Antigen-specific IgE production

Mast cells can be activated by a variety of stimuli, such as neuropeptides and anaphylo-toxin. In the context of helminth infection, mast-cell activation is accomplished by antigen cross-linkage of IgE bound to the high-affinity Feel receptor. However, antigen-specific IgE production takes 8-10 days after initial antigen exposure and is dependent on T cell-B cell interaction - an adaptive immune response. 

Murosaki, S., Yamomoto, Y., Ito, K., Inokuchi, T., Kusaka, H., and Ikeda, H. 1998. Heat-killed Lactobacillus plantarum L-137 suppresses naturally fed antigen-specific IgE production by stimulation of IL-12 production in mice. J Allergy Clin Immunol 102 57-64. 

Choi CY, Nakajima-Adachi H, Kaminogawa S, Sugita-Konishi Y (2000) Nivalenol inhibits total and antigen-specific IgE production in mice. Toxicol Appl Pharmacol 165 94... 

Fujimaki, H., et al., Inhalation of diesel exhaust enhances antigen-specific IgE antibody production in mice, Toxicology. 116, 1-3, 227, 1997. 

The ability of LAB diet enhanced IFN production to regulate the Thl/Th2 responses has been thoroughly studied in animal models. Feeding OVA-primed mice with L. casei has been shown to reduce antigen-specific IgE responses in vivo (Yasui et al. 1999). A murine model of food allergy has also demonstrated that intraperito-neal administration of L. plantarum can downregulate casein-specific IgE antibody levels in vivo and IL-4 secretion as well (Murosaki et al. 1998). 

FIGURE 93-1. Allergen sensitization and the allergic response. A. Exposure to antigen stimulates IgE production and sensitization of mast cells with antigen-specific IgE antibodies. B. Subsequent exposure to the same antigen produces an allergic reaction when mast cell mediators are released. 

Initial studies in animals have also shown that diesel exhaust particles have an adjuvant effeet on IgE produetion. Mice immunized intraperitoneally with ovalbumin mixed with DEP had increased antigen-specific IgE antibody compared with miee that received ovalbumin alone (88). When antigen and DEP were administered into the nostrils of mice, antigen-specific IgE in the serum was dramatically enhanced compared with levels in control mice receiving ovalbumin alone (89). In a similar fashion, intratracheal instillation of DEP and ovalbumin enhanced lymphocyte proliferation and IL-4 production in the mediastinal lymph nodes 4-17 times control levels, and this effect was associated with increased serum IgE antibody (90). In a study from our laboratory. Brown Norway rats. 

Compared to people in a noncontaminated area, plasma IgG levels were also significantly decreased in proportion to increasing plasma levels of TCDD in a cohort exposed in an industrial accident in Seveso, Italy.118 There was no effect on IgM or IgA levels, or on complement levels IgE was not measured. In separate studies, in vitro exposure to TCDD enhanced the spontaneous production of IgE by B cells isolated from atopic but not non-atopic individuals, but did not affect the levels of other isotypes.119 Other recent studies have reported small changes in immune cells from individuals exposed occupationally to PHAH.120121 For example, compared to unexposed controls, a cohort of men exposed occupationally to TCDD had diminished IFNy production in a recall response to tetanus toxin, while IFNy production following polyclonal activation was unaffected.120 This observation is consistent with mouse studies, in which antigen-specific responses are highly suppressed by TCDD, but mitogen-driven T cell responses are less susceptible to impairment.83 88122123... 

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