Regulation of macrophage and dendritic cell function by pathogens and through immunomodulation in the avian mucosa

Abstract

Macrophages (MPh) and dendritic cells (DC) are members of the mononuclear phagocyte system. In chickens, markers to distinguish MPh from DC are lacking, but whether MPh and DC can be distinguished in humans and mice is under debate, despite the availability of numerous markers. Mucosal MPh and DC are strategically located to ingest foreign antigens, suggesting they can rapidly respond to invading pathogens. This review addresses our current understanding of DC and MPh function, the receptors expressed by MPh and DC involved in pathogen recognition, and the responses of DC and MPh against respiratory and intestinal pathogens in the chicken. Furthermore, potential opportunities are described to modulate MPh and DC responses to enhance disease resistance, highlighting modulation through nutraceuticals and vaccination.

Keywords: (Draining) lymph nodes; AIV; APC; Ag; BALT; BM; C-type lectin receptors; CG; CLR; DC; DC-SIGN; DC-specific intercellular adhesion molecule-3-grabbing non-integrin; Dendritic cells; GALT; HA; HPAI; IAV; IBDV; IBV; Immunomodulation; Infection; LGP2; LPAI; LPS; MDA5; MGL; MMR; MPh; Macrophages; Mucosal; NA; NALT; NDV; PRR; RIG-I; RT; TLR; antigen; antigen-presenting cells; avian influenza virus; bone marrow; bronchus-associated lymphoid tissue; cLL; chicken galectin; chicken lung lectin; dLN; dendritic cells; gut-associated lymphoid tissue; haemagglutinin; highly-pathogenic avian influenza; infectious bronchitis virus; infectious bursal diease virus; influenza A virus; laboratory of genetics and physiology 2; lipopolysaccharide; low pathogenic influenza; macrophage galactose binding lectin; macrophage mannose receptor; macrophages; melanoma differentiation-associated protein 5; nasal associated lymphoid tissue; neuraminidase; newcastle disease virus; pattern recognition receptors; respiratory tract; retinoic acid-inducible gene I; toll-like receptors.