Modulation of the chemotactic responsiveness of guinea pig neutrophils to hrIL-8 and fMLP.
Neutrophils elicited in the peritoneal cavity of guinea pigs were purified on Percoll gradients and their chemotactic response to hrIL-8 and fMLP measured in vitro. hrIL-8 and fMLP were effective chemoattractants with optimal concentrations of 6 x 10(-9) and 1 x 10(-7) M, respectively. Scatchard analysis revealed approximately 205,000 IL-8 receptors/cell and 34,000 fMLP receptors/cell with KD values of 4.1 x 10(-9) and 3.3 x 10(-8) M, respectively. At suboptimal concentrations of chemoattractants the response was inhibited by dibutyryl cyclic AMP, histamine, and adenosine in the presence of a phosphodiesterase inhibitor. IL-8 and fMLP induced an increase in cellular cyclic AMP and the response to optimal concentrations of chemoattractants was inhibited by Calphostin C and Ro 31-8220, inhibitors of protein kinase C (PKC). Our results indicate that the chemoattractants activate the same PKC-dependent pathway that is down-regulated by cyclic AMP-dependent mechanisms.
Dai
Y
Y
Immunopharmacology Group, Southampton General Hospital, United Kingdom.
Holgate
S T
ST
Church
M K
MK
Shute
J K
JK
D000595:Amino Acid Sequence; D000818:Animals; D002630:Chemotactic Factors / Q000494:pharmacology*; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D000242:Cyclic AMP / Q000096:biosynthesis / Q000378:metabolism / Q000502:physiology; D006168:Guinea Pigs; D016209:Interleukin-8 / Q000494:pharmacology*; D007700:Kinetics; D008297:Male; D008969:Molecular Sequence Data; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology*; D009504:Neutrophils / Q000166:cytology* / Q000187:drug effects*; D011493:Protein Kinase C / Q000037:antagonists & inhibitors / Q000378:metabolism; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic / Q000378:metabolism; D018123:Receptors, Interleukin / Q000378:metabolism; D018000:Receptors, Peptide / Q000378:metabolism; D011994:Recombinant Proteins / Q000494:pharmacology
D002630:Chemotactic Factors; D016209:Interleukin-8; D044042:Receptors, Formyl Peptide; D011971:Receptors, Immunologic; D018123:Receptors, Interleukin; D018000:Receptors, Peptide; D011994:Recombinant Proteins; D009240:N-Formylmethionine Leucyl-Phenylalanine; D000242:Cyclic AMP; D011493:Protein Kinase C