Bacterial effector as anti-bacterial protein
Disclosed are methods of using the Legionella pneumophilia effector protein, LegC4, either intracellularly generated or extracellularly delivered to cells, as an anti-microbial agent to treat or prevent intracellular microbial infections.
1 . A method of treating mammalian cells to suppress the numbers of an intracellular pathogen present in mammalian cells contacted with said intracellular pathogen, relative to non-treated mammalian cells contacted with said intracellular pathogen, said method comprising increasing the intracellular concentration in said mammalian cells, of a polypeptide having at least 95% sequence identity to SEQ ID NO: 2, or having at least 95% sequence identity to a peptide fragment of SEQ ID NO: 2, wherein said fragment is at least 20 amino acids in length via administering the polypeptide or a polynucleotide encoding said polypeptide to the mammalian cells, with the proviso that the intracellular pathogen is not Legionella pneumophilia.
2 . The method of claim 1 wherein the step of increasing the intracellular concentration of said polypeptide comprises delivering an exogenous source of said polypeptide, or a polynucleotide encoding said polypeptide, into said mammalian cells.
3 . The method of claim 1 wherein the intracellular concentration of said polypeptide is increased by transfecting said cells with a polynucleotide that encodes a polypeptide having at least 95% sequence identity to SEQ ID NO: 2.
4 . The method of claim 3 wherein said cells are transfected with a polynucleotide having at least 95% sequence identity to SEQ ID NO: 1.
5 . The method of claim 1 wherein the mammalian cell is a human cell.
6 . The method of claim 1 wherein the intracellular pathogen is an intracellular bacterial pathogen selected from the group consisting of Brucella abortus, Listeria monocytogenes, Chlamydia trachomatis, Coxiella burnetii, Mycobacterium tuberculosis, Salmonella enterica, Pseudomonas aeruginosa, Yersinia pestis, Burkholderia pseudomallei and Burkholderia mallei.
7 . The method of claim 1 wherein the intracellular pathogen is Listeria monocytogenes, Pseudomonas aeruginosa or Salmonella enterica.
8 . The method of claim 1 wherein the intracellular pathogen is a viral pathogen.
9 . The method of claim 1 wherein said cell is treated in vivo and the method comprises administering to a subject a composition comprising a delivery vehicle that delivers said polypeptide and/or said polynucleotide into the cytosol of the subject's cells.
10 . The method of claim 9 wherein the delivery vehicle is an extracellular vesicle.
11 . The method of claim 9 wherein the delivery vehicle is a viral vector.
12 . A method of inhibiting the infection of a human cell by an intracellular pathogen, said method comprising the step of increasing the intracellular concentration in said human cell, of a polypeptide having at least 95% sequence identity to SEQ ID NO: 2 (LegC4), or having at least 95% sequence identity to a peptide fragment of SEQ ID NO: 2, wherein said fragment is at least 20 amino acids in length via administering the polypeptide or a polynucleotide encoding said polypeptide to the human cell, with the proviso that the intracellular pathogen is not Legionella pneumophilia.
13 . The method of claim 12 wherein the intracellular pathogen is a bacterial intracellular pathogen selected from the group consisting of Brucella abortus, Listeria monocytogenes, Chlamydia trachomatis, Coxiella burnetii, Mycobacterium tuberculosis, Salmonella enterica, Pseudomonas aeruginosa, Yersinia pestis, Burkholderia pseudomallei and Burkholderia mallei.
14 . The method of claim 13 wherein the intracellular pathogen is Listeria monocytogenes, Pseudomonas aeruginosa or Salmonella enterica.
15 . The method of claim 12 wherein the intracellular pathogen is a viral pathogen.
16 . The method of claim 13 wherein the intracellular concentration of a polypeptide having at least 95% sequence identity to SEQ ID NO: 2 is increased by transfecting said cell with a polynucleotide that encodes said polypeptide.
17 . The method of claim 16 wherein the cell is transfected with a polynucleotide having at least 95% sequence identity to SEQ ID NO: 1.
18 . A method of treating mammalian cells to suppress the numbers of an intracellular viral pathogen present in mammalian cells contacted with said intracellular viral pathogen, relative to non-treated mammalian cells contacted with said intracellular viral pathogen, said method comprising transfecting the cells with a nucleic acid that encodes for a polypeptide having at least 95% sequence identity to SEQ ID NO: 2 or a peptide fragment of SEQ ID NO: 2, wherein said peptide fragment is at least 20 amino acids in length.
19 . The method of claim 18 , wherein the cells are human cells that are transfected with a polynucleotide having at least 95% sequence identity to SEQ ID NO: 1.