Methods and compositions for genetically modifying lymphocytes to express polypeptides comprising the intracellular domain of MPL

A replication incompetent recombinant retroviral particle comprising:

• A. one or more pseudotyping elements on the surface of the replication incompetent recombinant retroviral particle;
• and
• B. a polynucleotide comprising one or more transcriptional units, wherein each of the one or more transcriptional units is operatively linked to a promoter active in T cells, and wherein the one or more transcriptional units encode:
• i. a first engineered signaling polypeptide, wherein said first engineered signaling polypeptide is a chimeric polypeptide comprising an extracellular domain, a transmembrane domain, and a first intracellular signaling domain comprising a cytokine receptor polypeptide that is capable of activating a cellular signaling pathway, wherein said transmembrane domain is covalently attached to said extracellular domain and said first intracellular signaling domain,
• wherein said transmembrane domain is between 15 and 100 amino acids,
• wherein said first intracellular signaling domain comprises an intracellular signaling domain of thrombopoietin receptor having at least 90% sequence identity to the sequence of SEQ ID NO:283, and comprises a JAK-2 binding domain comprising a Box1 motif according to SEQ ID NO:306, and
• wherein said extracellular domain comprises a leucine zipper dimerizing motif, and
• ii. a second engineered signaling polypeptide comprising a chimeric antigen receptor (CAR).