PubMed Health⌕ Search

Biomedical subjects

J A Krick

Publications and source records attributed to J A Krick.

11 recordsLinked to original sources
PubMed1980

Effects of human neutrophils and monocytes on Nocardia asteroides: failure of killing despite occurrence of the oxidative metabolic burst.

To study mechanisms of resistance to Nocardia asteroides in vitro, suspensions of human neutrophils and monocytes were challenged with N. asteroides in the presence of autologous serum. At 4 hr, numbers of viable N. asteroides incubated with neutrophils and monocytes averaged only 10% and 21% less, respectively, than numbers of N. asteroides incubated without phagocytes. In contrast, a mean of > 90% of Listeria monocytogenes and Staphylococcus aureus incubated with neutrophils and monocytes was killed. The failure to kill N. asteroides was not associated with absence of an oxidative metabolic burst by the phagocytes, since chemiluminescence occurred when phagocytes encountered N. asteroides and was blocked in preparations of N. asteroides and neutrophils by preincubation of the neutrophils with chlorpromazine. Thus, when cultured in suspension, human neutrophils and monocytes are unable to kill significant numbers of N. asteroides despite the occurrence of an oxidative metabolic burst.

Animals↗
PubMed1975

Resistance to infection with Nocardia asteroides.

Mechanisms of host resistance to Nocardia asteroides were studied in mice. Two to six weeks after intraperitoneal or intravenous immunization with viable N. asteroides, mice were significantly resistant to intraperitoneal challenge with LD50-100 of N. asteroides in gastric mucin when compared with control (unimmunized) mice (P smaller than 0.03). Resistance could not be transferred to normal mice with serum (1.5 ml administered intraperitoneally) or spleen cells (10-8 cells administered intravenously) from immune donor mice. Peritoneal macrophages from mice immunized with N. asteroides were activated by an in vitro L-cell inhibition assay, and these mice were resistant to challenge with Listeria monocytogenes. Mice with infections caused by Toxoplasma gondii or L. monocytogenes--infections producing activated macrophages--were resistant to challenge with N. asteroides.

Animals↗