Studies on in vitro IgE synthesis from lymph node cells of mice during infection with Nippostrongylus brasiliensis. Presence of inhibitory factor(s) in serum.

The effect of serum factors on Ig synthesis (IgE, IgG) in vitro was analyzed. Spleen and mesenteric lymph node cells were obtained from Nippostrongylus brasiliensis-infected and non-infected mice. Sera and ammonium sulphate precipitated serum fractions from mice of different genetic origin (Balb/c - H-2d, A.

Generation of cell-derived factors in vitro which modulate IgE synthesis.

Generation of IgE-specific suppressor factors in vitro upon stimulation of murine lymphocytes with IgE was studied. High-molecular weight factors (greater than 50 kilodalton) suppressed in vivo IgE response as well as de novo IgE synthesis in vitro. Further, suppression of IgE synthesis in vitro by fractions of low molecular weight supernatants absorbed with IgE-Sepharose was obtained, suggesting a potent role for IgE binding factors in IgE synthesis.

Generation of cell-derived factors suppressing IgE synthesis of Nippostrongylus brasiliensis-infected mice in vitro.

Modulation of de novo IgE synthesis in vitro was studied using the parasitic infection of mice with the nematode Nippostrongylus brasiliensis. Cell-derived factors were generated by stimulation of splenic and mesenteric lymph node cells of BALB/c mice with monoclonal IgE in vitro. High molecular weight (greater than 50,000) and low molecular weight (less than 50,000) culture supernatants were prepared.

Effect of thiol-activated toxins (streptolysin O, alveolysin, and theta toxin) on the generation of leukotrienes and leukotriene-inducing and -metabolizing enzymes from human polymorphonuclear granulocytes.

The generation of leukotrienes (LTC4, LTD4, LTE4, and LTB4; 12-epi-LTB4 isomer) from human granulocytes by thiol-activated toxins (streptolysin O, alveolysin from Bacillus alvei, and theta toxin from Clostridium perfringens) is described. The release occurs under noncytolytic conditions. Although LTB4 is the major component after calcium ionophore stimulation, more LTC4 as compared with LTB4 is released with the toxins.

The role of immunoglobulin E receptors in allergic diseases.

Recent studies presented evidence that subpopulations of lymphocytes, monocytes and eosinophils carry immunoglobulin (IgE)-specific membrane receptors which differ from the classical Fc epsilon-receptors on basophil granulocytes and mast cells. The analysis of IgE-receptor interactions with various cells has led to important insights as to the requirements of IgE-antibody regulations. In addition, the membrane biochemical mechanisms in the induction of mediator release became better understood.