No abstract

Previous reports indicate that the in vitro bactericidal activity of rat alveolar macrophages (AM) is dependent on the lipid fraction (ALM-L) of the alveolar lining material (ALM). The present study demonstrates that luminol-dependent chemiluminescence of stimulated rat AM is increased when rat AM are preincubated in the ALM or in the ALM-L. Evidence is presented that oxidation of the unsaturated lipids is responsible for the increase. In addition to pretreatment with the ALM, cells were also pretreated in commercial preparations of several lipids found to be present in the ALM. Preincubation in these lipids produced a significant increase in the luminol-dependent chemiluminescence response. However, when a saturated lipid, dipalmitoyl phosphatidylcholine, was used no increase was found. Pretreatment in ALM did not increase the nitro blue tetrazolium dye reduction by the AM, nor was the phagocytosis of latex beads by the AM altered by the addition of the ALM.

No abstract

Macrophage spreading, surface receptor density/avidity, phagocytosis, random migration, chemotactic responsiveness, and serum lysozyme were examined during the course of infection (up to 60 days) of mice with Brucella abortus strain 19. Markedly enhanced in vitro spreading activity was observed throughout the period of study. The density/avidity of cell surface immunoglobulin G Fc receptors was increased for up to 60 days postinfection. Internalization of sheep erythrocytes via C3 receptors was significantly enhanced. Random locomotion and chemotactic responsiveness to lymphocyte-derived chemotactic factor and N-formyl-L-methionyl-L-leucyl-L-phenylalanine were markedly stimulated. Serum lysozyme was also elevated in infected animals. These changes indicated significant and prolonged enhancement of macrophage activity during Brucella infection. These findings are discussed in relation to previous reports describing macrophage activation by Brucella.

No abstract