BCG-Induced Dendritic Cell Responses and Suppression of Interleukin-5 Production from T Cells in Atopic Asthmatics

Bacille Calmette-Guerin (BCG) induces potent Th1 responses with the help of interleukin (IL)-10 and IL-12 released from dendritic cells (DCs), and suppresses Th2- associated allergic reactions. However, there are still some controversies on therapeutic effects of BCG in asthmatics. This study investigated whether BCG administration to DCs suppresses IL-5 production from T cells in atopic asthmatics. DCs derived from peripheral blood of subjects were cultured with or without BCG and Dermatophagoides farinae extract. Some DCs were co-cultured with T cells in the presence of BCG or the above culture supernatants. In the atopic asthmatics, BCG significantly increased IL-10 and IL-12 production from DCs. In the presence of D. farinae extract, BCG further increased IL-10 production. BCG-induced IL-10 production was significantly higher in the atopics (n=14) than in the non-atopics (n=9). Both BCG and the BCG-treated DCs culture supernatant significantly increased IFN-gamma production from T cells. Both BCG and the supernatant from DCs+BCG+D. farinae co-cultures significantly decreased IL-5 production (all p<0.05), but the supernatant from DCs+BCG co-cultures did not. In conclusion, administration of BCG together with D. farinae extract effectively decreased IL-5 production from T cells, probably through the action of IL-10 and IL-12 released from DCs in D. farinaesensitive asthmatics.

Murine Model of Buckwheat Allergy by Intragastric Sensitization with Fresh Buckwheat Flour Extract

Food allergies affect about 4% of the Korean population, and buckwheat allergy is one of the most severe food allergies in Korea. The purpose of the present study was to develop a murine model of IgE-mediated buckwheat hypersensitivity induced by intragastric sensitization. Young female C3H/HeJ mice were sensitized and challenged intragastricly with fresh buckwheat flour (1, 5, 25 mg/dose of proteins) mixed in cholera toxin, followed by intragastric challenge. Anaphylactic reactions, antigen-specific antibodies, splenocytes proliferation assays and cytokine productions were evaluated. Oral buckwheat challenges of sensitized mice provoked anaphylactic reactions such as severe scratch, perioral/periorbital swellings, or decreased activity. Reactions were associated with elevated levels of buckwheatspecific IgE antibodies. Splenocytes from buckwheat allergic mice exhibited significantly greater proliferative responses to buckwheat than non-allergic mice. Buckwheat-stimulated IL-4, IL-5, and INF-gamma productions were associated with elevated levels of buckwheat-specific IgE in sensitized mice. In this model, 1 mg and 5 mg dose of sensitization produced almost the same degree of Th2-directed immune response, however, a 25 mg dose showed blunted antibody responses. In conclusion, we developed IgE-mediated buckwheat allergy by intragastric sensitization and challenge, and this model could provide a good tool for future studies.

Citoquinas inducidas por la inmunización experimental antitetánica. Efecto de la formulación vacunal / [Cytokines induced by experimental anti-tetanus immunization. Vaccine formulation effect]

Several factors are involved in the selective activation of T helper 1 or T helper 2 cells, such as the type of antigen-presenting cells involved in the immune response and the different physical characteristics of antigens. The aim of this work was to evaluate if adding other antigens to tetanus toxoid modifies the original immune response. BALB/c mice were immunized with tetanus and diphtheria toxoids associated with whole-cell Bordetella pertussis (DTPw vaccine), B. pertussis soluble antigens (DTPa vaccine) or Salmonella typhi plus DTPa (DTPaSt vaccine). DTPw and DTPaSt immunization induced a T helper 1/T helper 2 (Th1/Th2) anti-tetanus response with gamma interferon and interleukin 5 production. DTPa immunization induced a Th2 response with production of interleukin 5 and interleukin 6. Only DTPw vaccine induced higher levels of IL-12 in non-immunized mice. Our findings indicate that the co-injection of whole-cell antigens such as B. pertussis or S. typhi, modifies the anti-tetanus response shifting it from Th2 to Th1 type. However, the original Th2 immune response is not modified when the vaccine consists only of soluble antigens.

The CD4+ Tcell network and the cytokine profile after HIV-1 infection

The present article discusses CD4+ T -cell interaction and cytokine production after HIV-1 infection and progression to AIDS. On the basis of the experience of the author with biological fluids obtained from patients suspected of having AIDS and the recently available data concerning this matter, a model is proposed for the CD4+ T -cells network and CD4+ T -cells destruction during this infection. The mechanism of cellular killing involves apoptosis and preferential destruction of activated TH0/TH2-type cells. This type of cells is generated as an immune response to HIV-1 itself or to allergens and helminth infestations. The virus replicates more effectively in activated TH0/TH2-type cells and this contributes to the development of full-blown AIDS. The author has previously proposed the hypothesis of an elevation in IL-5 production during later stages of the diseazse and the use of eosinophilia of unknown etiology as a prognostic marker of AIDS in developing countries (Caterino-de-Araujo (1994). Immunology Today, 15: 498-499). At the present time, this proposition is confirmed and the use of eosinophilia as an indicator of a shift to a TH0/TH2-type response that predicts progression to AIDS is justified