A method for nucleic acid sequencing, comprising: (a) providing a plurality of partitions, wherein a partition of said plurality of partitions comprises (i) a ribonucleic acid (RNA) molecule from an immune cell, wherein the RNA molecule comprises a nucleic acid sequence of a T cell receptor or a B cell receptor, and (ii) a bead comprising a nucleic acid barcode molecule coupled thereto, wherein said nucleic acid barcode molecule comprises a barcode sequence and a primer sequence; (b) using said RNA molecule and said nucleic acid barcode molecule to generate a barcoded nucleic acid molecule comprising, from a 5' end to a 3' end, said barcode sequence and a sequence corresponding to said nucleic acid sequence of said RNA molecule, wherein the generating comprises (i) hybridizing said nucleic acid barcode molecule to said RNA molecule, (ii) extending said nucleic acid barcode molecule using a reverse transcriptase having terminal transferase activity to generate a nucleic acid product comprising a reverse complement of a sequence of said RNA molecule and a sequence at its 3' end that is complementary to a portion of a template switching oligonucleotide, (iii) hybridizing said nucleic acid product to said template switching oligonucleotide, and (iv) extending said nucleic acid product using said template switching oligonucleotide as a template; (c) using said barcoded nucleic acid molecules, or a derivative thereof, and a pair of primers to generate a subset of nucleic acids having a TCR or BCR target nucleic acid sequence to provide an enriched subset of barcoded nucleic acid molecules or derivatives thereof; and (d) sequencing said enriched subset of barcoded nucleic acid molecules, or derivatives thereof, and an unenriched subset of barcoded nucleic acid molecules, or derivatives thereof. (a) providing a plurality of partitions, wherein a partition of said plurality of partitions comprises (i) a ribonucleic acid (RNA) molecule from an immune cell, wherein the RNA molecule comprises a nucleic acid sequence of a T cell receptor or a B cell receptor, and (ii) a bead comprising a nucleic acid barcode molecule coupled thereto, wherein said nucleic acid barcode molecule comprises a barcode sequence and a primer sequence; (b) using said RNA molecule and said nucleic acid barcode molecule to generate a barcoded nucleic acid molecule comprising, from a 5' end to a 3' end, said barcode sequence and a sequence corresponding to said nucleic acid sequence of said RNA molecule, wherein the generating comprises (i) hybridizing said nucleic acid barcode molecule to said RNA molecule, (ii) extending said nucleic acid barcode molecule using a reverse transcriptase having terminal transferase activity to generate a nucleic acid product comprising a reverse complement of a sequence of said RNA molecule and a sequence at its 3' end that is complementary to a portion of a template switching oligonucleotide, (iii) hybridizing said nucleic acid product to said template switching oligonucleotide, and (iv) extending said nucleic acid product using said template switching oligonucleotide as a template; (c) using said barcoded nucleic acid molecules, or a derivative thereof, and a pair of primers to generate a subset of nucleic acids having a TCR or BCR target nucleic acid sequence to provide an enriched subset of barcoded nucleic acid molecules or derivatives thereof; and (d) sequencing said enriched subset of barcoded nucleic acid molecules, or derivatives thereof, and an unenriched subset of barcoded nucleic acid molecules, or derivatives thereof. <EOS>