Study design and exposure scheme. Mice were sensitized intranasally (IN) on days 1, 3, 6 and 8 with 0.02% OVA or saline (SAL). SNP were co-administered at intranasal doses of 0, 10, 100, or 400 μg with OVA or saline. On days 22 and 23, OVA-mice were challenged intranasally with 0.5% OVA and SAL-mice with saline solution. Animals were sacrificed on day 24, 24 hours after the last intranasal challenge.