Immunity to trypanosomatids species

Abstract

The present invention relates to trypanosomatid histones in substantially isolated form for use as a protective antigen against trypanosomatid infection. These histones may be either isolated from the corresponding parasite or be produced by means of recombinant DNA techniques. For the latter purpose the invention also provides genes encoding histones and derivatives of the genes like other nucleic acids and gene products like peptides and proteins. The invention further provides diagnostic tests, pharmaceutical compositions and vaccines comprising the usual excipients and/or adjuvants and at least one histone, a histone encoding gene or a derivative thereof.

1 . Trypanosomatid histones in substantially isolated form for use as a protective antigen against trypanosomatid infection.  
     
     
         2 . Histones as claimed in  claim 1 , wherein the trypanosomatid is a Leishmania species, for example of the subgenus Leishmania, comprising the species  L.major, L.chagasi, L.donovani, L.infantum, L.mexicana, L.amazonensis,  and species of the subgenus Viannia, comprising  L.braziliensis, L.peruviana, L.guyanensis, L.panamensis,  and the trypanosomatid infection leishmaniasis.  
     
     
         3 . Histones as claimed in  claim 1 , wherein the trypanosomatid is a Trypanosoma species, such as  T.cruzi, T.brucei.    
     
     
         4 . Histones as claimed in any one of the  claims 1  to  3 , which histones are H1 histones.  
     
     
         5 . Leishmania gene encoding a histone polypeptide as claimed in  claim 2  or  4 , which polypeptide has a protective capacity against leishmaniasis, and wherein the gene has a nucleotide sequence that can hybridise with: 
 a) at least a distinguishing part of the polynucleotide of the sequence depicted in FIG. 6A; or  
 b) those parts of the sequence of FIG. 6A that encode a part/parts of the histone that is/are responsible for the protective capacity of the polypeptide; or  
 c) the complementary strand of either a) or b).  
 
     
     
         6 . Leishmania gene as claimed in  claim 5 , characterized in that the gene originates from  L.major  and the coding region thereof has essentially the nucleotide sequence depicted in FIG. 6B, or the complementary strand thereof.  
     
     
         7 . Leishmania gene as claimed in  claim 5 , characterized in that the gene originates from  L.major  and the coding region thereof has essentially the nucleotide sequence depicted in FIG. 6C, or the complementary strand thereof.  
     
     
         8 . Derivatives of the Leishmania gene as claimed in claims  5 - 7 , which derivatives comprise fragments of the gene, complete or partial cDNAs of the gene, complete or partial mRNAs to the gene, complete or partial proteins encoded by the gene, peptides comprising at least an immunogenic part of the protein, antisense oligo- or polynucleotides, fusion products between at least part of the gene, cDNA, mRNA, protein or peptide and at least part of another gene, cDNA, mRNA, protein or peptide, antibodies against the gene, cDNA, mRNA, protein, peptides or fusion products thereof, primers specific for the gene, cDNA or mRNA, wherein each derivative may either be isolated or may be obtained through recombinant DNA techniques.  
     
     
         9 . Derivative as claimed in  claim 8 , characterized in that the derivative is an antibody directed against the peptide having the amino acid sequence: 
 NH 2 -MSSNSAAAAVSAATTSPQKS-COOH.    
     
     
         10 . Leishmania genes and/or their derivatives as claimed in claims  5 - 9  for use in diagnosis, prophylaxis and therapy of parasite infections.  
     
     
         11 . Leishmania genes and/or their derivatives for the use as claimed in  claim 10 , characterized in that the parasite infection is a trypanosomatid infection, in particular a Leishmania infection.  
     
     
         12 . Leishmania genes and/or their derivatives for the use as claimed in  claim 11 , characterized in that the Leishmania infection is an infection by one or more of the Leishmania species selected from the group consisting of the subgenus Leishmania, consisting of  L.major, L.chagasi, L.donovani, L.infantum, L.mexicana, L.amazonensis,  and species of the subgenus Viannia, consisting of  L.braziliensis, L.peruviana, L.guyanensis, L.panamensis.    
     
