A cytolytic function for a sialic acid-binding lectin that is a member of the pentraxin family of proteins.
A variety of invertebrates possess plasma lectins with sialic acid recognition capabilities. One of the best studied of these lectins is limulin, which is a member of the pentraxin family of proteins and is found in the plasma of the American horseshoe crab, Limulus polyphemus. We find that limulin is one of several sialic acid-binding lectins of Limulus plasma and is present at a much lower abundance than Limulus C-reactive protein, the other plasma pentraxin. Limulin was purified by sequential affinity chromatography on phosphorylethanolamine-agarose, which isolates the pentraxins and separates limulin from the other sialic acid-binding lectins of the plasma, followed by fetuin-Sepharose, which binds limulin and separates it from Limulus C-reactive protein, the most abundant pentraxin of the plasma. We show here that limulin is the mediator of the Ca+2-dependent hemolytic activity found in the plasma of Limulus. Plasma that was depleted in the pentraxins by passage over phosphorylethanolamine-agarose or was depleted in the sialic acid-binding lectins by passage over fetuin-Sepharose lacked hemolytic activity. Purified limulin was hemolytic at concentrations of 3-5 nM. The other sialic acid-binding lectins of Limulus plasma and Limulus C-reactive protein were nonhemolytic. Foreign cell cytolysis by limulin represents a novel function for a plasma lectin and is the first documented function for limulin.
Armstrong
P B
PB
Department of Molecular and Cellular Biology, University of California, Davis, California 95616-8755, USA.
Swarnakar
S
S
Srimal
S
S
Misquith
S
S
Hahn
E A
EA
Aimes
R T
RT
Quigley
J P
JP
D000818:Animals; D002097:C-Reactive Protein; D002118:Calcium / Q000494:pharmacology; D002846:Chromatography, Affinity; D002852:Chromatography, Ion Exchange; D004305:Dose-Response Relationship, Drug; D006384:Hemagglutination; D006388:Hemagglutinins / Q000302:isolation & purification; D006461:Hemolysis; D006737:Horseshoe Crabs; D007700:Kinetics; D037102:Lectins / Q000302:isolation & purification* / Q000494:pharmacology*; D009439:Neuraminidase; D012756:Sheep; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; D012794:Sialic Acids
D006388:Hemagglutinins; D037102:Lectins; D063265:Sialic Acid Binding Immunoglobulin-like Lectins; D012794:Sialic Acids; C015323:limulin; D002097:C-Reactive Protein; D009439:Neuraminidase; D002118:Calcium