title: Effects of intracellular products of Bacillus subtilis VSG1 and Lactobacillus plantarum VSG3 on cytokine responses in the head kidney macrophages of Labeo rohita.
abstract: The efficiency of intracellular products (ICPs) of the probiotics Bacillus subtilis VSG1 and Lactobacillus plantarum VSG3 in stimulating cytokine responses in the head kidney (HK) macrophages of Labeo rohita was investigated. The HK macrophages were incubated with ICPs and lipopolysaccharide (LPS), and the responses of cytokine genes, namely interleukin-10 (IL-10), IL-1β, IL-12p35, IL-12p40, IL-18, tumour necrosis factor-α (TNF-α), nuclear factor kappa B (NF-κB), cyclo-oxygenase-2 (COX-2), interferon-1 (IFN-1), and IFN-γ were assessed by quantitative real-time PCR (qRT-PCR) at 2, 6, 12, 24, and 48 h post-stimulation (hps). Among the proinflammatory cytokines, a strong increase in the gene expression of IL-1β and TNF-α was displayed mainly at 2-6 hps with ICPs, as compared to that of the positive control (LPS) or the negative control (PBS) (P < 0.05). However, COX-2 and NF-κB showed higher expression at 2 and 24 hps, and 6-24 hps with ICPs, respectively. Antiviral cytokines IFN-1 and IFN-γ displayed strong expressions (P < 0.05) at 6-12 hps, and 12-24 hps with ICPs, respectively. Upregulation of the anti-inflammatory cytokine, IL-10, was recorded at 6-24 hps with ICPs, as compared to that controls. Expressions of cell-mediated immune factor genes (IL-12p35, IL-12p40, and IL-18) were also significantly upregulated at different time points, except 48 hps, in HK macrophages stimulated with ICPs. Furthermore, enhanced cellular (phagocytic activity and nitroblue tetrazolium assay) and humoral (lysozyme) immune parameters in stimulated cells confirmed the induction of the inflammatory response. Therefore, the results of this in vitro study indicate that the ICPs of B. subtilis VSG1 or L. plantarum VSG3 have great potential for stimulating the cytokine responses in fish, and are thereby potential immunostimulants to fish. Further studies could be conducted to explore its suitability as an adjuvant vaccine in aquaculture.
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Sib Sankar
authors.initials: SS
authors.lastname: Giri
authors.affiliation: School of Life Sciences, Jawaharlal Nehru University, New Delhi 110067, India.
authors.forename: Shib Sankar
authors.initials: SS
authors.lastname: Sen
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Cheng
authors.initials: C
authors.lastname: Chi
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Hyoun Joong
authors.initials: HJ
authors.lastname: Kim
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea.
authors.forename: Saekil
authors.initials: S
authors.lastname: Yun
authors.affiliation: Laboratory of Aquatic Biomedicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul 151742, South Korea. Electronic address: parksec@snu.ac.kr.
authors.forename: Se Chang
authors.initials: SC
authors.lastname: Park
authors.affiliation: Dept. of Biotechnology, Periyar Maniammai University, Thanjavur 613403, Tamil Nadu, India. Electronic address: drvsukumar@gmail.com.
authors.forename: V
authors.initials: V
authors.lastname: Sukumaran
mesh_terms: D000276:Adjuvants, Immunologic / Q000008:administration & dosage / Q000494:pharmacology*; D000821:Animal Feed / Q000032:analysis; D000818:Animals; D001412:Bacillus subtilis / Q000737:chemistry; D003530:Cyprinidae / Q000235:genetics* / Q000276:immunology* / Q000378:metabolism; D016207:Cytokines / Q000235:genetics* / Q000378:metabolism; D004032:Diet / Q000662:veterinary; D029941:Fish Proteins / Q000235:genetics* / Q000378:metabolism; D060226:Head Kidney / Q000276:immunology; D048191:Lactiplantibacillus plantarum / Q000737:chemistry; D008264:Macrophages / Q000276:immunology; D019936:Probiotics / Q000008:administration & dosage / Q000494:pharmacology*; D060888:Real-Time Polymerase Chain Reaction / Q000662:veterinary
chemical_list: D000276:Adjuvants, Immunologic; D016207:Cytokines; D029941:Fish Proteins
keywords: Bacillus subtilis VSG1; Cytokine responses; Head kidney macrophages; Intracellular products; Labeo rohita; Lactobacillus plantarum VSG3