Characterization of host responses induced by Toll-like receptor ligands in chicken cecal tonsil cells

• Published in: Veterinary immunology and immunopathology Vol. 174; pp. 19 - 25
• Main Authors: Taha-abdelaziz, Khaled, Alkie, Tamiru Negash, Hodgins, Douglas C., Shojadoost, Bahram, Sharif, Shayan
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier B.V 01.06.2016
• Subjects: Animals; Antimicrobial Cationic Peptides - genetics; Avian Proteins - immunology; bursa of Fabricius; cathelicidins; Cecal tonsils; Cecum - cytology; Cecum - immunology; Chicken; chickens; Chickens - anatomy & histology; Chickens - genetics; Chickens - immunology; Cytokines; Cytokines - genetics; Gene Expression; Host-Parasite Interactions - immunology; Immunity, Mucosal; In Vitro Techniques; Innate responses; interferon-gamma; interleukin-13; interleukin-1beta; interleukin-6; intestines; Ligands; lipopolysaccharides; Lymphoid Tissue - cytology; Lymphoid Tissue - immunology; mammals; microorganisms; oligodeoxyribonucleotides; Oligodeoxyribonucleotides - immunology; pathogens; spleen; Th1 Cells - immunology; Th2 Cells - immunology; Toll-like receptor; Toll-like receptor 2; Toll-like receptor 4; Toll-Like Receptors - immunology; tonsils; vaccine adjuvants; Ligands; Chicken; Cytokines; Innate responses; Toll-like receptor; Cecal tonsils
• ISSN: 0165-2427; 1873-2534; 1873-2534
• DOI: 10.1016/j.vetimm.2016.04.002

•TLR ligands elicit innate responses in cecal tonsil mononuclear cells.•CpG ODN elicits higher responses in comparison to LPS or Pam3CSK4.•The use of TLR ligands as mucosal adjuvants is proposed. The innate responses of cecal tonsils against invading microorganisms are mediated by conserved pattern recognition receptors (PRRs) such as the Toll-like receptors (TLRs). TLRs expressed by mammalian and avian immune system cells have the capability to recognize pathogen-associated molecular patterns (PAMPs). Although, the role of TLR ligands in innate and adaptive responses in chickens has been characterized in spleen and bursa of Fabricius, considerably less is known about responses in cecal tonsils. The aim of the current study was to assess responses of mononuclear cells from cecal tonsils to treatment with the TLR2, TLR4 and TLR21 ligands, Pam3CSK4, lipopolysaccharide (LPS), and CpG oligodeoxynucleotide (ODN), respectively. All three ligands induced significant up-regulation of interferon (IFN)-γ, interleukin (IL)-1β, IL-6 and CxCLi2/IL-8, whereas no significant changes were observed in expression of IL-13 or the antimicrobial peptides, avian β-defensin (AvBD) 1, AvBD2 and cathelicidin 3 (CATHL-3). In general, CpG ODN elicited the highest cytokine responses by cecal tonsil mononuclear cells, inducing significantly higher expression compared to LPS and Pam3CSK4, for IFNγ, IL-1β, IL-6 and CxCLi2 at various time points. These findings suggest the potential use of TLR21 ligands as mucosal vaccine adjuvants, especially in the context of pathogens of the intestinal tract.