This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Reprints and Permissions Copyright Information Books from ASM Press MicrobeWorld Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by McCabe, R E Articles by Remington, J S Search for Related Content PubMed PubMed Citation Articles by McCabe, R E Articles by Remington, J S

Mechanisms of killing of Toxoplasma gondii by rat peritoneal macrophages.

ABSTRACT

Rats are resistant to Toxoplasma infection, and macrophages are thought to mediate this resistance. We performed a series of experiments to investigate the mechanism of the anti-Toxoplasma activity of resident rat peritoneal macrophages. Resident rat peritoneal macrophages killed more than 90% of ingested Toxoplasma gondii in vitro. This capacity was reduced progressively with the prolongation of culturing of macrophages in vitro before challenge with T. gondii. Exhaustion of the respiratory burst of macrophages with phorbol myristate acetate impaired their ability to kill and limit the replication of T. gondii. Histidine and diazabicyclooctane, presumed scavengers of singlet oxygen, were the only members of a battery of scavengers of metabolites of the respiratory burst that impaired the anti-Toxoplasma activity of macrophages. Ingestion of heat-killed Candida albicans by macrophages reduced large amounts of intracellular Nitro Blue Tetrazolium dye, whereas little dye was reduced by the ingestion of T. gondii. Challenge of macrophages with T. gondii released no detectable superoxide anion, as measured by the reduction of ferricytochrome c, whereas stimulation of macrophages with phorbol myristate acetate or ingestion of heat-killed Candida by macrophages released abundant superoxide anion. These data are consistent with the contributions of oxygen-dependent and oxygen-independent mechanisms to the anti-Toxoplasma activity of rat peritoneal macrophages. In addition, neonatal rats are known to be susceptible to Toxoplasma infection in vivo. However, resident neonatal rat peritoneal macrophages ingested and killed T. gondii to the same extent as did adult macrophages. Thus, the susceptibility of neonatal rats to Toxoplasma infection probably resides in other aspects of macrophage function or the immune response.

This article has been cited by other articles:

• Fux, B., Nawas, J., Khan, A., Gill, D. B., Su, C., Sibley, L. D. (2007). Toxoplasma gondii Strains Defective in Oral Transmission Are Also Defective in Developmental Stage Differentiation. Infect. Immun. 75: 2580-2590 [Abstract] [Full Text]  
• Cavailles, P., Sergent, V., Bisanz, C., Papapietro, O., Colacios, C., Mas, M., Subra, J.-F., Lagrange, D., Calise, M., Appolinaire, S., Faraut, T., Druet, P., Saoudi, A., Bessieres, M.-H., Pipy, B., Cesbron-Delauw, M.-F., Fournie, G. J. (2006). The rat Toxo1 locus directs toxoplasmosis outcome and controls parasite proliferation and spreading by macrophage-dependent mechanisms. Proc. Natl. Acad. Sci. USA 103: 744-749 [Abstract] [Full Text]