The present invention describes novel methods to generate MHC multimers and methods to improve existing and new MHC multimers. The invention also describes improved methods for the use of MHC multimers in analysis of T-cells in samples including diagnostic and prognostic methods. Furthermore the use of MHC multimers in therapy are described, e.g. anti-tumour and anti-virus therapy, including isolation of antigen specific T-cells capable of inactivation or elimination of undesirable targeT-cells or isolation of specific T-cells capable of regulation of other immune cells.