Prolongation of the responsiveness of newborn mice to syngeneic IgE by inhibition of IgE synthesis.

Between the ages of 2 to approximately 11 days mice respond to a challenge with syngeneic IgE by producing anti-IgE antibodies; by the age of 2 weeks they are unresponsive. Even adult mice, however, produce high titers of anti-IgE antibodies when immunized with a conjugate of syngeneic IgE and a foreign antigen such as keyhole limpet hemocyanin (KLH), indicating that adult tolerance to unconjugated IgE resides in the T-cell compartment. The loss of responsiveness in 2-week-old mice follows closely after the first appearance of IgE-secreting cells and detectable serum IgE. This suggests that the delayed onset of tolerance is attributable to the delay in synthesis of IgE. Data presented here provide support for this hypothesis. A further delay in the initial synthesis of IgE, induced by neonatal administration of anti-IgM antibodies, caused a corresponding extension of the period after birth during which mice remain responsive to unconjugated IgE.