Submitted to: PLoS One
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 5/15/2013
Publication Date: 11/24/2013
Citation: Jeong, J., Kim, W.H., Yoo, J., Lee, C., Kim, S., Cho, J., Jang, H., Kim, D.W., Lillehoj, H.S., Min, W. 2013. Identification and comparative expression analysis of interleukin 2/15 receptor B chain in chickens infected with E. tenella. PLoS One. 7(5):e37704. doi: 10.1371/journal.pone.0037704. Interpretive Summary: Cell-mediated immune response against intracellular parasites involves cell associated receptor recognition system which signals other cells to initiate adaptive immunity. In chickens, lymphocyte-secreted interleukin 2 (IL2) and IL15 play key roles in the regulation T cells and natural killer (NK) cells in defense against coccidiosis. The effects of these cytokines on target cells are mediated by their heterotrimeric receptors that consist of a specific alpha-subunit and two shared subunits, IL2 and IL15 receptor beta (IL2/15Receptor beta, CD122) and a common cytokine receptor gamma. In this paper, an ARS scientist collaborated with scientists at a Korean university to demonstrate for the first time the existence of chicken IL2/15Receptor beta (chIL2/15Receptor beta). The full sequence of chIL2/15Receptor beta gene has been deciphered and its function in coccidiosis has been studied. Furthermore, quantitative real-time PCR was used to evaluate expression profiles of chIL2/15Receptor beta and related cytokines and receptors in ConA-stimulated splenic lymphocytes and ceca-tonsils and spleens from chickens infected with E. tenella. This new information will enhance our understanding of poultry immunity against coccidiosis and may facilitate the development of effective immune strategies to reduce coccidiosis.
Technical Abstract: Background: Interleukin (IL) 2 and IL15 receptor beta chain (IL2/15Receptor beta, CD122) play critical roles in signal transduction for the biological activities of IL2 and IL15. Increased knowledge of non-mammalian IL2/15Receptor beta will enhance the understanding of IL2 and IL15 functions. Methology/Principal Findings: Chicken IL2/15Receptor beta (chIL2/15Receptor beta) cDNA was cloned using 5'/3'-RACE. The predicted protein sequence contained 576 amino acids and typical features of the type-I cytokine receptor family. COS-7 cells transfected with chIL2/15Receptor beta produced proteins of approximately 75 and 62.5 kDa under normal and tunicamycin-treated conditions, respectively. The genomic structure of chIL2/15Receptor beta was similar to its mammalian counterparts. chIL2/15Receptor beta transcripts were detected in the lymphoblast cell line CU205 and in normal lymphoid organs and at low levels in bursa samples. Expression profiles of chIL2/15Receptor beta and its related cytokines and receptors were examined in ConA-stimulated splenic lymphocytes and in ceca-tonsils of Eimeria tenella-infected chickens using quantitative real-time PCR. Expression levels of chIL2/15Receptor beta, chIL2Receptor alpha, and chIL15Receptor alpha were generally elevated in ceca-tonsils and ConA-activated splenic lymphocytes. However, chIL2 and chIL15 expression levels were differentially regulated between the samples. chIL2 expression was upregulated in ConA-activated splenic lymphocytes, but not in ceca-tonsils. In constrast, chIL15 expression was upregulated in ceca-tonsils, but not in ConA-activated splenic lymphocytes. Conclusions/Significance: We identified an avain form of IL2/15Receptor beta and compared its gene expression pattern with those of chIL2, chIL15, chIL2Receptor alpha, and chIL15Receptor alpha. Findings suggest that chIL15 and its receptors, including chIL2/15Receptor beta, play important roles in mucosal immunity to intestinal intracellular parasites such as Eimeria.