Compositions and methods for activating toll-like receptor 4

Abstract

Methods for activating Toll-like receptor 4 via cholesterol-dependent cytolysins isolated from a Gram-positive bacteria are provided. In addition compositions containing an isolated cholesterol-dependent cytolysin or a fragment thereof or a mimetic of the cytolysin or fragment thereof and methods for use of such composition in inhibiting binding and/or interaction of Toll-like receptor 4 with endotoxin are provided. Methods for identifying modulators of Toll-like receptor 4 activation by a cholesterol-dependent cytolysin and use of such modulators in treatment of septicemia and/or septic shock are also provided.

1 . A method for activating Toll-like receptor 4 comprises contacting Toll-like receptor 4 with a cholesterol-dependent cytolysin isolated from a Gram-positive bacteria.  
     
     
         2 . The method of  claim 1  wherein the cholesterol-dependent cytolysin is Listeriolysin O, Streptolysin O, perfringolysin O, or anthrolysin O.  
     
     
         3 . A composition comprising an isolated cholesterol-dependent cytolysin from a Gram-positive bacteria or a fragment thereof or a mimetic of the isolated cholesterol-dependent cytolysin from a Gram-positive bacteria or the fragment thereof which inhibits binding of Toll-like receptor 4 and endotoxin.  
     
     
         4 . The composition of  claim 3  further comprising an acceptable carrier or vehicle for administration of a subject.  
     
     
         5 . A method of inhibiting binding and/or interaction of Toll-like receptor 4 with endotoxin in a subject comprising administering to the subject the composition of  claim 3 .  
     
     
         6 . A method of inhibiting binding and/or interaction of Toll-like receptor 4 with endotoxin in a subject comprising administering to the subject the composition of  claim 4 .  
     
     
         7 . A method for treating septicemia or septic shock in a subject comprising administering to the subject the composition of  claim 3 .  
     
     
         8 . A method for treating septicemia or septic shock in a subject comprising administering to the subject the composition of  claim 4 .  
     
     
         9 . A method for identifying a modulator of Toll-like receptor 4 activation comprising: 
 (a) measuring activation of Toll-like receptor 4 by a cholesterol-dependent cytolysin in the presence and absence of a test agent; and    (b) comparing the measured activation of Toll-like receptor 4 by the cholesterol-dependent cytolysin in the absence of the test agent with the measured activation of Toll-like receptor 4 by the cholesterol-dependent cytolysin in the presence of a test agent,    wherein any change in activation of Toll-like receptor 4 activity by the cholesterol-dependent cytolysin in the presence of the test agent is indicative of the test agent being a modulator of Toll-like receptor 4 activation.    
     
     
         10 . A composition for treatment of septicemia or septic shock comprising an agent which inhibits activation of Toll-like receptor 4 by a cholesterol-dependent cytolysin.  
     
     
         11 . A method for treating septicemia or septic shock in a subject comprising administering to the subject the composition of  claim 10.