Differential regulation of cytokine gene expression by avian heterophils during receptor-mediated phagocytosis of opsonized and nonopsonized Salmonella enteritidis.
Internalization of pathogens by phagocytic cells triggers the innate immune response, which in turn regulates the acquired response. Phagocytes express a variety of receptors that are involved in recognition of pathogens, including (1) pattern recognition receptors (PRR), which recognize conserved motifs, (2) complement receptors (CR), which recognize complement-opsonized pathogens, and (3) Fc receptors (FcR), which recognize antibody-opsonized pathogens. Recognition of microbes is accompanied by the induction of multiple cell processes, including the production of proinflammatory and anti-inflammatory cytokines and chemokines. The objective of the present experiments was to use probes to known avian proinflammatory and anti-inflammatory cytokines and TaqMan technology to ascertain levels of cytokine gene expression in avian heterophils following receptor-mediated phagocytosis of either nonopsonized Salmonella enteritidis (SE), serum-opsonized SE, or IgG-opsonized SE. Expression of interleukin-6 (IL-6) and IL-8, considered in mammals as a proinflammatory chemokine, were upregulated following exposure to the nonopsonized or the opsonized SE. However, mRNA expression for IL-18 and interferon-gamma (IFN-gamma) was downregulated, and the expression of mRNA for the anti-inflammatory cytokine transforming growth factor-beta4 (TGF-beta 4) was upregulated. Interestingly, IL-1beta mRNA expression was significantly upregulated in heterophils that phagocytized either the nonopsonized SE via PRRs or IgG-opsonized SE via FcRs, whereas serum-opsonized SE phagocytized by CRs induced a downregulation of IL-1beta mRNA. These results suggest that signaling interactions initiated by receptor recognition of the microbe surface differentially regulate the induction of inflammatory cytokines in avian heterophils.
Kogut
Michael H
MH
USDA-ARS, SPARC, College Station, TX 77845, USA. kogut@ffsru.tamu.edu
Rothwell
Lisa
L
Kaiser
Pete
P
D000818:Animals; D001483:Base Sequence; D002645:Chickens / Q000276:immunology* / Q000382:microbiology; D016207:Cytokines / Q000032:analysis / Q000096:biosynthesis* / Q000235:genetics; D005786:Gene Expression Regulation; D008969:Molecular Sequence Data; D009504:Neutrophils / Q000276:immunology* / Q000382:microbiology; D009895:Opsonin Proteins / Q000378:metabolism*; D010587:Phagocytosis; D011956:Receptors, Cell Surface / Q000378:metabolism*; D011951:Receptors, Complement / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D012477:Salmonella enteritidis / Q000276:immunology*; D018417:Th1 Cells / Q000276:immunology / Q000382:microbiology; D018418:Th2 Cells / Q000276:immunology / Q000382:microbiology
D016207:Cytokines; D009895:Opsonin Proteins; D011956:Receptors, Cell Surface; D011951:Receptors, Complement