The present invention provides a method for identifying a single or group of T cell receptors (TCR) protective and/or effective against a disease, having the following steps: i) obtaining T cells from a donor non-human animal; ii) adoptive transfer of the T cells into a plurality of T cell-deficient recipient non-human animals in a number such that at least one recipient animal is protected against the disease but at least one animal remains unprotected; and iii) determination of the TCR(s) present only in the protected animals. These TCR can be used to identify the determinants or antigens for inclusion in a vaccine or other treatment.