A method of selecting an analyte engineered antigen-presenting cell or a T-cell receptor of an analyte engineered antigen-presenting cell T-cell receptor (eAPC:T) system, wherein the eAPC:T system comprises an analyte engineered antigen-presenting cell (eAPC) and an analyte T-cell receptor (analyte TCR), wherein the eAPC is a cell that lacks endogenous expression of one or more of a target antigen-presenting complex (aAPX) and/or analyte antigenic molecule (aAM), wherein the eAPC comprises a genomic receiver site for integration of an open reading frame encoding the analyte antigen, the method comprising: a first step of combining the eAPC with a genetic donor vector coupled with said genomic receiver site, such that the genetic donor vector integrates into the genomic receiver site at least one ORF encoding at least one aAPX and/or aAM and a second step comprising: (a) i) Combining one or more analyte eAPC with one or more analyte TCR, resulting in a contact between an analyte antigen presented by the analyte eAPC with analyte TCR (b) ii) measuring a formation, if any, of a complex between one or more analyte antigen with one or more analyte TCR and/or iii) measuring a signal from a labelled analyte TCR and/or iv) measuring a signal response by the analyte eAPC, if any, induced by the formation of a complex between one or more analyte antigen with one or more analyte TCR(s) and/or v) measuring a signal response in an analyte TCR-presenting cell, if any, induced by the formation of a complex between one or more analyte antigen(s) with one or more analyte TCR(s) and (c) vi) Selecting one or more analyte eAPC or analyte TCR based on step ii, iii, iv /or v wherein the selection is made by a positive and/or negative measurement. a first step of combining the eAPC with a genetic donor vector coupled with said genomic receiver site, such that the genetic donor vector integrates into the genomic receiver site at least one ORF encoding at least one aAPX and/or aAM and a second step comprising: (a) i) Combining one or more analyte eAPC with one or more analyte TCR, resulting in a contact between an analyte antigen presented by the analyte eAPC with analyte TCR (b) ii) measuring a formation, if any, of a complex between one or more analyte antigen with one or more analyte TCR and/or iii) measuring a signal from a labelled analyte TCR and/or iv) measuring a signal response by the analyte eAPC, if any, induced by the formation of a complex between one or more analyte antigen with one or more analyte TCR(s) and/or v) measuring a signal response in an analyte TCR-presenting cell, if any, induced by the formation of a complex between one or more analyte antigen(s) with one or more analyte TCR(s) and (c) vi) Selecting one or more analyte eAPC or analyte TCR based on step ii, iii, iv /or v wherein the selection is made by a positive and/or negative measurement. (a) i) Combining one or more analyte eAPC with one or more analyte TCR, resulting in a contact between an analyte antigen presented by the analyte eAPC with analyte TCR (b) ii) measuring a formation, if any, of a complex between one or more analyte antigen with one or more analyte TCR and/or iii) measuring a signal from a labelled analyte TCR and/or iv) measuring a signal response by the analyte eAPC, if any, induced by the formation of a complex between one or more analyte antigen with one or more analyte TCR(s) and/or v) measuring a signal response in an analyte TCR-presenting cell, if any, induced by the formation of a complex between one or more analyte antigen(s) with one or more analyte TCR(s) and iii) measuring a signal from a labelled analyte TCR and/or iv) measuring a signal response by the analyte eAPC, if any, induced by the formation of a complex between one or more analyte antigen with one or more analyte TCR(s) and/or (c) vi) Selecting one or more analyte eAPC or analyte TCR based on step ii, iii, iv /or v wherein the selection is made by a positive and/or negative measurement.