THE EFFECT OF FACTORS INFLUENCING CELLULAR cAMP ON PHAGOCYTOSIS AND LYSOSOMAL ENZYME RELEASE BY MOUSE MACROPHAGES

Isolation of variants in phagocytosis of a macrophage-like continuous cell line.

“…However, the concentration of cholera toxin required for this effect was 1,000 times greater than that needed optimally to elevate cAMP in their hands, and it may be questioned whether the effect was primarily related to the action of cholera toxin in raising cAMP levels or to some secondary effect. Secondly, Cruchard et al (20) have reported an inhibitory action of dibutyryl cAMP on Fc-mediated phagecytosis at a minimum concentration of 10 -~ M. Since the enhancement we have observed occurs at a concentration of 5 × 10 -4 M, it is difficult directly to compare these observations. Since we have isolated some variants that were enhanced in phagocytosis by 8 Br-cAMP and some that were not, it might not be unreasonable to consider two components of Fc-mediated phagocytosis, one dependent on cAMP, the other independent.…”

Dynamics of the Macrophage Plasma Membrance

“…Antigen uptake by macrophages occurs in vivo and in vitro and is not reduced by prior irradiation of the cells (164,(260)(261)(262). Both autologous and heterolo gous albumin and immunoglobulin are ingested by nonsensitized murine macrophages at comparable rates (44,224). A more critical factodnvolves the form of antigen presentation; aggregated horse and mouse albumin are more rapidly ingested than the nonaggregated fo rms (224).…”

“…The kinetics and qualitative aspects of antigen uptake (164,224,(260)(261)(262), the localization of antigen (30,44,263), and its immunogenicity at the membrane surface have been demonstrated (45,259,264,274). Antigen uptake by macrophages occurs in vivo and in vitro and is not reduced by prior irradiation of the cells (164,(260)(261)(262).…”

Combinative ligand‐receptor interactions: Epinephrine depresses RAW264 macrophage antibody‐dependent phagocytosis in the absence and presence of met‐enkephalin

“…Various neuroendocrine mediators are capable of enhancing or depressing phagocyte effector functions (Cruchaud et al, 1976;Foris et al, 1986;Goldman et al, 1983;Hartung and Toyka, 1983;Ignarro and George, 1974;Koff and Dunegan, 1985;Malone et al, 1986;Sung et al, 1985;Sharp et al, 1985;Tecoma et al, 1986). In general, opioids have been found to enhance effector functions, whereas adrenergic agonists depress effector functions.…”