Increase in the number and the phagocytic function of guinea pig pulmonary and peritoneal macrophages following oral administration of RU 41740, a glycoprotein extract from Klebsiella pneumoniae.

RU 41740 (Biostim) which is a purified glycoprotein extract from Klebsiella pneumoniae, is an orally active non-specific immunostimulant. In guinea pigs, 8 days after a 7 days oral administration of RU 41740 (10 or 100 mg/kg/day), an increase in the cell population of the pulmonary and peritoneal cavities was observed, especially in that of the macrophages. RU 41740 also enhanced the phagocytic activity of both the alveolar and peritoneal macrophages, when their chemotactic activity was not significantly modified.

Increased complement-mediated leukocytic histamine release in atopics.

Complement-mediated leukocytic histamine release was compared in normal and atopic subjects using isolated leukocytes or heparinized blood. Leukocytes were treated with zymosan-activated autologous serum, whereas blood was directly incubated with zymosan particles. Histamine released from basophils into the leukocyte supernatant or plasma was measured spectrofluorometrically and expressed in percent of total histamine.

Depression of neutrophil chemotaxis in atopic individuals. An H2 histamine receptor response.

Neutrophil chemotaxis was compared in normal and atopic individuals using a modified Boyden chamber with as chemotactant, autologous serum either unactivated or activated by zymosan or an endotoxin-containing house dust preparation. A high incidence of defective leukotaxis was found in atopics when cells were opposed to activated serum. The cause of this abnormality is not intrinsic to the leukocytes since random migration and chemotaxis towards unactivated serum were comparable in normal and atopic subjects.