PDL1 block CAR-T transgenic vector for suppressing immune escape, preparation method thereof, and application of the same

A PDL1 block CAR-T transgenic vector for suppressing immune escape, comprising:

• AmpR sequence containing ampicillin resistance gene for amplifying target bacterial strains by a large number, having the sequence of SEQ ID NO:
• 1;
• prokaryotic replicon pUC Ori sequence for plasmid replication, having the sequence of SEQ ID NO:
• 2;
• SV40 Ori sequence of viral replicator for enhancing replication in eukaryotic cells, having the sequence of SEQ ID NO:
• 3;
• eWPRE enhanced posttranscriptional regulatory element of Groundhog hepatitis B virus for enhancing an expression efficiency of transgene, having the sequence of SEQ ID NO:
• 11;
• human EF1 alpha promoter for eukaryotic transcription of chimeric antigen receptor genes, having the sequence of SEQ ID NO:
• 12;
• lentivirus packaging cis-elements for lentivirus packaging;
• a nucleotide sequence encoding a humanized single chain antibody fragment of human PDL1;
• and the humanized single chain antibody fragment of the human PDL1 is PDL1scFv1 encoded by the sequence of SEQ ID NO:
• 21, or PDL1scFv2 encoded by the sequence of SEQ ID NO:
• 22, or PDL1 scFv3 encoded by the sequence of SEQ ID NO:
• 23;
• IRES ribosome binding sequence for co-transcription and expression of proteins, having the sequence of SEQ ID NO:
• 25;
• a nucleotide sequence encoding IL6 signal peptide, wherein the nucleotide sequence is shown in SEQ ID NO:
• 26;
• a nucleotide sequence encoding a human antibody Fc segment, wherein the nucleotide sequence is shown in SEQ ID NO:
• 27;
• and
• a nucleotide sequence encoding chimeric antigen receptors of a second-generation CAR or a third-generation CAR for integrating recognition, transmission and initiation.