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Diesel exhaust particles (DEP) were described as potent adjuvant in the induction and maintenance of allergic diseases, suggesting that they might play a role in the increase of allergic diseases in the industrialized countries. However, the cellular basis by which these particles enhance allergic immune responses is still a matter of debate. Thus, we exposed immature murine bone marrow–derived dendritic cells (BMDC) to different particles or particle-associated organic compounds in the absence or presence of the maturation stimuli lipopolysaccharide (LPS) and analyzed the cellular maturation, viability, and cytokine production. Furthermore, we monitored the functionality of particle-exposed BMDC to suppress B cell isotype switching to immunoglobulin (Ig) E. Only highly polluted DEP (standard reference material 1650a [SRM1650a]) but not particle-associated organic compounds or less polluted DEP from modern diesel engines were able to modulate the dendritic cell phenotype. SRM1650a particles significantly suppressed LPS-induced IL-12p70 production in murine BMDC, whereas cell-surface marker expression was not altered. Furthermore, SRM1650a-exposed immature BMDC lost the ability to suppress IgE isotype switch in B cells. This study revealed that highly polluted DEP not only interfere with dendritic cell maturation but also additionally with dendritic cell function, thus suggesting a role in Th2 immune deviation. [ABSTRACT FROM PUBLISHER]

Background: Primary cellular immunodeficiencies are a group of genetic disorders in which 1 or more components of the cellular immune system are lacking or dysfunctional. Objective: We sought to identify novel mouse mutants that display primary cellular immunodeficiencies. Methods: Genome-wide N-ethyl-N-nitrosourea mutagenesis was performed in mice, followed by a phenotype screen of immunologic blood parameters. Results: We identified novel mouse mutants with isolated B-cell deficiency, combined block in early B- and T-cell development, combined T-cell and natural killer cell reduction, and 3 different forms of T-cell deficiencies. One of the mutants, designated ΔT3, displayed a combined phenotype of increased IgE, absence of peripheral T cells, and block in late thymocyte differentiation. In addition, ΔT3 mice were unable to mount specific humoral immune responses. Chromosomal mapping and sequencing of candidate genes revealed a novel point mutation in the kinase domain of the T-cell receptor ζ chain–associated protein kinase (Zap70). In contrast to Zap70-deficient mice, ΔT3 mutants displayed normal Zap70 mRNA and residual Zap70 protein levels. Complementation studies with Zap70-deficient mice confirmed that the point mutation found in Zap70 was causative for the ΔT3 phenotype, including increased IgE plasma levels, a phenotype that has not been associated with altered Zap70 function in the past. Conclusion: Random genome-wide mutagenesis combined with a phenotype screen can be used to generate novel mouse mutants with primary cellular immunodeficiencies. [Copyright &y& Elsevier]

Abstract: Anti-IgE therapeutics represent an efficient approach in the management of IgE-mediated allergic asthma. However, monitoring the reduction of IgE levels into a therapeutically efficient range requires the determination of residual serum IgE. We established an analytical approach to distinguish free and anti-IgE complexed serum IgE based on soluble derivatives of the human high-affinity IgE receptor. Soluble receptor derivatives represent an ideal means to analyze receptor antagonism by any ligand or blocking antibody. Therefore, the FcεRI ectodomain was fused with avian IgY constant domains that circumvent susceptibility to interference phenomena and improve assay performance. After production in HEK293 cells, subsequent characterization by enzyme-linked immunosorbent assay and immunoblotting confirmed the suitability of avian IgY constant domains for immobilization and detection purposes. To provide further insights into the different IgE reactivities, free allergen-specific IgE was also determined. Monitoring of sera from omalizumab-treated patients during the course of therapy revealed the applicability for assessment of omalizumab-complexed versus noncomplexed serum IgE. These parameters may allow correlation to clinical responses during anti-IgE therapy with the perspective of biomonitoring. [Copyright &y& Elsevier]