Cmv vectors comprising microrna recognition elements

Abstract

Disclosed herein are recombinant CMV vectors comprising heterologous antigens and microRNA recognition elements to silence expression of CMV genes in the presence of microRNA derived from myeloid cells, an active UL128 protein and an active UL130 protein. Also disclosed are recombinant CMV vectors comprising heterologous antigens and microRNA recognition elements to silence expression of CMV genes in the presence of microRNA derived from myeloid cells, an inactive UL128 protein and an inactive UL130 protein. Also disclosed are methods of generating an unconventional immune response using these vectors. Such an immune response is characterized by generation of a CD8+ T cell response that is predominantly restricted by MHC-II.

1 - 21 . (canceled) 
     
     
         22 . A cytomegalovirus (CMV) vector comprising:
 (a) a first nucleic acid sequence encoding at least one heterologous antigen;   (b) a second nucleic acid sequence comprising a first microRNA recognition element (MRE) operably linked to a CMV gene that is essential or augmenting for CMV growth and wherein the MRE silences expression in the presence of a microRNA that is expressed by a cell of myeloid lineage;   where the CMV vector does not express an active lacks an UL128 protein or ortholog thereof; and does not express an active UL130 protein or ortholog thereof.   
     
     
         23 . The CMV vector of  claim 22 , wherein the first MRE silences in the presence of one or more of miR-142-3p, miR-223, miR-27a, miR-652, miR-155, miR146a, miR-132, miR-21, or miR-125. 
     
     
         24 . The CMV vector of  claim 22 , wherein the at least one heterologous antigen comprises a pathogen-specific antigen, a tumor antigen, a tissue-specific antigen, or a host self-antigen. 
     
     
         25 . The CMV vector of  claim 24 , wherein the host self-antigen is an antigen derived from the variable region of a T cell receptor (TCR) or an antigen derived from the variable region of a B cell receptor. 
     
     
         26 . The CMV vector of  claim 24 , wherein the pathogen-specific antigen is derived from a pathogen selected from the group consisting of: human immunodeficiency virus, simian immunodeficiency virus, herpes simplex virus, hepatitis B virus, hepatitis C virus, papillomavirus, Plasmodium parasites, and Mycobacterium tuberculosis. 
     
     
         27 . The CMV vector of  claim 24 , wherein the tumor antigen is related to a cancer selected from the group consisting of: acute myelogenous leukemia, chronic myelogenous leukemia, myelodysplastic syndrome, acute lymphoblastic leukemia, chronic lymphoblastic leukemia, non-Hodgkin's lymphoma, multiple myeloma, malignant melanoma, breast cancer, lung cancer, ovarian cancer, prostate cancer, pancreatic cancer, colon cancer, renal cell carcinoma (RCC), and germ cell tumors. 
     
     
         28 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active UL82 (pp71) protein, US11, or an ortholog thereof. 
     
     
         29 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active UL79 protein, or an ortholog thereof. 
     
     
         30 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active US11 protein, or an ortholog thereof. 
     
     
         31 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active UL79 protein or an active UL82 (pp71) protein, or orthologs thereof. 
     
     
         32 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active UL82 (pp71) protein or an active US11 protein, or orthologs thereof. 
     
     
         33 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active UL79 protein or an active US11 protein, or orthologs thereof. 
     
     
         34 . The CMV vector of  claim 22 , wherein the CMV vector does not express an active UL79 protein, an active UL82 (pp71) protein, or an active US11 protein, or orthologs thereof. 
     
     
         35 . The CMV vector of  claim 22 , wherein the CMV vector is a human CMV (HCMV) or rhesus CMV (RhCMV) vector. 
     
     
         36 . A method of generating an immune response to at least one heterologous antigen in a subject, the method comprising administering to the subject the CMV vector of  claim 22  in an amount effective to elicit a CD8+ T cell response to the at least one heterologous antigen in the subject. 
     
     
         37 . The method of  claim 36 , wherein at least 10% of the CD8+ T cells elicited by the CMV vector are restricted by Class II MHC or an ortholog thereof. 
     
     
         38 . The method of  claim 37 , wherein at least 20%, at least 30%, at least 40%, at least 50%, at least 60% or at least 75% of the CD8+ T cells are restricted by Class II MHC or an ortholog thereof. 
     
     
         39 . The method of  claim 38 , wherein CD8+ T cells restricted by MHC-II recognize “supertopes”, i.e. peptides that are presented by multiple different MHC-II alleles. 
     
     
         40 . The method of  claim 38 , wherein fewer than 10% of the CD8+ T cells are restricted by MHC-I or an ortholog thereof. 
     
     
         41 . The method of  claim 36 , wherein the subject has been previously exposed to CMV. 
     
     
         42 . The method of  claim 36 , wherein the subject is a human or nonhuman primate. 
     
     
         43 . The method of  claims 36 , wherein administering the CMV vector comprises subcutaneous, intravenous, intramuscular, intraperitoneal, or oral administration of the CMV vector. 
     
     
         44 . The CMV vector of  claim 22 , wherein the first MRE of the CMV vector silences expression of IE2 or UL79, or an ortholog thereof, in the presence of miR-142-3p.