Long-lasting immune responses 4 years after GAD-alum treatment in children with type 1 diabetes

PLoS One. 2011;6(12):e29008. doi: 10.1371/journal.pone.0029008. Epub 2011 Dec 12.


A phase II clinical trial with glutamic acid decarboxylase (GAD) 65 formulated with aluminium hydroxide (GAD-alum) has shown efficacy in preserving residual insulin secretion in children and adolescents with recent-onset type 1 diabetes (T1D). We have performed a 4-year follow-up study of 59 of the original 70 patients to investigate long-term cellular and humoral immune responses after GAD-alum-treatment. Peripheral blood mononuclear cells (PBMC) were stimulated in vitro with GAD(65). Frequencies of naïve, central and effector memory CD4+ and CD8+ T cells were measured, together with cytokine secretion, proliferation, gene expression and serum GAD(65) autoantibody (GADA) levels. We here show that GAD-alum-treated patients display increased memory T-cell frequencies and prompt T-cell activation upon in vitro stimulation with GAD(65), but not with control antigens, compared with placebo subjects. GAD(65)-induced T-cell activation was accompanied by secretion of T helper (Th) 1, Th2 and T regulatory cytokines and by induction of T-cell inhibitory pathways. Moreover, post-treatment serum GADA titres remained persistently increased in the GAD-alum arm, but did not inhibit GAD(65) enzymatic activity. In conclusion, memory T- and B-cell responses persist 4 years after GAD-alum-treatment. In parallel to a GAD(65)-induced T-cell activation, our results show induction of T-cell inhibitory pathways important for regulating the GAD(65) immunity.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Aluminum Hydroxide / blood
  • Aluminum Hydroxide / pharmacology
  • Aluminum Hydroxide / therapeutic use*
  • CD4-Positive T-Lymphocytes / cytology
  • CD4-Positive T-Lymphocytes / drug effects
  • CD4-Positive T-Lymphocytes / immunology
  • CD4-Positive T-Lymphocytes / metabolism
  • CD8-Positive T-Lymphocytes / cytology
  • CD8-Positive T-Lymphocytes / drug effects
  • CD8-Positive T-Lymphocytes / immunology
  • CD8-Positive T-Lymphocytes / metabolism
  • Cell Proliferation / drug effects
  • Child
  • Cytokines / metabolism
  • Diabetes Mellitus, Type 1 / blood
  • Diabetes Mellitus, Type 1 / drug therapy*
  • Diabetes Mellitus, Type 1 / immunology*
  • Gene Expression Regulation / drug effects
  • Glutamate Decarboxylase / blood
  • Glutamate Decarboxylase / pharmacology
  • Glutamate Decarboxylase / therapeutic use*
  • Humans
  • Immunity / drug effects
  • Immunity / immunology*
  • Immunologic Memory / drug effects
  • Lymphocyte Activation / drug effects
  • Lymphocyte Activation / immunology
  • Lymphocyte Count
  • Real-Time Polymerase Chain Reaction


  • Cytokines
  • Aluminum Hydroxide
  • Glutamate Decarboxylase