Compounds and methods for diagnosis and treatment of leishmaniasis

Abstract

Compounds and methods are provided for diagnosing, preventing, treating and detecting leishmaniasis infection and stimulating immune responses in patients are disclosed. The compounds disclosed are include polypeptides and fusion proteins that contain at least one immunogenic portion of one or more Leishmania antigens, or a variant thereof. Additionally, methods of screening a screening library for tandem repeat proteins that have immunogenic properties are disclosed. Vaccines and pharmaceutical compositions comprising polynucleotides, polypeptides, fusion proteins and variants thereof that may be used for the prevention and therapy of leishmaniasis, as well as for the detection of Leishmaniasis infection are described.

1 . A method for detecting  Leishmania  infection in a subject comprising:
 (a) contacting a biological sample from a subject suspected of having a  Leishmania  infection with one or more polypeptides, wherein each of the polypeptides comprises at least one tandem repeat unit, wherein the tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of: SEQ ID NO: 1-59, under conditions and for a time sufficient for binding of an antibody in the sample to take place; and   (b) detecting in the biological sample the presence of one or a plurality antibodies that specifically bind to the polypeptide, thereby detecting  Leishmania  infection in the biological sample.   
     
     
         2 . A method for detecting  Leishmania  infection in a biological sample according to  claim 1 , wherein the one or more polypeptides each comprises at least two tandem repeat units, wherein each tandem repeat unit comprises an amino acid sequence having at least 8 consecutive consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of: SEQ ID NO: 1-59. 
     
     
         3 . The method of  claim 1  wherein at least one of the one or more polypeptides is a fusion protein comprising at least a first and second tandem repeat unit, wherein the first tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of SEQ ID NO: 1-59; and the second tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of SEQ ID NO: 1-59. 
     
     
         4 . The method of  claim 3  wherein the first tandem repeat unit and second tandem repeat unit are identical. 
     
     
         5 . The method of  claim 3  wherein the first tandem repeat unit has at least 8 consecutive amino acids of, and at least 70% homology to the second tandem repeat unit. 
     
     
         6 . The method of  claim 1 , wherein a tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of: SEQ ID NO: 14, 17, 26, 27, 33, 43, 44. 
     
     
         7 . The method of  claim 1 , wherein clinical or sub-clinical visceral leishmaniasis infection is detected, and wherein at least one tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of: SEQ ID NO: 14, 26, 33, 44. 
     
     
         8 . The method of  claim 1 , wherein clinical or sub-clinical visceral leishmaniasis is detected, and wherein at least one tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of: SEQ ID NO: 17, 27, 43. 
     
     
         9 . The method of  claim 1 , wherein the one or more polypeptides are bound to a solid support. 
     
     
         10 . The method of  claim 9  wherein the one or more polypeptides are non-covalently bound to a solid support. 
     
     
         11 . The method of  claim 9  wherein the solid support comprises nitrocellulose, latex or a plastic material. 
     
     
         12 . The method of  claim 9  wherein the step of detecting one or a plurality of antibodies comprises:
 (a) removing unbound sample from the solid support; 
 (b) exposing a detection reagent to the solid support; and 
 (c) determining a level of antibody binding to the solid support, relative to a predetermined cutoff value, thereby detecting  Leishmania  infection in the biological sample. 
 
     
     
         13 . A diagnostic kit for detecting  Leishmania  infection in a biological sample, comprising:
 (a) one or more polypeptides, wherein each of the polypeptides comprises at least one tandem repeat unit, wherein the tandem repeat unit comprises an amino acid sequence having at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence selected from the group consisting of: SEQ ID NO: 1-59; and   (b) a detection reagent.   
     
     
         14 . The diagnostic kit of  claim 13 , further comprising a polypeptide comprising at least 8 consecutive amino acids of, and at least 70% homology to, an amino acid sequence as set forth in SEQ ID NO: 119. 
     
     
         15 . The diagnostic kit of  claim 13 , further comprising a polypeptide comprising at least 8 consecutive amino acids of, and at least 70% homology to, the amino acid sequence selected from the group consisting of: SEQ ID NO: 119-121. 
     
     
         16 - 44 . (canceled)