n. once with RG7420 allergen alone produced a significant amount of IgE (4.5 ± 1.2 ng/mL; mean ± SD; n= 12) and served as a positive control. A small amount of IgE (1.4 ± 0.4 ng/mL; mean ± SD; n= 12) was produced by the mixture of lymphocyte- and macrophage-rich populations from mice that had been treated once i.n. with a mixture of allergen and adjuvant and these served as a negative control. A combination of the lymphocyte-rich population (for IgG production) with the macrophage-rich fraction (for IgE production)

produced a significant amount of IgE (3.3 ± 0.8 ng/mL; mean ± SD; n= 12). In contrast, a combination of the lymphocyte-rich population (for IgE production) with the macrophage-rich fraction (for IgG production) produced a small amount of IgE (1.1 ± 0.5 ng/mL; mean ± SD; n= 12). Similarly, a mixture of cells in the lymphocyte-rich and macrophage-rich populations from mice that had been treated i.n. once with BI 2536 solubility dmso a mixture of allergen and adjuvant produced a large amount of IgG (477.0 ± 135.0 ng/mL; mean ± SD; n= 12) Ab and served as a positive control. A small amount

of IgG (9.4 ± 1.2 ng/mL; mean ± SD; n= 12) was produced by a mixture of lymphocyte- and macrophage-rich populations from mice that had been treated i.n. once with allergen and these served as a negative control. A combination of the lymphocyte-rich population (for IgE production) with the macrophage-rich population (for IgG production) produced a large amount of IgG (359.5 ± 65.0 ng/mL; mean ± SD; n= Megestrol Acetate 12). In contrast, a combination of the lymphocyte-rich fraction (for IgG production) with the macrophage-rich fraction (for IgE production) produced a small amount of IgG (181.6 ± 57.6 ng/mL; mean ± SD; n= 12). These results taken together indicate that cells in the macrophage-rich population are involved in class switching to IgE or IgG after i.n. sensitization by allergen alone or with complete Freund’s adjuvant, respectively. Interleukin-4 is essential for in vitro or in vivo production of nonspecific IgE Abs in lymphocytes after sensitization with cedar

pollen i.n. once (8). Therefore, we assessed the cellular source of IL-4 and its amount in the culture medium (Fig. 9). Bulk submandibular lymph node cells from mice that had been injected once i.n. with allergen alone produced a large amount of IL-4 (96.1 ± 8.6 pg/mL; mean ± SD; n= 9). In contrast, the lymphocyte-rich (fraction 3) fraction of the lymph node cells produced a small amount (31.3 ± 10.9 pg/mL; mean ± SD; n= 9); and the macrophage-rich (fraction 2) fraction was almost inactive (20.1 ± 6.9 pg/mL; mean ± SD; n= 9). Surprisingly, mixed cultures of the lymphocyte-rich fraction with the macrophage-rich fraction produced a large amount of IL-4 (75.3 ± 9.9 pg/mL; mean ± SD; n= 9) that was released into the culture medium (Fig. 9a). In contrast, the amounts of IL-4 produced by cells in the damaged cell (fraction 1; 11.5 ± 2.