Provided herein are methods that enable parallel evaluation of multiple functional nucleic acids in individual cells or subpopulations of cells, in the context of incubation with other types of single cells. The key insight is concurrent measurement of polynucleic acids derived from small populations of at least two different cell types, such that function in one cell type is linked to the clonal identity of another cell. These methods simultaneously process thousands, millions, or more single cells or small populations of cells. The method integrates molecular, algorithmic, and engineering approaches. This invention has broad and useful application in a number of biological and medical fields, including immunology and drug discovery.

Disclosed in the present application is a method for constructing an antigen-specific binding polypeptide gene display vector. The method comprises processing by using a restriction endonuclease that specifically recognizes a restriction site to obtain four nucleic acid fragments having specific sticky ends, and then enabling the nucleic acid fragments to directionally ligate. Further disclosed in the present application are an antigen-specific binding polypeptide gene display vector produced according to the method and a bacterial library. The method described in the present application can be used for effectively screening antigen-specific antigen-binding polypeptides or fragments thereof.

Disclosed in the present application is a method for constructing an antigen-specific binding polypeptide gene display vector. The method comprises processing by using a restriction endonuclease that specifically recognizes a restriction site to obtain four nucleic acid fragments having specific sticky ends, and then enabling the nucleic acid fragments to directionally ligate. Further disclosed in the present application are an antigen-specific binding polypeptide gene display vector produced according to the method and a bacterial library. The method described in the present application can be used for effectively screening antigen-specific antigen-binding polypeptides or fragments thereof.

Described herein are methods, uses, and kits for droplet-based single cell sequencing of nucleic acids from extracellular vesicles. Specifically, the disclosure provides methods of analyzing protein compositions from individual extracellular vesicles (EVs) from biological samples including pluralities of EVs, the methods comprising labeling the EVs with antibody-DNA conjugates; encapsulating the labeled EVs, barcoded beads, and an extension reagent mix into droplets; within one or more of the droplets, hybridizing the antibody-DNA conjugates with a hybridization region in the barcoded beads; generating RNA from the DNA; synthesizing cDNA from the RNA; amplifying and sequencing the cDNA from one or more individual EVs from the biological sample; and analyzing the sequence of the cDNA from individual EVs to define their protein composition.

Described herein are methods, uses, and kits for droplet-based single cell sequencing of nucleic acids from extracellular vesicles. Specifically, the disclosure provides methods of analyzing protein compositions from individual extracellular vesicles (EVs) from biological samples including pluralities of EVs, the methods comprising labeling the EVs with antibody-DNA conjugates; encapsulating the labeled EVs, barcoded beads, and an extension reagent mix into droplets; within one or more of the droplets, hybridizing the antibody-DNA conjugates with a hybridization region in the barcoded beads; generating RNA from the DNA; synthesizing cDNA from the RNA; amplifying and sequencing the cDNA from one or more individual EVs from the biological sample; and analyzing the sequence of the cDNA from individual EVs to define their protein composition.

Provided are methods and compositions for the production of novel antibodies that bind specifically to a target antigen. These methods and compositions are particularly useful for producing antibodies having the antigen binding specificity of a reference antibody but with improved properties (e.g., binding affinity, immunogenicity, and thermodynamic stability) relative to the reference antibody.

Provided are methods for efficiently and comprehensively screening antibody repertoires from B cells to obtain and produce molecules with binding characteristics and functional activities for use in human therapy.

Provided are methods for efficiently and comprehensively screening antibody repertoires from B cells to obtain and produce molecules with binding characteristics and functional activities for use in human therapy.

The present invention relates to a composition for screening various signal peptides to select specific ones that allow efficient secretion of a target protein to out of host cells. The present invention also relates to a method for selecting specific signal peptides that express a target protein in host cells and efficiently secrete the target protein to out of the host cells. The use of the composition and/or method according to the present invention enables ultrafast selection of optimal signal peptides for a target protein through barcoding sequences corresponding to the signal peptides, leading to the maximization of the production yield of the recombinant protein.

The present invention relates to a composition for screening various signal peptides to select specific ones that allow efficient secretion of a target protein to out of host cells. The present invention also relates to a method for selecting specific signal peptides that express a target protein in host cells and efficiently secrete the target protein to out of the host cells. The use of the composition and/or method according to the present invention enables ultrafast selection of optimal signal peptides for a target protein through barcoding sequences corresponding to the signal peptides, leading to the maximization of the production yield of the recombinant protein.