Abstract: Provided are attenuated immunostimulatory bacteria with genomes that are modified to, for example, reduce toxicity and improve the anti-tumor activity, such as by increasing accumulation in the tumor microenvironment, particularly in tumor-resident myeloid cells, improving resistance to complement inactivation, reducing immune cell death, promoting adaptive immunity, and enhancing T-cell function. The increase in colonization of phagocytic cells improves the delivery of encoded therapeutic products to the tumor microenvironment and tumors, and permits, among other routes, systemic administration of the immunostimulatory bacteria.

Abstract: Provided are modified STING proteins that have constitutive activity, and also can have lower NF-?B signaling activity compared to unmodified human STING. Combinations and compositions containing the modified STING proteins with immunostimulatory proteins also are provided. Also provided are immunostimulatory bacteria that encode the STING proteins and the combinations, where the immunostimulatory proteins are encoded as a polycistronic message. The immunostimulatory bacteria have genomes that are modified to, for example, reduce toxicity and improve the anti-tumor activity, such as by increasing accumulation in the tumor microenvironment, particularly in tumor-resident myeloid cells, improving resistance to complement inactivation, reducing immune cell death, promoting adaptive immunity, and enhancing T-cell function.

Abstract: Provided are immunostimulatory bacteria with genomes that are modified to, for example, reduce toxicity and improve the anti-tumor activity, such as by increasing accumulation in the tumor microenvironment, particularly in tumor-resident myeloid cells, improving resistance to complement inactivation, reducing immune cell death, promoting adaptive immunity, and enhancing T-cell function. Also provided are immunostimulatory bacteria for use as vaccines, and for delivery of mRNA. The immunostimulatory bacterium comprise genome modifications resulting in an increase in colonization of phagocytic cells, which delivers encoded therapeutic products to phagocytic cells, and permits, among other routes, systemic administration of the immunostimulatory bacteria. The increase in colonization of phagocytic cells also provides for use of immunostimulatory bacteria for direct tissue administration for use as vaccines.