The Effect of Neutropenia on Myeloid Growth and the Stem Cell in an In Vivo Culture System

Abstract

An in vivo diffusion chamber (DC) culture technique was used to evaluate the role of circulating humoral factors in the control of myelopoiesis. Normal mouse bone marrow cell suspensions sealed in DC’s were implanted intraperitoneally into mice or rats rendered neutropenic by pretreatment with cyclophosphamide, and the growth of cells in the DC’s was evaluated at intervals thereafter. When marrow was cultured in hosts with graded neutropenia, a dose-related augmentation of myelopoiesis was demonstrated. The growth of macrophages and of pluripotent stem cells, measured by the spleen colony-forming technique, was also enhanced by culture in neutropenic hosts. These data provide further evidence that the rate of myelopoiesis is influenced by a circulating humoral factor. They further suggest that a humoral or hormonal factor is important in control of the pluripotent stem cell population.

In vivo stimulation and inhibition of granulopoiesis: the effect of an inflammatory reaction on murine diffusion chamber granulopoiesis

“…In all experiments, 5 x 105 nucleated marrow cells in a volume of 0.1 ml were injected into each DC, and two DC were implanted into the peritoneal cavity of each host mouse one or several days after the initiation of acute inflammation or after a sham operation. In every experiment six to 10 DC from both stimulated and control hosts were removed at each time point, agitated for 1 h in HBSS containing 5% Ficoll and 0.5% pronase in order to lyse clots and the contents were harvested as described by Tyler et al (1972). Smears, differential counts and cell classification were performed as previously described (Symann et al, 1976).…”

Site of action of serum factors that block delayed-type hypersensitivity in mice.

“…Monocyte Precursors. The monocyte precursor in bone marrow is radiosensitive (27) and susceptible to cyclophosphamide (2,28,29). It is well known that monocytes are essential to the enactment of a DTH reaction in the skin (30) or foot-pad (27).…”

The Role of Colony Stimulating Activity in Modulating Murine Diffusion Chamber Granulopoiesis

“…Sera were collected, pooled, and frozen at -20°C until assays for CSA and inhibitors of in vitro granulopoiesis were carried out. Immediately after removal, D C were agitated for 1 h in sterile HBSS containing 5% Ficoll and 0.5% pronase in order to lyse clots, and the contents were harvested as previously described (Tyler et al, 1972). The marrow ofone tibia from each host mouse was flushed, and total nucleated cell counts were carried out on the pooled cells of each group.…”

“…A minimum of 500 cells per group were identified for differential DC cell counts, and a minimum of 5000 cells were identified for femoral marrow differential counts. The criteria described by Tyler et al (1972) were followed for the morphologic identification of murine D C and marrow nucleated cells.…”

“…Certain manipulations of the host animal cause stimulation or suppression of D C granulopoiesis through humoral mechanisms. Prior treatment of the host with irradiation (B0yum et al, 1972;Rothstein et al, 1971) or cyclophosphamide (Gordon & Blackett, 1975;Tyler et al, 1972) is predictably associated with augmentation of GMM proliferation within DC. Conversely, humoral substances from intact or disintegrated bone marrow cells (Rothstein et al, 1973), neutrophils (Bsyum et al, 1976 and neutrophilic extracts (Lovhaug & Brayum, 1977) have been convincingly demonstrated to suppress D C granulopoiesis.…”