Methods for monitoring polymorphonuclear myeloid derived suppressor cells

Abstract

A method of obtaining a population of cells enriched in human polymorphonuclear myeloid derived suppressor cells (PMN-MDSCs) comprises isolating from a cell suspension those cells which express LOX-1 to provide a population of cells enriched with PMN-MDSCs. A method of monitoring the population of LOX-1+ cells in a cell-containing biological sample is useful for determining the efficacy of treatment or the metastasis or increasing progression of cancer. Other cell isolation and diagnostic methods are also described.

1 . A method for monitoring the population of polymorphonuclear myeloid derived suppressor cells (PMN-MDSCs) in a mammalian subject comprising:
 a. contacting a biological fluid sample from the subject containing polymorphonuclear neutrophils (PMNs) and PMN-MDSC with a ligand that specifically binds or forms a complex with LOX-1 on the cell surface; and   b. detecting and distinguishing the complexes of ligand-bound LOX-1-cells from other cells not bound to the ligand in the sample, wherein the LOX-1-bound cells are PMN-MDSCs substantially free of PMN.   
     
     
         2 . The method according to  claim 1 , further comprising counting the cells bound to the ligand to obtain a LOX-1+ population. 
     
     
         3 . The method according to  claim 1 , wherein said ligand is an anti-LOX-1 antibody, an anti-LOX-1 antibody fragment, optionally associated with a detectable label component. 
     
     
         4 . The method according to  claim 1 , further comprising contacting the sample with a ligand that specifically binds or forms a complex with a neutrophil biomarker to identify PMN in the sample. 
     
     
         5 . The method according to  claim 4 , wherein the neutrophil biomarker is CD15 or CD66b. 
     
     
         6 . The method according to  claim 5 , wherein said ligand is an anti-CD15 antibody, an anti-CD15 antibody fragment, optionally associated with a detectable label component. 
     
     
         7 . The method according to  claim 5  wherein said ligand is an anti-CD66b antibody, an anti-CD66b antibody fragment, optionally associated with a detectable label component. 
     
     
         8 . The method according to  claim 1 , wherein the ligand is immobilized on a substrate. 
     
     
         9 . The method according to  claim 1 , wherein the ligand is associated with a detectable label component that is independently detectable or is capable of generating a measurable detectable signal when contacted with another label component. 
     
     
         10 . The method according to  claim 8 , wherein the detecting step (b) comprises washing the unbound cells and other debris in the sample from the substrate and counting or collecting the bound PMN-MDSCs from the substrate. 
     
     
         11 . The method according to  claim 8 , wherein the detecting step (b) comprises treating the sample with a reagent which identifies LOX-1-PMN-MDSC complexes from unbound cells to permit enumeration of PMN-MCSC. 
     
     
         12 . The method according to  claim 1 , comprising separating bound cells from unbound cells in the sample based on size exclusion. 
     
     
         13 . The method according to  claim 1 , further comprising a step of contacting the sample with biomarkers that identify as a single population both PMN-MDSCs and PMNs and isolating a cell suspension containing both PMN-MDSCs and PMNs prior to contacting the cell suspension with the LOX-1 ligand. 
     
     
         14 . The method according to  claim 1 , wherein the biological fluid sample is whole blood and wherein the method further comprises destroying or lysing any red blood cells in the sample. 
     
     
         15 . The method according to  claim 1 , wherein the biological sample is a circulating tumor cell or fluids containing them or a tissue or tissue extract containing the PMN-MDSC. 
     
     
         16 . The method according to  claim 8 , further comprising collecting a second population which is not immobilized on the substrate, this second population containing PMNs and being substantially free from PMN-MDSCs. 
     
     
         17 . The method according to  claim 1 , comprising detecting a population of LOX-1 +  cells greater than 1% of the total neutrophil population in the sample of a subject, wherein said population of LOX-1+ cells indicates the presence, progression or metastasis of a cancer. 
     
     
         18 . The method according to  claim 1 , comprising measuring the concentration of soluble LOX-1 in the serum of the subject and correlating that concentration with the concentration of PMN-MDSC in the subject. 
     
     
         19 . The method according to  claim 1 , further comprising differentiating polymorphonuclear myeloid derived suppressor cells (PMN-MDSCs) from polymorphonuclear neutrophils (PMNs) in the biological sample. 
     
     
         20 . A method of obtaining a population of cells enriched in human polymorphonuclear myeloid derived suppressor cells (PMN-MDSCs) comprising isolating from a cell suspension those cells which express LOX-1 to provide a population of cells enriched with PMN-MDSCs.