The opsonising activity of a pentraxin-like protein isolated from snapper (Pagrus auratus, Sparidae) serum.
In mammals the pentraxins, C-reactive protein (CRP) and serum amyloid P component (SAP) are important components of the immune response. Although pentraxins have been isolated from a number of fish species few studies detail their functional immunological role. In this paper we report the establishment of a flow cytometry based assay to measure the phagocytic activity of isolated snapper head kidney leukocytes (HKLs). This assay was then used to examine the ability of a pentraxin-like protein isolated from the serum of snapper (P. auratus) (Sn-PLP) to act as an opsonin. Incubation of snapper head kidney leukocytes (HKL) with FITC-labelled beads resulted in uptake of these particles by approximately 35% of HKLs. Incubation of beads with Sn-PLP enhanced phagocytosis by snapper HKLs in a dose-dependant manner. Enhanced phagocytosis could be inhibited by addition of a rabbit anti-Sn-PLP antibody suggesting that Sn-PLP may act as a ligand for a HKL cell surface receptor. This study provides further evidence toward a functional role for pentraxins in the host defence repertoire of fish.
Cook
Mathew T
MT
Dame Roma Mitchell Cancer Research Laboratories, Hanson Institute, Institute of Medical and Veterinary Science, Frome Road, Adelaide, South Australia, 5000.
Hayball
Peter J
PJ
Nowak
Barbara F
BF
Hayball
John D
JD
D000818:Animals; D001386:Azides / Q000494:pharmacology; D002097:C-Reactive Protein / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D029941:Fish Proteins / Q000097:blood* / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology; D005399:Fishes / Q000097:blood* / Q000276:immunology*; D005434:Flow Cytometry; D016650:Fluorescein-5-isothiocyanate / Q000378:metabolism; D006257:Head; D007668:Kidney; D007962:Leukocytes / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D009895:Opsonin Proteins / Q000276:immunology* / Q000494:pharmacology; D010587:Phagocytosis / Q000187:drug effects; D000683:Serum Amyloid P-Component / Q000276:immunology* / Q000302:isolation & purification / Q000494:pharmacology
D001386:Azides; D029941:Fish Proteins; D009895:Opsonin Proteins; D000683:Serum Amyloid P-Component; D002097:C-Reactive Protein; D016650:Fluorescein-5-isothiocyanate