Abstract: It is an object of the present invention to provide signal sequence information capable of secreting an antibody to the outside of cells in generation of the antibody by microorganisms of genus Bifidobacterium, and an antibody expression vector capable of secreting an antibody to the outside of cells by utilizing the signal sequence information. As a means for achieving the aforementioned object, there is prepared Bifidobacterium longum, which is transformed with a vector having inserted thereinto a DNA insert comprising the 5?-terminus of an antibody gene linked to the 3?-terminus of a DNA encoding a signal peptide-linker conjugate having a linker linked to the C-terminus of a signal peptide consisting of an amino acid sequence shown in SEQ ID NO: 1.

Abstract: It is an object of the present invention to provide signal sequence information capable of secreting an antibody to the outside of cells in generation of the antibody by microorganisms of genus Bifidobacterium, and an antibody expression vector capable of secreting an antibody to the outside of cells by utilizing the signal sequence information. As a means for achieving the aforementioned object, there is prepared Bifidobacterium longum, which is transformed with a vector having inserted thereinto a DNA insert comprising the 5?-terminus of an antibody gene linked to the 3?-terminus of a DNA encoding a signal peptide-linker conjugate having a linker linked to the C-terminus of a signal peptide consisting of an amino acid sequence shown in SEQ ID NO: 1.

Abstract: An object of the present invention is to provide a method of efficiently constructing a gene delivery carrier having a favorable activity and expression efficiency of a protein expressed by a gene introduced by transformation. Moreover, an object of the present invention is to provide a pharmaceutical composition comprising a gene delivery carrier constructed by the construction method and a therapeutic agent for solid tumor comprising the resistant bacterium.

Abstract: The present invention provides a method for producing a cytosine deaminase (CD)-expressing, 5-fluorouracil (5-FU)-resistant microorganism which can grow in anaerobic tumor tissues, can express CD, and has a resistance to 5-FU at a concentration that is at least effective for antitumor activity. More specifically, the method is a method (A) comprising performing subculture or acclimation culture of a CD-expressing microorganism which can grow in anaerobic tumor tissues, in the presence of 5-fluorocytosine (5-FC), or a method (B) comprising (1) performing subculture or acclimation culture of a microorganism which can grow in anaerobic tumor tissues and does not express CD, in the presence of 5-FU to produce a 5-FU-resistant microorganism and (2) transforming the 5-FU-resistant microorganism by introducing a CD gene. The present invention also provides the CD-expressing, 5-FU-resistant microorganism and a pharmaceutical composition comprising the microorganism.

Abstract: The present invention provides an obligately anaerobic lactic acid bacterium having no risk of causing side effects in normal tissue and promising as a safe therapeutic agent and a gene transporter for a disease that is in an anaerobic environment such as a solid tumor, a preparation method therefor, and an expression vector useful in the preparation method. The obligately anaerobic lactic acid bacterium of the present invention has been artificially mutated from being facultatively anaerobic to being obligately anaerobic and, furthermore, is capable of being transformed by an expression vector having introduced thereinto a gene for expressing an active protein useful for the treatment of a disease that is in an anaerobic environment.

Abstract: The present invention provides a shuttle vector for a microorganism of the genus Bifidobacterium (BM) and Escherichia coli having a wide host range and a large copy number in BM and capable of highly expressing a desired protein when used as an expression vector; an expression vector capable of expressing a desired gene in BM by use of the shuttle vector; BM transformed with the expression vector; and an antitumor agent comprising the BM as an active ingredient. It comprises a pTB6-derived region portion comprising a replication origin (oriV)-repB region of pTB6 but not comprising MembB, MobA, OrfI, and oriT regions of pTB6 and an Escherichia coli-derived plasmid portion comprising a replication origin (Puc Ori) region of Escherichia coli but having deleted DNA encoding an N-terminal region of an ampicillin resistance gene (ampR) expression product ?-lactamase.

Abstract: The present invention provides an obligately anaerobic lactic acid bacterium having no risk of causing side effects in normal tissue and promising as a safe therapeutic agent and a gene transporter for a disease that is in an anaerobic environment such as a solid tumor, a preparation method therefor, and an expression vector useful in the preparation method. The obligately anaerobic lactic acid bacterium of the present invention has been artificially mutated from being facultatively anaerobic to being obligately anaerobic and, furthermore, is capable of being transformed by an expression vector having introduced thereinto a gene for expressing an active protein useful for the treatment of a disease that is in an anaerobic environment.

Abstract: The present invention provides a bacterium belonging to the genus Bifidobacterium, by which DNA coding for a protein having an antitumor activity or DNA coding for a protein having the activity of converting a precursor of an antitumor substance into the antitumor substance is delivered to tumor tissues specifically under anaerobic conditions thereby expressing the protein encoded by the DNA, as well as a pharmaceutical composition comprising said anaerobic bacterium.

Abstract: The present invention provides a shuttle vector for a microorganism of the genus Bifidobacterium (BM) and Escherichia coli having a wide host range and a large copy number in BM and capable of highly expressing a desired protein when used as an expression vector; an expression vector capable of expressing a desired gene in BM by use of the shuttle vector; BM transformed with the expression vector; and an antitumor agent comprising the BM as an active ingredient. It comprises a pTB6-derived region portion comprising a replication origin (oriV)-repB region of pTB6 but not comprising MembB, MobA, OrfI, and oriT regions of pTB6 and an Escherichia coli-derived plasmid portion comprising a replication origin (oriC) region of Escherichia coli but having deleted DNA encoding an N-terminal region of an ampicillin resistance gene (ampR) expression product ?-lactamase, and constitute a shuttle vector for Escherichia coli with a BM having an average copy number of 6 to 30.

Abstract: The present invention provides a method for producing a cytosine deaminase (CD)-expressing, 5-fluorouracil (5-FU)-resistant microorganism which can grow in anaerobic tumor tissues, can express CD, and has a resistance to 5-FU at a concentration that is at least effective for antitumor activity. More specifically, the method is a method (A) comprising performing subculture or acclimation culture of a CD-expressing microorganism which can grow in anaerobic tumor tissues, in the presence of 5-fluorocytosine (5-FC), or a method (B) comprising (1) performing subculture or acclimation culture of a microorganism which can grow in anaerobic tumor tissues and does not express CD, in the presence of 5-FU to produce a 5-FU-resistant microorganism and (2) transforming the 5-FU-resistant microorganism by introducing a CD gene. The present invention also provides the CD-expressing, 5-FU-resistant microorganism and a pharmaceutical composition comprising the microorganism.

Abstract: An object of the present invention is to provide a method of efficiently constructing a gene delivery carrier having a favorable activity and expression efficiency of a protein expressed by a gene introduced by transformation. Moreover, an object of the present invention is to provide a pharmaceutical composition comprising a gene delivery carrier constructed by the construction method and a therapeutic agent for solid tumor comprising the resistant bacterium.

Abstract: The present invention provides a bacterium belonging to the genus Bifidobacterium, by which DNA coding for a protein having an antitumor activity or DNA coding for a protein having the activity of converting a precursor of an antitumor substance into the antitumor substance is delivered to tumor tissues specifically under anaerobic conditions thereby expressing the protein encoded by the DNA, as well as a pharmaceutical composition comprising said anaerobic bacterium.