SEQUENCE LISTING

The instant application contains a Sequence Listing which has been filed electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, originally filed in Application U.S. Ser. No. 15/048,922, is named 56371-720_306_SL.txt and is 169,493 bytes in size.

FIELD OF THE INVENTION

The present disclosure generally relates to the fields of genetics, immunology and medicine. The invention pertains to the field of immunotherapy, more specifically the invention pertains to the utilization of monocytes that have been manipulated to home to tumor cells and upon binding to tumor antigens differentiating into monocytes with cytotoxic properties to tumors, or dendritic cells.

BACKGROUND OF THE INVENTION

The immune system possesses the power to cure cancers based on published reports of immunologically mediated spontaneous regressions, which have been document in colon, lung, melanoma, liver, breast. Intriguingly, spontaneous regression clinically, as well as in an animal model of spontaneous regression, seems to be associated primarily with stimulation of the innate immune system, comprising of macrophages, NK cells, NKT cells and neutrophils. Despite the original promising of immunotherapy, which will be mentioned, the field has focused on the adaptive immune response, specifically stimulation of T and B cells, and only recently has interest re-ignited in the innate immune system.

The use of the immune system to treat cancer is theoretically appealing due to the possibility of low toxicity, immunological memory, and ability to attack metastatic disease. Early studies suggested that vaccination to tumor antigens and tumors themselves may be possible. Specifically, Prehn back in 1957, obtained murine tumors and exposed them to irradiation to increase immunogenicity. When these tumors were implanted into animals they were rejected. Subsequent administration of the original tumors resulted in rejection of the tumors, thus suggesting that tumor specific antigens exist, which can stimulate immunity, especially subsequent to addition of a cellular stress such as irradiation. Twenty years later, using the same system it was demonstrated that cytotoxic T cells infiltrated the tumors that were implanted after rejection of the radiation induced tumors, thus demonstrating conclusively that rejection was immunologically mediated, despite the fact that the tumors were syngeneic. In humans, one of the original observations of immunological response to neoplasia was in patients with paraneoplastic disease in which immune response to breast cancer antigens results in a multiple sclerosis-like disease caused by cross reactive immunity to neural antigens that are found on the breast cancer. Specific identification of tumor antigens on a molecular basis led to the discovery that some of the antigens are either self-proteins aberrantly expressed, or mutations of self proteins.

Originally observations were made in patients bearing metastatic melanomas, and then subsequently in other tumors, that the tumors are infiltrated with various immunological components. These tumor infiltrating lymphocytes (TILs), contain populations of cells and individual clones that demonstrate tumor specificity; they lyse autologous tumor cells but not natural killer targets, allogeneic tumor cells, or autologous fibroblasts.

By isolating and expanding TILs in vitro, and then molecularly identifying what they are responding to, a variety of the well-known tumor agents have been discovered such as MAGE-1, and MAGE-3, GAGE-1, MART-1, Melan-A, gp100, gp75 (TRP-2), tyrosinase, NY-ESO-1, mutated p16, and beta catenin. It is interesting that in the case of some antigens, such as gp75, the peptide that elicits tumor rejection results from translation of an alternative open reading frame of the same gene. Thus, the gp75 gene encodes two completely different polypeptides, gp75 as an antigen recognized by immunoglobulin G antibodies in sera from a patient with cancer, and a 24-amino acid product as a tumor rejection antigen recognized by T cells. Peptides used for immunization generally are 8-9 amino acids which have been demonstrated to be displayed in association with class I MHC molecules for recognition by T cells, and tumor cells have been shown to express these naturally processed epitopes.

Despite the intellectual appeal of peptide based cancer vaccines, the response rate has been disappointingly low. According to a review by Steven Rosenberg's group at the NIH, the rate of objective response out of 440 patients treated at his institute was a dismal 2.6%.

The ability to make a universal yet versatile system to generate T cells that are capable of recognizing various types of cancers has important clinical implications for the use of T cell-based therapies, this concept was approach initially by Rosenberg's group in the ex vivo expansion of tumor infiltrating lymphocytes. One current strategy incorporates the use of genetic engineering to express a chimeric antigen receptor (CAR) on T cells. The extracellular domain of a typical CAR consists of the VHand VLdomains—single-chain fragment variable (scFv)—from the antigen binding sites of a monoclonal antibody. The scFv is linked to a flexible transmembrane domain followed by a tyrosine-based activation motif such as that from CD3ζ. The so-called second and third generation CARs include additional activation domains from co-stimulatory molecules such as CD28 and CD137 (41BB) which serve to enhance T cell survival and proliferation. CAR T cells offer the opportunity to seek out and destroy cancer cells by recognizing tumor-associated antigens (TAA) expressed on their surface. As such, the recognition of a tumor cells occurs via an MHC-independent mechanism.

Various preclinical and early-phase clinical trials highlight the efficacy of CAR T cells to treat cancer patients with solid tumors and hematopoietic malignancies. Despite of the promise that CAR T cells might have in treating cancer patients there are several limitations to the generalized clinical application of CAR T cells. First, since no single tumor antigen is universally expressed by all cancer types, scFv in CAR needs to be constructed for each tumor antigen to be targeted. Second, the financial cost and labor-intensive tasks associated with identifying and engineering scFvs against a variety of tumor antigens poses a major challenge. Third, tumor antigens targeted by CAR could be down-regulated or mutated in response to treatment resulting in tumor evasion. Since current CAR T cells recognize only one target antigen, such changes in tumors negate the therapeutic effects. Therefore, the generation of CAR T cells capable of recognizing multiple tumor antigens is highly desired. Finally, CAR T cells react with target antigen weakly expressed on non-tumor cells, potentially causing severe adverse effects. To avoid such “on-target off-tumor” reaction, use of scFvs with higher specificity to tumor antigen is required. And although ongoing studies are focused on generating methods to shut off CAR T cells in vivo this system has yet to be developed and might pose additional inherent challenges.

The current patent seeks to apply chimeric antigen receptor technology to activation of monocytes, which naturally home into tumors, to differentiated intratumorally said monocytes into dendritic cells which are capable of antigen presentation, as well as direct killing of tumors.

