Increased activity of FIM in serum of mice during a Mycobacterium bovis (BCG) infection.

In mice given an intravenous injection of Mycobacterium bovis (BCG), the bacilli proliferated in the spleen, liver and lungs but the peritoneal cavity remained sterile. The numbers of blood monocytes and alveolar macrophages were increased during the first 2 weeks of the infection, whereas the number of peritoneal macrophages remained constant. To study whether factor-increasing monocytopoiesis (FIM) plays a role in the regulation of the monocytosis during the BCG infection, the activity of this factor in the serum of mice at various intervals during the infection was determined.

Effect of lung surfactant on the release of factor increasing monocytopoiesis by macrophages.

Upon ingestion of particulate and soluble material, at the site of an inflammation macrophages release the factor increasing monocytopoiesis (FIM), which accelerates the rate of division of the monoblasts and promonocytes in the bone marrow. It is not known, however, whether FIM is released by macrophages present at noninflamed sites. Since FIM is secreted only during phagocytosis and alveolar macrophages ingest surfactant in vivo, the present study was performed to find out whether surfactant induces the release of FIM by alveolar macrophages.

Regulation of granulocyte responses in the blood and peritoneal cavity of CBA and B10 mice during an acute inflammation.

The regulatory mechanisms that determine the course of an inflammation induced by an intraperitoneal injection of kaolin were investigated in Listeria-susceptible CBA and Listeria-resistant B10 mice. The magnitude of the granulocyte inflammatory response in the peritoneal cavity was high in B10 mice (area under the curve; AUC0-48 h: 210.9 x 10(6) granulocytes/mouse x h) and lower in CBA mice AUC0-48 h: 136.

Macrophages as origin of factor increasing monocytopoiesis.

Earlier investigations had indicated that the factor increasing monocytopoiesis (FIM), present in the serum of mice and rabbits during the onset of an inflammatory response, is released by cells of the inflammatory exudate. The present study was performed to determine which cells produce and secrete this factor and to establish the kinetics of its production and secretion. FIM was assayed in vivo by intravenous injection of samples into untreated mice and monitoring the course of the number of blood monocytes in the recipients.

Cell kinetic analysis of a murine macrophage cell line.

For the present study, which was performed to find a reliable method suitable for determination of the cell kinetic parameters of a continuous cell line, use was made of the macrophage cell line J774.1. The doubling time of the cell population was approximately 27 h.

Morphological, cytochemical, functional, and proliferative characteristics of four murine macrophage-like cell lines.

The aim of the present study was to obtain objective data on the morphology and quantitative information about other characteristics of murine macrophage-like cell lines J774.1, PU5-1.8, WEHI-3, and P388-D1, and to compare the findings with those in resident and exudate macrophages collected directly from mice.

Method to select mice in the steady state for biological studies.

Collection of small amounts of blood from the orbital sinus was found to be a satisfactory method for repeated sampling in mice, which means that these animals can be selected for further study on the basis of the leukocyte count. In biomedical research it is often necessary to have detailed information about the effect of injected material on the numerical course of circulating leukocytes. However, the present study has shown that 2 stress-producing procedures on 1 day disturb the steady state, and that this disturbance is expressed in changes in the number of leukocytes.

Differences in the response of inbred mouse strains to the factor increasing monocytopoiesis.

Previous studies have shown that monocyte production during an inflammatory response is controlled by the factor increasing monocytopoiesis (FIM), secreted by macrophages at the site of inflammation. The inflammatory reaction to latex particles and a saline-soluble extract of Listeria monocytogenes (SEL), expressed as the number of monocytes in the circulation and of macrophages at the site of inflammation, was about twice as strong in C57BL/10 mice compared with CBA mice. This raised the question as to the mechanism underlying these differences.

Presence of the factor increasing monocytopoiesis (FIM) in rabbit peripheral blood during an acute inflammation.

An intraperitoneal injection of latex in rabbits was found to give rise to an increase in the number of macrophages at the site of inflammation and a concomitant monocytosis in the peripheral blood. The results showed that during the initial phase of the inflammatory reaction a humoral factor is present in the circulation of these animals that stimulates the monocyte production in the bone marrow in a concentration-dependent way. This factor has been called the factor increasing monocytopoiesis (FIM), in analogy with the name given to the factor previously found in mice.

Culture of mononuclear phagocytes on a teflon surface to prevent adherence.

A method is described for the culture of mononuclear phagocytes in suspension by incubation on a Teflon film to which the cells do not adhere. The characteristics of peritoneal macrophages, bone marrow mononuclear phagocytes, macrophage cell lines, and fibroblasts cultured in this way are similar to those observed after culture on glass or plastic surfaces. Culture of mononuclear phagocytes in Teflon film dishes has three important advantages: the cells can be easily harvested without damage, recovery is almost complete, and the cells are not functionally impaired.