Immunofluorescent localization of platelet-activating factor (PAF) in the rat

Summary An immunofluorescent staining method for detecting platelet-activating factor (PAF) is described. This method employs a polyclonal anti-PAF rabbit antibody. When rat brain, heart, lung, liver or kidney tissue was stained using this method, the heart, lung and kidney exhibited PAF-specific staining. Analysis of the amount of PAF in different organs, either by immunofluorescence or by bioassay, showed that kidney tissue contains the greatest amount of PAF.     

The regulation of tissue eosinophilia. IV. Purification and properties of eosinophil-directed chemotactic inhibitory factors from complete Freund's adjuvant-treated guinea pigs

Eosinophil-directed chemotactic inhibitory factors (ECIF) from T lymphocytes of complete Freund's adjuvant-treated guinea pigs were recovered in two separate molecular weight (MW) fractions: the one is eluted near bovine serum albumin (MW about 70,000), and in pH range between 7.0 and 7.5 by chromatofocusing column, whereas the other is near cytochrome c (MW 12,500), and in pH range between 5.0 and 5.5. It was, however, found by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoadsorption that the high molecular ECIF is probably an aggregated form of the low molecular ECIF. It was subsequently confirmed that both the ECIF had similar physicochemical properties: sensitive to heating at 56 or 80 degrees C sensitive to enzyme treatment with trypsin and neuraminidase, sensitive in acid but not alkaline condition, and bind to peanut agglutinin-or Limulus polyphemus agglutinin-coupled agarose beads. The inhibitory activity of ECIF was suppressed by previous treatment of eosinophils with D-galactose and sialic acid. ECIF activity was specifically absorbed by eosinophils; the absorption was inhibited by pretreatment of eosinophils with D-galactose and sialic acid. Previous treatment of eosinophils with beta-galactosidase and neuraminidase led the cells not to respond to both ECIF. It was thus suggested that the inhibition by ECIF is receptor-mediating phenomenon, and that ECIF and ECIF receptors on eosinophils contain galactose and sialic acid residues which may play an essential role for the biological activity.