Abstract: Proto-antigen-presenting surfaces and related kits, methods, and uses are provided. The proto-antigen-presenting surface can comprise a plurality of primary activating molecular ligands comprising a major histocompatibility complex (MHC) molecule configured to bind to a T cell receptor (TCR) of a T cell and a plurality of co-activating molecular ligands each including a TCR co-activating molecule or an adjunct TCR activating molecule, wherein an exchange factor is bound to the MHC molecules. Exchange factors include, e.g., dipeptides such as GL, GF, GR, etc. Proto-antigen-presenting surfaces can be used to rapidly prepare antigen-presenting surfaces comprising one or more peptide antigens of interest by contacting the proto-antigen-presenting surface with one or more peptide antigens so as to displace the exchange factor. As such, the disclosure facilitates rapid evaluation of the immunogenicity of peptide antigens for activating T lymphocytes.

Abstract: Methods are provided for the assay of secreted biomolecules using automated detection and characterization of micro-objects in a microfluidic device. The biomolecules can be secreted by cells, particularly immunological cells, such as T cells. The biomolecules being assayed can include cytokines, growth factors, and the like. Methods are also provided for assaying the cytotoxicity of a cell with respect to another, target cell. Also provided are kits and non-transitory computer-readable media in which programs are stored for causing a system comprising a computer to perform automated methods for detecting secreted biomolecules and/or cytotoxicity in a microfluidic device.

Abstract: In biosciences and related fields, it can be useful to modify surfaces of apparatuses, devices, and materials that contact biomaterials such as biomolecules and biological micro-objects. Described herein are surface modifying and surface functionalizing reagents, preparation thereof, and methods for modifying surfaces to activate T Lymphocytes.

Abstract: Proto-antigen-presenting surfaces and related kits, methods, and uses are provided. The proto-antigen-presenting surface can comprise a plurality of primary activating molecular ligands comprising a major histocompatibility complex (MHC) molecule configured to bind to a T cell receptor (TCR) of a T cell and a plurality of of co-activating molecular ligands each including a TCR co-activating molecule or an adjunct TCR activating molecule, wherein an exchange factor is bound to the MHC molecules. Exchange factors include, e.g., dipeptides such as GL, GF, GR, etc. Proto-antigen-presenting surfaces can be used to rapidly prepare antigen-presenting surfaces comprising one or more peptide antigens of interest by contacting the proto-antigen-presenting surface with one or more peptide antigens so as to displace the exchange factor. As such, the disclosure facilitates rapid evaluation of the immunogenicity of peptide antigens for activating T lymphocytes.