A method for determining a nucleic acid sequence encoding an antibody that interacts with one or more display particles in a sample comprising one or more antibody secreting cells (ASCs) or ASC precursor cells and the nucleic acid sequence of nucleic acid(s) used to identify the antigen(s) that interact with the antibody, the method comprising optionally, subjecting the sample comprising the one or more ASCs or ASC precursor cells to conditions suitable for expansion of the one or more ASCs or ASC precursor cells, to form an expanded sample comprising ASCs; distributing the sample into a plurality of microfluidic chambers to provide a plurality of subsamples, wherein each microfluidic chamber contains a single ASC or ASC precursor cell; optionally, subjecting one or more subsamples to conditions suitable for expansion of the one or more ASCs or ASC precursor cells in the one or more subsamples to form one or more expanded subsamples comprising ASCs; capturing antibodies, present in one or more of the subsamples, on a solid substrate in one or more of the plurality of microfluidic chambers to provide captured antibodies; exposing the captured antibodies in one or more of the microfluidic chambers to an antigen display library comprising a plurality of display particles, for a time sufficient to allow for interaction of the captured antibodies with one or more of the plurality of display particles, wherein each display particle of the plurality of display particles comprises a (poly)peptide-nucleic acid complex, wherein the (poly)peptide is an antigen and the nucleic acid is used to determine the identity of the antigen; capturing one or more display particles that interact with one or more of the antibodies to provide one or more captured display particles; washing the solid substrate to remove unbound display particles; sequencing the nucleic acid encoding the antibody that interacts with one or more of the captured display particles; and sequencing the nucleic acid(s) used to identify the antigen(s) displayed on each on the one or more captured display particles that interacts with the antibody. optionally, subjecting the sample comprising the one or more ASCs or ASC precursor cells to conditions suitable for expansion of the one or more ASCs or ASC precursor cells, to form an expanded sample comprising ASCs; distributing the sample into a plurality of microfluidic chambers to provide a plurality of subsamples, wherein each microfluidic chamber contains a single ASC or ASC precursor cell; optionally, subjecting one or more subsamples to conditions suitable for expansion of the one or more ASCs or ASC precursor cells in the one or more subsamples to form one or more expanded subsamples comprising ASCs; capturing antibodies, present in one or more of the subsamples, on a solid substrate in one or more of the plurality of microfluidic chambers to provide captured antibodies; exposing the captured antibodies in one or more of the microfluidic chambers to an antigen display library comprising a plurality of display particles, for a time sufficient to allow for interaction of the captured antibodies with one or more of the plurality of display particles, wherein each display particle of the plurality of display particles comprises a (poly)peptide-nucleic acid complex, wherein the (poly)peptide is an antigen and the nucleic acid is used to determine the identity of the antigen; capturing one or more display particles that interact with one or more of the antibodies to provide one or more captured display particles; washing the solid substrate to remove unbound display particles; sequencing the nucleic acid encoding the antibody that interacts with one or more of the captured display particles; and sequencing the nucleic acid(s) used to identify the antigen(s) displayed on each on the one or more captured display particles that interacts with the antibody. <EOS>