PERIPHERAL T-CELL CLONES FROM NOD MICE SPECIFIC FOR GAD65 PEPTIDES - LACK OF ISLET RESPONSIVENESS OR DIABETOGENICITY

The non-obese diabetic (NOD) mouse develops diabetes as a result of sp ontaneous T cell mediated destruction of the insulin-producing beta-ce lls. Tolerization to glutamic acid decarboxylase (GAD65) has been repo rted to inhibit spontaneous T eel proliferative responses to GAD65 and GAD65 peptides and prevent insulitis and diabetes in NOD mice. To eva luate the role of T cells responsive to GAD65 in induction of diabetes in NOD mice we generated T cell clones from spleen cells of three pre diabetic NOD mice using the reported immunodominant human GAD65 peptid es nos. 17, 34 and 35, which are spontaneously recognized by NOD splee n cells. The ten T cell clones established from two female and one mal e NOD mice recognized either the GAD65 peptide no. 35 which has an ide ntical amino acid sequence in mice and humans or recognized the human GAD65 peptide no. 17 which is different in two amino acids from murine GAD65 peptide no, 17. None of the clones exhibited responses to islet cells, and GAD65 peptide no. 17 responsive clones did not cross react with the murine GAD65 peptide no. 17. All clones were CD4 positive an d expressed the alpha/beta T cell receptor, but differed in their V be ta usage. Analysis of in vitro production of IFN gamma, IL-2 and IL-4 demonstrated a TH1 and TH0 like functional subset of the individual cl ones. In vivo, neither the autoreactive T cell clones specific for GAD 65 peptide no. 35 nor the xenoreactive clones specific for GAD65 pepti de no. 17 were able to accelerate diabetes in young NOD mice or transf er diabetes into NODscid mice. (C) 1996 Academic Press Limited