specific product of 32kDa. Biological activity of purified bIL-15 fusion protein showed an increase in levels of Bcl2, STAT3 and STAT5a with 5 fold, 9 fold, and 10 fold increases as analyzed by qPCR, respectively. Role of IL-15 in inducing memory T cells showed an increase in expression level of CPT1a at 2.5 fold increase as compared to control cells.Conclusion:Bovine IL-15 has been successfully cloned and expressed in our work, and the biological activity shows that the purified fusion protein is biologically active. As there is an increase in levels of CPT1a an enzyme critical for survival of memory T cells, IL-15 can be used for increase in the memory response, which can be used as an adjuvant with viral vaccines for increasing the immunity.
Highlights
Interleukin (IL-15), a critical factor for the development, proliferation and activation of effector, natural killer and CD8+ memory T cells, was first identified based on its ability to stimulate the IL-2 dependent CTLL-2 T cell lines in the presence of neutralizing IL-2 antibodies [1]
Biological activity of purified bovine IL-15 (bIL-15) fusion protein showed an increase in levels of Bcl2, STAT3 and STAT5a with 5 fold, 9 fold, and 10 fold increases as analyzed by quantitative Polymerase Chain Reaction (qPCR), respectively
As there is an increase in levels of Carnitine Palmitoyl Transferase 1a (CPT1a) an enzyme critical for survival of memory T cells, IL-15 can be used for increase in the memory response, which can be used as an adjuvant with viral vaccines for increasing the immunity
Summary
Interleukin (IL-15), a critical factor for the development, proliferation and activation of effector, natural killer and CD8+ memory T cells, was first identified based on its ability to stimulate the IL-2 dependent CTLL-2 T cell lines in the presence of neutralizing IL-2 antibodies [1]. Mature IL-15 is a glycoprotein of 14-15 kDa in length with 2 inter disulfide bonds, carries out its signal transduction by reacting with specific receptors IL-15 Rαβγ, where in it shares a common receptor βγc with IL-2 and Rα is specific for IL-15 As it shares a common receptor of IL-2 (IL-2 βγc), it delivers its action through the activation of Jak/STAT pathway similar to IL-2 [2,3]. Switch of metabolism has been clearly shown during the activation of the naïve T cells [7,8,9] With these reports, it is clear that the switch of metabolism between naïve, effector and memory cells from oxidative phosphorylation to glycolysis and back to oxidative phosphorylation is a major process to decide
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
