Assess T Cell Responses

The Naïve Donor T cell Assay (or In Vitro Immunization Protocol, “IVIP”, Assay) tests the relative immunogenicity of sequences in freshly sourced PBMC samples derived from healthy human blood donors to closely mimic a natural, naïve human T cell immune response to a potential antigen. The PBMC samples are HLA-typed in order to ensure coverage of prevalent HLA types in the assessment.

PBMC samples are cultured with the test article or relevant controls for a number of days before being transferred to a FluoroSpot assay where PBMCs are stimulated as either a rechallenge or first exposure with the appropriate test article or control. The FluoroSpot assay is developed with fluorescently labeled anti-cytokine antibodies, enabling the quantification of adaptive immune cytokine-producing cells. Positive responses are determined by comparing cytokine readouts to the exposed and unexposed samples to assess T cell activation of cell type-specific effector cells.

The T cell Assay is useful for assessing the immunogenicity of peptides. This is relevant to comparing immunogenic potential of generic peptide APIs and associated impurities and to validate any putative T cell epitope “hotspots” that might be identified in biologic therapeutic or vaccine candidate sequences through in silico analysis.