Human IgE in severe combined immunodeficiency mice reconstituted with peripheral blood mononuclear cells from Dermatophagoides pteronyssinus-sensitive patients.

We studied conditions of human IgE formation in severe combined immunodeficiency (SCID) mice engrafted with peripheral blood mononuclear cells (PBMCs) from allergic patients sensitive to Dermatophagoides pteronyssinus (D.pt.). With 10 x 10(6) PBMCs injected intraperitoneally, the hu-SCID mice developed an IgE response, but only if experimental animals were immunized with the related allergen. Two routes of immunization were tested: intraperitoneal and inhalation. In these experimental conditions (allergen given at day 14 after reconstitution), a significant rise in total serum IgE but also in specific anti-D.pt. IgE was observed. No human IgE could be detected within 3-4 weeks after immunization with an unrelated allergen. Similarly, when mice were engrafted with PBMCs from nonallergic donors, even after D.pt. administration, no significant increase of serum IgE was detectable, while an IgG response was regularly found. Thus SCID mice could represent a useful model to analyze IgE production as well as the conditions of immunization required to obtain an optimal response.