| CPC C12Q 1/6886 (2013.01) [C07K 14/7051 (2013.01); G01N 33/505 (2013.01); C12Q 2600/156 (2013.01); C12Q 2600/158 (2013.01); G01N 2333/7051 (2013.01)] | 16 Claims |
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1. A method for identifying a shared neoantigen-reactive T cell receptor (TCR), comprising steps performed in the following specific order:
(A) collecting and processing sample of a subject with a cancer, comprising:
isolating peripheral blood mononuclear cells (PBMCs) from peripheral blood sample from the subject with cancer; and
employing next-generation genomic and transcriptomic sequencing on a sample of tumor tissue and white blood cells, and using bioinformatic analysis to obtain a plurality of mutation sequences and a plurality of wild-type sequences corresponding to the mutant sequences;
(B) selecting the mutation sequences at step (A) presented in a collection of 67 off-the-shelf peptides to obtain a shared neoantigen; wherein the collection of 67 off-the-shelf peptides consists of KRAS_p.G13D, KRAS_p.G12V, KRAS_p.G12A, KRAS_p.G12D, KRAS_p.G12C, CDX2_p.V306X, RNF43_p.G659X, TP53_p.R282W, TP53_p.R273H, TP53_p.R248Q, TP53_p.R175H, GNAS_p.R201H, PIK3CA_p.E545K, BRAF_p.V640E, TCF7L2_p.R471C, ATM_p.A2301X, POU2AF1_p.A226V, KRAS_p.G12S, CHD4_p.K73X, TP53_p.E286K, TP53_p.Y220C, TP53_p.C176F, TP53_p.A159P, TP53_p.V157F, CIC_p.T1740M, ELK4_p.S359X, ARID1A_p.K1071X, BARD1_p.K171X, PIK3CA_p.V344G, PIK3CA_p.E542K, AKAP9_p.SE1650-1651 SX, TCF7L2_p.H198X, ATM_p.V60X, BCL9L_p.Q452X, NCOR2_p.P975X, KRAS_p.A146T, BRCA2_p.Q1782X, CDK12_p.R663C, TP53_p.R273C, SMAD4_p.G30X, SMAD4_p.R361H, MTOR_p.S2215F, ATP1A1_p.G98X, ARID1A_p.S764SX, ARIDIA_p.G1848X, ASXL1_p.G643X, GNAS_p.R201C, ERG_p.446-447X, AMER1_p.F173X, DCTN1_p.R1173H, PIK3CA_p.R88Q, PIK3CA_p.R357Q, PIK3CA_p.E545A, PIK3CA_p.E970K, FAT4_p.L3V, FBXW7_p.S582L, FBXW7_p.R465H, PDGFRA_p.R151H, APC_p.M1413X, APC_p.KR1462-1463X, IL7R_p.K119X, IL6ST_p.K529X, BRAF_p.D634N, BRAF_p.G509V, EGFR_p.L858R, AKAP9_p.K37X, and UBR5_p.R1331C;
(C) synthesizing a long peptide corresponding to a panel of shared neoantigen and its corresponding wild type peptides;
(D) stimulating the PBMCs with the long synthetic peptide to obtain a stimulated PBMC, comprising the following steps:
(i) thawing frozen PBMCs in activated immune cell medium-v media supplemented with 10% fetal bovine serum (FBS) and 1 μg/mL deoxyribonuclease I (DNase I) solution;
(ii) allowing 105 PBMCs to rest in 96-round bottom well-plate containing activated immune cell medium-v media supplemented with 10% FBS, 10 mM N-2-hydroxyethylpiperazine-N′-2-ethanesulfonic acid (HEPES), and 50 μM β-mercaptoethanol overnight before stimulation with synthesized long peptide at a concentration of 5 μM in a humidified incubator at 37° C. with 5% CO2;
(iii) further stimulating PBMCs with 2000 IU/mL granulocyte-macrophage colony-stimulating factor (GM-CSF) and 1000 IU/mL interleukin-4 (IL-4) for 24 hours;
(iv) adding 100 ng/mL LPS and 10 ng/mL IFN-y to the PBMCs along with the peptide for an additional 12 hours; and
(v) restimulating PBMCs by adding 10 ng/mL interleukin-7 (IL-7), 10 ng/mL interleukin-15 (IL-15), and 10 ng/mL interleukin-21 (IL-21) to the PBMCs, in which the step (v) is repeated three times and each time is 3 days apart;
(E) screening the stimulated PBMC based on induction of IFN-γ secretion of neoantigen-specific T cells, wherein the mutant peptides induced twofold higher T cell responses than corresponding wild-type sequences;
(F) isolating a neoantigen-specific T cell from the screened stimulated PBMC to identify a clonotype-purified cell, comprising steps (a1) to (a7):
(a1) determining the viability of the stimulated PBMC using a hemocytometer to ensure viability above 90%, and adjusting a cell concentration to between 700-1,200 cells per microliter to obtain a uniform PBMC suspension;
(a2) mixing the uniform PBMC suspension at step (a1) with a reverse transcription (RT) master mix to obtain a cell-master mix solution, then loading the cell-master mix solution onto a microfluidic device configured to partition individual cells into emulsions for unique nucleic acid barcoding, wherein the loading is performed along with barcoded 5′ gel beads and partitioning oil to obtain single-cell gel beads in emulsion (GEMs); and
(a3) performing cell lysis and barcoded reverse transcription of RNA within each of the GEMs to obtain a barcoded complementary DNA (cDNA);
