CSF have been postulated to be important mediators of host defenses. The current studies were undertaken to investigate the production of CSF by Listeria-specific, T cell clones and to assess the participation of CSF in anti-listerial host resistance. Listeria-specific L3T4+, Lyt-2- T cell clones were isolated and expanded by standard techniques. The clones themselves protected mice from listerial challenge when injected intravenously, and supernatants generated from Ag-stimulated clones were protective. In order to define factors important in the protection, supernatants from the clones were assayed for CSF by several in vitro assays. Total colony-stimulating activity was measured with a bone marrow colony-forming assay. T cell clones secreted 1000 to 2000 U/ml of colony-stimulating activity after 48 hours of stimulation with specific antigen. The relative amounts of the various CSF were determined by the capacity of supernatants to support proliferation of the factor-dependent cell lines FDCP-1 and 32D cl 3 in the presence and absence of specific anti-CSF antibodies. Results showed that most of the CSF activity was due to granulocyte-macrophage (GM)-CSF and IL-3. The role of GM-CSF in anti-listerial host resistance was assessed in two types of experiments. In one set of experiments GM-CSF activity was neutralized in the supernatants by addition of specific rabbit anti-GM-CSF antibodies. Treated and untreated supernatants were then tested for their capacity to protect nonimmune mice against listerial challenge. Neutralization of GM-CSF in the supernatants decreased the protective capacity of the supernatants by approximately 23%. In a second set of studies, the administration of recombinant murine GM-CSF was shown to protect mice from challenges of L. monocytogens. Taken together, these experiments provide evidence that CSF are important mediators of immune T cell mediated host defenses.
|Original language||English (US)|
|Number of pages||6|
|Journal||Journal of Immunology|
|State||Published - 1989|
ASJC Scopus subject areas
- Immunology and Allergy