Stable expresion in a CHO cell line of the autoantigen IA-2ic involved in Autoimmune Diabetes Mellitus

TRABUCCHI, ALDANA; VILLALBA, ANABEL; VALDEZ, SILVINA N.; SICA, MAURICIO P.; POSKUS, EDGARDO; IACONO, RUBEN F.

Rio de Janeiro, Brasil

Congreso; 13th International Congress of Immunology; 2007

One of the major autoantigens involved in autoimmune diabetes mellitus (DM) is the Insulinoma Associated, IA-2, tyrosine phosphatase. Nearby 65-70% of patients with recent onset of Type 1 DM present autoantibodies against the intra-cellular fragment of this protein (IA-2ic). Since it is well known that in some recent-onset type 1 diabetic patients serum IA-2 antibodies (IA-2A marker) are not detected by the conventional method, the aim of the study was to express the recombinant autoantigen IA-2ic in CHO cells, to characterize immunoreactivity of sera from patients with autoimmune DM and compare these results with those obtained with the reference method (RBA) that involves the use of radiolabeled soluble antigen. CHOk1 cells were transfected with the cDNA coding for IA-2ic cloned in the pCI-neo vector. Nowadays we dispose of a stable cell line expressing recombinant IA-2ic. The synthesis of such protein was evaluated by Western blot and indirect immunofluorescence (IIF) using a polyclonal serum to IA-2ic. The Western blot disclosed a 43 kDa band compatible with IA-2ic and IIF displayed a specific immunoreactivity.