Search

The aim of this study was to investigate the role of immunoglobulin E (IgE) in the late phase reaction (LPR) of murine experimental asthma. Our model consisted of an implant of DNP-conjugated, heat-coagulated hen's egg white (DNP-EWI), followed 14 days later by an intratracheal challenge with aggregated DNP-ovalbumin. Airway inflammation was analyzed 48 h after challenge and compared with a similarly immunized group of mice with highly suppressed humoral response due to anti- μ and anti- δ antibody treatment. Total number of cells in the bronchoalveolar lavage (BAL) (with predominance of eosinophils) and EPO activity in the lung homogenate were increased in the DNP-EWI-immunized group compared with immunosuppressed or nonimmunized mice. However, the cellular infiltration and EPO activity observed in the immunosuppressed group were still significantly above those obtained in the nonimmunized group, indicating that inhibition of antibody production did not completely prevent the inflammatory manifestations in BAL and lung. Airway hyperresponsiveness to methacoline was obtained in DNP-EWI-immunized mice, but the respiratory mechanical parameters returned to normal levels in the immunosuppressed group. When these mice were reconstituted with monoclonal anti-DNP antibodies, only IgE, but not IgG1, restored lung inflammation and decreased the conductance of the respiratory system, therefore, increasing hyperresponsiveness. These results indicate that antibodies are not essential for induction of LPR in the lung. However, IgE enhances pulmonary inflammation and hyperresponsiveness. [ABSTRACT FROM AUTHOR]

Reports on the effect of X irradiation on homocytotropic and agglutinating antibody production in mice exposed to 400 rad either before or after immunization with dinitrophenylated Ascaris plus aluminum hydroxide as adjuvant. Enhancement of immunoglobulin (Ig) E and slight enhancement of IgM-antibody formation following irradiation one day before immunization.

The adjuvant activity of saponin for T-cell responses was evaluated and compared with that of complete Freund's adjuvant (CFA) in two antigen systems: a lysate of the protozoa Trypanosoma cruzi and ovalbumin (OA). Strong delayed-type hypersensitivity and T-cell proliferate responses, comparable with those stimulated by CFA, were observed for both antigens following immunization with saponin as adjuvant. Upon in vitro secondary antigen stimulation, high interleukin-10 (IL-10) and low interferon-γ (IFN-γ) levels were observed in lymph node (LN) cell cultures from saponin-immunized mice in contrast with the high IFN-γ and decreased IL-10 production by LN cells from CFA-immunized mice. Production of IL-10 and IFN-γ in these conditions was CD4-activation dependent. Concanavalin A (Con A)-stimulated interleukin-4 (IL-4) production was higher in saponin-immunized mice than in CFA-immunized mice. IL-10 produced by LN cells from saponin-immunized mice suppressed IFN-γ production and Con A-induced proliferation. Taken together, these data are consistent with in vivo stimulation of both T-helper (Th)1 and Th2-type cells by immunization with saponin; in vitro a Th2-type cytokine response with high IL-10 production predominates, indicating preferential priming towards a Th2-type response. Immunization with CFA induced a Th1-type cytokine response. To our knowledge, this is the first report in which an adjuvant is shown to prime for a dominant IL-10 production. [ABSTRACT FROM AUTHOR]