In previous studies, we observed that normal mice transferred with 5×106 splenocytes from diabetic mice by multiple low dose of streptozotocin-(Model 1, Ml)-showed anti-beta cell immune aggression(Im. Aggr.)at 7 and 15 days after cell injection and inhibition of both phases of glucose-stimulated insulin sccretion(I.S. × gl.) only at day 15. On the other hand, mice transferred with 2×106, 2×106 and splenocytes every 48hs-Modol 2(M2)-showed Im.Aggr. at 7 and 15 days after transfer, but no alteration of the I.S.× gl. even 40 days after cell injection. In the present report we studied if Im. Aggr. modulation in M2 could induce alterations in the I.S × gl. Anti-beta cell Im.Aggr. was evaluated by the glucose theophylline stimulated I.S. from dispersed rat islet cells. A single dose of 40mg streptozotocin injected 15 days before(M3) or after (M4) the splenocytes transfer, increased, in the receptor mice, the anti-beta cell Im.Aggr. (p 0.01) only when injected 15 days before, but induced inhibition of the first phase I.S.× 1g (p 0.05), in both cases, at day 15 post-transfer. The injection of 5×106 diabetic splenocytes(M1), 15 days after M3 transfer, increased the Im.Aggr. (p 0.01) but not the inhibition of I.S.× gl. The modulation of Im.Aggr. intensity and frequency seems to be a main factor in the beta cell function observed in the receptor mice.