(a4) producing and validating cDNA of gene expression library and VDJ library, comprising:
recovering the barcoded cDNA from the GEMs at step (a3) to obtain a cDNA sample;
amplifying the cDNA sample using polymerase chain reaction (PCR) to obtain an amplified cDNA; and
assessing the quality of the amplified cDNA using sensitivity-based screening systems to obtain a validated cDNA;
(a5) constructing sequencing libraries, comprising:
utilizing the validated cDNA at step (a4) to prepare 5′ gene expression libraries;
indexing each library with a sample indexing system to obtain an indexed gene expression library; and
sequencing the indexed gene expression library on a sequencing platform to generate at least 30,000 read pairs per cell with paired-end reads of 2×300 base pairs;
(a6) enriching and sequencing V(D)J regions, and RNA transcriptomic profile comprising:
using the libraries generated in step (a5) to amplify full-length variable (V), diversity (D), and joining (J) segments of T cell receptor (TCR) alpha and beta chains using an enrichment system to obtain an enriched TCR product;
quantifying the enriched TCR product obtained from the amplification using sensitivity-based quantification systems to produce a quantified enriched TCR product;
preparing sequencing libraries using 50 ng of the quantified enriched TCR product to produce a TCR sequencing library; and
sequencing the TCR sequencing library on a sequencing platform to generate paired-end reads of 2×300 base pairs with a depth of 5,000 read pairs per cell; and
(a7) performing bioinformatics analyses on the single cell gene expression data to identify the clonotype-purified cell, comprising:
retaining cells with available clonotype information; and
excluding cells with mitochondrial genome-derived reads exceeding 15%, more than 7,000 detected genes, or more than two TRA (T-cell receptor alpha locus) or TRB (T-cell receptor beta locus) sequences to obtain the clonotype-purified cell;
(G) identifying a TCR candidate for shared neoantigen by performing steps (b1) to (b5):
(b1) isolating CD3+ T cells from both mutant and wild-type groups by a combination of positive selection for CD3+ cells and filtering based on gene expression and mitochondrial gene expression;
(b2) defining a T cell activation score based on the average expression of 10 genes associated with T cell activation for each T cell, in which the 10 genes associated consist of interferon gamma (IFNG), interleukin-2 (IL-2), tumor necrosis factor (TNF), interleukin-2 receptor alpha (IL2RA), cluster of differentiation 69 (CD69), TNF receptor superfamily member 9 (TNFRSF9), granzyme B (GZMB), granzyme A (GZMA), granzyme K (GZMK), and perforin 1 (PRF1);
(b3) normalizing the size of TCR clonotypes stimulated by mutant sequences relative to the corresponding wild-type sequences; wherein, if any TCR clonotype is stimulated only by mutant sequences and is not found in the sample stimulated by the corresponding wild-type sequences, its size is calculated by taking the smallest size of the TCR clonotype stimulated by the wild-type sequences;
(b4) calculating a ratio size of each TCR clonotype from group which is stimulated by mutant sequences compared to the corresponding wild-type sequences; and
(b5) ranking the clonotypes based on their IFNG expression and T cell activation score at step (b2), and their ratio size at step (b4) to identify the TCR candidate for shared neoantigen;
(H) evaluating antigenic specificity of the TCR candidate for shared neoantigen through T cell activation bioassay using Nuclear Factor of Activated T cells (NFAT) system and using PBMCs or jurkat (JKT) del beta/CD8 to identify a shared neoantigen-reactive TCR, comprising the following steps;
(c1) co-culturing a) a reporter T cell comprising a TCR candidate for shared neoantigen expression cassette, and b) an antigen presenting cell (APC) that expresses the shared neoantigen sequence and a human leukocyte antigen (HLA) sequence from the subject with cancer;
wherein the reporter T cell is a jurkat del beta cell; and
wherein the TCR candidate for shared neoantigen expression cassette comprises a TCR candidate sequence reconstructed from TCR α and β chain sequences;
(c2) identifying a positive reporter signal in the reporter T cell to identify the neoantigen-reactive TCR; wherein the shared neoantigen-reactive TCR comprises a sequence selected from the group consisting of SEQ ID NOs:135 to 142.
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