The generation of monoclonal antibodies by genetic immunisation: antibodies against trout TCRα and IgL isotypes

Production of monoclonal antibodies (mAb) using genetic immunisation is a potential alternative when purified antigen is difficult to obtain, or when induction of an antibody response to a limited part of an antigen is wanted. DNA immunisation using only the constant parts of trout immunoglobulin light chains coding regions was attempted here, because mAbs against the variable (V) part of immunoglobulins do not recognise the whole repertoire of the isotype. After positive results with the light chains and establishing of a proper screening system (ELISA), generation of monoclonal antibodies against trout T cell receptor was also performed. A constructs were used both for immunisation of mice and for protein expression in EBNA 293 cells. Mice were immunised with the constructs 3–5 times by intramuscular injection, with or without adjuvants during 1–3 months. Spleens of positive mice were fused with myeloma Sp2/0 cells and clones were screened by ELISA using double-screening (recombinant protein/trout cells). 6E5 (anti-IgL2C), 4F2 (anti-TCRα), 18B3 (anti-TCRαC) and 4E5 (anti-TCRαC) show specific binding to its antigen in Western blot, mAb 18B3 and 7H7(anti-TCRα) shows specific staining of trout splenocytes in flow cytometry and mAb 7H7 induces proliferation of trout peripheral blood leucocytes (PBL) in vitro.