     
         13 . Use of Leishmania genes and/or their derivatives as claimed in claims  5 - 9  for the preparation of diagnostic tests, prophylactic compositions or therapeutic compositions for the treatment of parasite infections, in particular trypanosomatid infections, such as Leishmania infections, for example caused by one or more of the Leishmania species selected from the group consisting of the subgenus Leishmania, consisting of  L.major, L.chagasi, L.donovani, L.infantum, L.mexicana, L.amazonensis,  and species of the subgenus Viannia, consisting of  L.braziliensis, L.peruviana, L.guyanensis, L.panamensis.    
     
     
         14 . DNA construct, comprising one or more of the genes as claimed in claims  5 - 7 , or fragments or cDNAs thereof, or fusion products comprising at least part of the gene, operably linked to appropriate expression signals.  
     
     
         15 . Vector carrying a DNA construct as claimed in  claim 14 .  
     
     
         16 . Vector as claimed in  claim 15 , characterized in that the vector is the pGEX-KG-415 plasmid as defined in the description.  
     
     
         17 . Host organism harbouring a DNA construct as claimed in  claim 14  and/or a vector as claimed in claims  15  and  16 .  
     
     
         18 . Diagnostic test, comprising the usual reagents and materials and a diagnostic agent which is suitable for assaying the presence of an infectious agent in a subject and is selected from the genes as claimed in claims  5 - 7  or the derivatives as claimed in  claim 8  or  9 .  
     
     
         19 . Diagnostic test as claimed in  claim 18 , wherein the test is suitable for assaying the presence of an infectious agent in a body fluid of the subject.  
     
     
         20 . Vaccine composition comprising the usual carriers and/or adjuvants and at least one histone as claimed in claim  1 - 4  and/or one or more derivative as claimed in  claim 8  or  9 , which histone or derivative is capable of eliciting protective immunity in a subject receiving the composition.  
     
     
         21 . Histones as claimed in claim  1 - 4 , obtainable by the method comprising the steps of: 
 a) lysing cells of a trypanosomatid species to obtain a lysate;    b) isolating nuclei from the lysate;    c) resuspending the nuclei in an extraction medium, for example either a 0.5-2.5 N, preferably a 1.25 N HCl solution for obtaining total histones, or 1-10%, preferably 5% perchloric acid for obtaining histone H1, to obtain a histone solution;    d) optionally removing insoluble proteins from the histone solution;    e) precipitating the histones by adding a precipitation agent, for example an excess of cold acetone for total histone or cold ethanol for histone H1.    
     
     
         22 . Histones as claimed in claim  1 - 4  or  21  for use in diagnosis, prophylaxis and therapy of parasite infections, in particular trypanosomatid infections, such as Leishmania infections, for example caused by one or more of the Leishmania species selected from the group consisting of species of the subgenus Leishmania, consisting of  L.major, L.chagasi, L.donovani, L.infantum, L.mexicana, L.amazonensis,  and species of the subgenus Viannia, consisting of  L.braziliensis, L.peruviana, L.guyanensis, L.panamensis.    
     
     
         23 . Histones as claimed in  claim 21  for use as a starting point for isolating genes encoding protective antigens and/or derivatives of the genes.  
     
     
         24 . Use of one or more histones as claimed in claim  1 - 4  or  21  for the preparation of diagnostic tests, prophylactic compositions or therapeutic compositions for the treatment of parasite infections, in particular trypanosomatid infections, such as Leishmania infections, for example caused by one or more of the Leishmania species selected from the group consisting of species of the subgenus Leishmania, consisting of  L.major, L.chagasi, L.donovani, L.infantum, L.mexicana, L.amazonensis,  and species of the subgenus Viannia, consisting of  L.braziliensis, L.peruviana, L.guyanensis, L.panamensis.    
     
     
         25 . Use of intracellular or nuclear proteins as protective antigens for the treatment and/or prophylaxis of parasite infections.