New assays for preimplantation factor and preimplantation factor peptides

Abstract

The present invention relates to assay methods used for detecting the presence of PIF, and to PIF peptides identified using this assay. In particular, the present invention relates to flow cytometry assays for detecting PIF. It is based, at least in part, on the observation that flow cytometry using fluorescently labeled anti-lymphocyte and anti-platelet antibodies demonstrated an increase in rosette formation in the presence of PIF. It is further based on the observation that flow cytometry demonstrated that monoclonal antibody binding to CD2 decreased in the presence of PIF. The present invention further relates to PIF peptides which, when added to Jurkat cell cultures, have been observed to either (i) decrease binding of anti-CD2 antibody to Jurkat cells; (ii) increase expression of CD2 in Jurkat cells; or (iii) decrease Jurkat cell viability. In additional embodiments, the present invention provides for ELISA assays which detect PIF by determining the effect of a test sample on the binding of anti-CD2 antibody to a CD2 substrate.

1 . A method for determining the presence of preimplantation factor in a sample, comprising the step of:
 detecting whether the sample contains a component which inhibits the binding of an anti-CD2 antibody to CD2 antigen;   wherein the ability to inhibit the binding of anti-CD2 antibody to CD2 has a positive correlation with the presence of preimplantation factor.   
     
     
         2 . The method of  claim 1 , where the binding of anti-CD2 antibody to CD2 is detected using flow cytometry. 
     
     
         3 . The method of  claim 1 , where the CD2 antigen is carried by a cell. 
     
     
         4 . The method of  claim 1 , where the CD2 antigen is carried by a Jurkat cell. 
     
     
         5 . The method of  claim 2 , where the CD2 antigen is carried by a cell. 
     
     
         6 . The method of  claim 2 , where the CD2 antigen is carried by a Jurkat cell. 
     
     
         7 . The method of  claim 1 , where the binding of anti-CD2 antibody to CD2 is detected by enzyme-linked immunosorbent assay 
     
     
         8 . An isolated peptide having a sequence selected from the group consisting of: 
       
         
           
                 
               
                   Met-Val-Arg-Ile-Lys-Pro-Gly-Ser-Ala; 
                 
                     
                 
                   Met-Val-Arg-Ile-Lys-Pro-Gly-Ser-Ala-Asn-Lys- 
                 
                     
                 
                   Phe-Ser; 
                 
                     
                 
                   Met-Val-Arg-Ile-Lys-Pro-Gly-Ser-Ala-Asn-Lys-Phe- 
                 
                     
                 
                   Ser-Asp; 
                 
                   and 
                 
                     
                 
                   Met-Val-Arg-Ile-Lys-Pro-Gly-Ser-Ala-Asn-Lys-Phe- 
                 
                     
                 
                   Ser-Asp-Asp. 
                 
             
                
                
                
                
                
                
                
                
                
                
                
                
                
                
               
            
           
         
       
     
     
         9 . An isolated peptide comprising the peptide of  claim 8 , which binds to anti-CD2 antibody and which is not a circumsporooite protein. 
     
     
         10 . An isolated peptide having a sequence Ser-Gly-Ile-Val-Ile-Tyr-Gln-Tyr-Met-Asp-Asp-Arg-Tyr-Val-Gly-Ser-Asp-Leu. 
     
     
         11 . An isolated peptide comprising the peptide of  claim 10 , which binds to anti-CD2 antibody and which is not an HIV protein. 
     
     
         12 . An isolated peptide having a sequence Val-Ile-Ile-Ile-Ala-Gln-Tyr-Met-Asp. 
     
     
         13 . An isolated peptide comprising the peptide of  claim 12 , which binds to anti-CD2 antibody. 
     
     
         14 . An isolated peptide having a sequence selected from the group consisting of Ser-Gln-Ala-Val-Gln-Glu-His-Ala-Ser-Thr and Ser-Gln-Ala-Val-Gln-Glu-His-Ala-Ser-Thr-Asn-Xaa-Gly, where Xaa can be any amino acid. 
     
     
         15 . An isolated peptide comprising the peptide of  claim 14 , which binds to anti-CD2 antibody and which is not a silencing mediator for human retinoid and thyroid hormone.