Phagocytic Activity Of Alveolar Macrophages Research Articles

Effect of ammonia on in vivo and in vitro immune responses

The effects of exposure of animals to ammonia on their delayed type of dermal response, the mitogenic and antigenic responses of their lymphocytes, and the bactericidal and phagocytic activities of their alveolar macrophages were examined. Experimental guinea pigs vaccinated with Mycobacterium bovis BCG were exposed to 3.75 micrograms of ammonia per dl of air (50 ppm) or 6.75 micrograms of ammonia per dl of air (90 ppm), whereas control animals also vaccinated with BCG were maintained in the normal environment. The delayed type of dermal response to tuberculin injected 3 weeks later was significantly (P less than 0.05) less in experimental animals exposed to 6.75 micrograms of ammonia per dl than in control animals. In vitro, the response of blood lymphocytes and bronchial lymphocytes to phytohemagglutinin, concanavalin A, and tuberculin stimulation was significantly (P less than 0.01) less than the response of lymphocytes from control animals. The response of normal blood lymphocytes to phytohemagglutinin incubated in medium containing 1 or 10 mg of ammonia per dl was significantly (P less than 0.01) reduced as compared with the response of lymphocytes incubated without ammonia. The viability of lymphocytes incubated with these concentrations of ammonia was significantly (P less than 0.01) affected. There was no significant difference in the bactericidal or phagocytic activities of alveolar macrophages collected from animals exposed to ammonia and control animals. However, ammonia added to the culture of alveolar macrophages from normal animals significantly inhibited their bactericidal activity.

Chemiluminescence measurement of phagocytic activity of pulmonary macrophages in sarcoid alveolitis.

The phagocytic activity of alveolar macrophages in a group of patients with stage I and stage II fresh sarcoidosis has been studied in comparison with a group of healthy volunteers. The phagocytic activity has been measured by means of chemiluminescent emission recording. While no difference in the emission of chemiluminescence has been detected in polymorphonuclear leukocytes of patients and control subjects, a greater emission of chemiluminescence has been noted in the alveolar macrophages of sarcoid patients. Such a difference is statistically significant; its possible relation to alveolar inflammation has been considered.

Macrophage Dysfunction After Burn Injury

The phagocytic and microbicidal activities of alveolar and peritoneal macrophages were evaluated 4 and 24 h after a full-thickness scald burn of 26 to 28% body surface area in anesthetized rats. The contribution of serum factors to the macrophage functions was studied concurrently. The phagocytic activity of alveolar macrophages obtained 4 or 24 postburn was reduced approximately 65% below control values when they were incubated in media containing autologous serum and approximately 45% (below controls) when they were incubated in media containing normal (control) serum. A similar, although not as marked, decrease in the phagocytic activity of peritoneal macrophages was also demonstrated. Serum obtained from rats 4 or 24 h postburn had a significant suppressive effect on the phagocytic activity of control alveolar, but not peritoneal, macrophages. The intracellular microbicidal activity of peritoneal macrophages obtained at the postburn intervals and incubated in media containing either autologous or control serum was unaltered from control values. However, alveolar macrophages obtained 24 h, but not 4 h, postburn had a significant (approximately 80%) increase, above control values, in their microbicidal activity. Serum obtained 24 h, but not 4 h, postburn stimulated control alveolar macrophage killing ability. These data indicate that thermal injury induces a defect in the phagocytic activity rather than the microbicidal activity of macrophages. This phagocytic alteration is mediated, in part, by serum.

Phagocytosis by sheep alveolar macrophages: relationship between opsonin concentration and light emission in the presence of luminol.

The observations reported may be applied to determining the effects of various compounds, e.g., environmental pollutants and agricultural chemicals, upon the phagocytic activity of alveolar macrophages, and the method described will aid in detecting compounds which alter Fc receptor activity. A direct linear relationship existed between the concentration of antibody used to opsonize bacterial particles and the quantity of luminol-dependent light emitted by a population of sheep alveolar macrophages exposed to the opsonized particles. The relationship can be illustrated with a Lineweaver-Burk-style double-reciprocal plot. An analogy is suggested between the kinetics of enzyme substrate reactions and the interaction of antibody-coated particles with Fc receptors on cell membranes.

Effect of Trace Metals on Phagocytosis by Alveolar Macrophages

Experiments were performed to measure the effect of trace metals on a vital function of the alveolar macrophage (AM), phagocytosis. Since certain trace metals were found to reduce the viability of AMs, a technique was developed to permit examination of live cells only for phagocytosis. Evidence is presented that Ni(2+) selectively altered the phagocytic activity of AMs at concentrations lower than those which caused cell death. It is further shown that a level of VO(3) (-) that caused extensive lysis and death did not reduce phagocytosis in surviving cells. The effects of Cd(2+), Cr(3+), and Mn(2+) on AMs were also examined.