Determining antigen-specific T-cells
The invention is directed to methods for determining antigen-specific T cells. In some embodiments, methods of the invention may be implemented by the steps of reacting under interaction conditions one or more antigens with T cells in a plurality of subsets of a tissue sample, such as peripheral blood; sorting antigen-interacting T cells from other T cells; separately sequencing for each subset recombined nucleic acid encoding a segment of a TCR chain from a sample of T cells prior to exposure to antigen and from a sample of T cells isolated based on their interaction with antigen, thereby forming a clonotype profile for the former sample and the latter sample for each subset; and identifying as antigen-specific T cells those T cells associated with a clonotype whose frequency increases in the latter sample relative to its frequency in the former sample.
1. A method for determining the sequence of one or more T-cell receptor (TCR) chain(s) or a portion thereof specific for one or more antigens of interest in a sample comprising T cells specific for a plurality of antigens, the method comprising the steps of:
(a) sequencing recombined nucleic acids encoding one or more TCR chain(s) or a portion thereof from a first portion of the sample to generate a first plurality of sequence reads obtained from T cells prior to antigen exposure of the sample, wherein the sequencing is high-throughput sequencing;
(b) partitioning a second portion of the sample comprising T cells into a plurality of reaction mixtures and exposing each reaction mixture of the plurality of reaction mixtures to a plurality of antigens, wherein each antigen of said plurality of antigens is presented by antigen presenting cells in a unique and predetermined subplurality of the plurality of reaction mixtures;
(c) for each reaction mixture in the plurality of reaction mixtures, separating T cells that interact with one or more antigens in the plurality of antigens from the reaction mixture to obtain a subset of antigen-specific T cells, wherein each of the subsets of antigen-specific T cells corresponds to one reaction mixture in the plurality of reaction mixtures;
(d) for each of the subsets of antigen-specific T cells separated in step (c), sequencing recombined nucleic acids encoding one or more TCR chain(s) or a portion thereof to generate a plurality of sequence reads obtained from each of the subsets of antigen-specific T cells, wherein the sequencing is high-throughput sequencing;
(e) for each reaction mixture in the plurality of reaction mixtures, identifying a plurality of antigen-specific TCR chains by comparing the plurality of sequence reads obtained from each of the subsets of antigen-specific T cells in step (d) to the first plurality of sequence reads obtained from unstimulated T cells in step (a),
wherein the frequency of the sequence reads for the antigen-specific TCR chains is increased in the plurality of sequence reads obtained from the subsets of antigen-specific T cells compared to the frequency of sequence reads for the antigen-specific TCR chains in the first plurality of sequence reads obtained from unstimulated T cells; and
(f) for each of the one or more antigens of interest, identifying one or more TCR chains specific for the antigen of interest from the one or more TCR chains identified in step (e), wherein the frequency of the sequence reads for the one or more TCR chains specific for the antigen of interest is increased in the plurality of sequence reads obtained from each of the subsets of antigen-specific T cells in which the antigen of interest was present in the corresponding reaction mixture.
2. The method of claim 1 wherein the high throughput sequencing includes isolating individual molecules of said recombined nucleic acids on a solid surface and sequencing the isolated individual molecules to provide said sequence reads.
3. The method of claim 2 , further comprising coalescing the plurality of sequence reads obtained from the subsets of antigen-specific T cells to identify each of said antigen-specific TCR chains or portions thereof.
4. The method of claim 1 wherein said step of separating is implemented with an antigen reagent capable of forming a complex with one or more T cells specific for one or more of the plurality of antigens or a binding compound specific for an activation marker present on one or more T cells specific for one or more of the plurality of antigens.
5. The method of claim 4 wherein said antigen reagent is a peptide-MHC multimer complex wherein the peptide of the complex is derived from said antigen of interest.
6. The method of claim 1 wherein said sample comprises peripheral blood or is derived from peripheral blood.
7. The method of claim 1 wherein the number of antigens present in the plurality of antigens is between 2 to 1000 antigens.
8. The method of claim 1 , wherein the number of antigen present in the plurality of antigens is at least 4.