Reliable and sensitive detection of
antigen specific cells is essential in several fields of research, whether it concerns monitoring responses to infectious agents or exploring the auto-
antigen repertoire in
autoimmune diseases. Identification of these cells is however difficult, especially when the cells often are rare and methods not sensitive, specific or practical enough. We propose a novel method of processing
antigens before stimulation of cells which consists of covalently
binding protein antigen to superparamagnetic micro-beads and using denaturing washes to remove contaminants. Peripheral blood mononuclear cells (PBMCs) from healthy donors were stimulated using both cytomegalovirus and
tetanus-
diphtheria antigen-beads as well as non-antigenic
protein-beads as negative control in an IFNγ FluoroSpot assay in order to detect Th1 and CD8+ responses. The responses toward the
antigen beads were both
antigen specific and sensitive, with a detection threshold of 1 IFNγ producing T-cell per 18,000 PBMCs. •Covalently binding
antigen to paramagnetic beads allows for harsh denaturing washes without loss of
antigen.•Microbeads are phagocytosed by antigen presenting cells, resulting in efficient uptake, processing and presentation of the
antigens.•The method allows the usage of relatively impure starting
antigen material and whole PBMC samples without high background levels in follow up cellular assays.