Increased expression of type 2 cytokines in chronic proliferative dermatitis (cpdm) mutant mice and resolution of inflammation following treatment with IL-12

Chronic proliferative dermatitis (cpdm) is a spontaneous mutation that results in eosinophilic inflammation in multiple tissues, including the skin. To determine the mechanisms underlying the eosinophilic inflammation, the expression of cytokines in the skin was determined. There was increased expression of IL-4, IL-5, IL-13, and granulocyte-macrophage colony-stimulating factor in the skin of cpdm/cpdm mice, and no change in IL-10 and TNF expression. Supernatants of cultured spleen cells of cpdm/cpdm mice contained an increased amount of IL-5 and IL-13, and a decreased amount of IFN-gamma. The ability of the cpdm/cpdm mice to mount a delayed-type hypersensitivity response was greatly reduced. These data are consistent with impaired type 1 and excessive type 2 cytokine production in cpdm/cpdm mice. The significance of this imbalanced cytokine production was evident in the efficacy of systemic treatment of cpdm/cpdm mice with IL-12. Mutant mice treated for 3 weeks with IL-12 had minimal changes in the skin as opposed to the severe dermatitis in mice treated with the vehicle. Treatment with IL-11, which opposes the effect of IL-12, had no effect.

Systemic and pulmonary immune response to intrabronchial administration of ovalbumin in calves

Local immunization of the respiratory tract may be the best way to achieve protection against respiratory pathogens. In order to do so successfully, it is important to fully understand how the immune response to antigen administered via the respiratory route develops. We studied the respiratory and systemic immune response after subcutaneous (SC) and intrabronchial (IB) inoculation of calves with ovalbumin (OVA). Eight calves received two SC inoculations of OVA and eight other calves received two SC and three additional IB inoculations of OVA. The occurrence of OVA-specific antibodies and antibody-secreting cells (ASC) was measured over time using isotype-specific enzyme linked immunosorbent assay (ELISA) and ELISPOT. SC immunization of calves did not result in OVA-specific IgA in bronchoalveolar lavage (BAL) fluid. Subcutaneous priming followed by intrabronchial challenge caused an initial IgG1 response in the bronchoalveolar lavage fluid, followed by a large IgA response. The presence of IgG1-ASCs indicated that the IgG1 was at least partially locally produced. Most of the OVA-specific IgA in the BAL fluid was secreted by pulmonary ASCs as indicated by the large number of IgA-ASCs in BAL samples and the low serum level of OVA-specific IgA. Antigen-specific IgG1 ASCs were detectable among peripheral mononuclear cells after culture with OVA.