| First Author | Amiot F | Year | 1997 |
| Journal | Eur J Immunol | Volume | 27 |
| Issue | 4 | Pages | 1035-42 |
| PubMed ID | 9130661 | Mgi Jnum | J:39519 |
| Mgi Id | MGI:86913 | Doi | 10.1002/eji.1830270434 |
| Citation | Amiot F, et al. (1997) Mice heterozygous for a deletion of the tumor necrosis factor-alpha and lymphotoxin-alpha genes: biological importance of a nonlinear response of tumor necrosis factor-alpha to gene dosage. Eur J Immunol 27(4):1035-42 |
| abstractText | The tumor necrosis factors (TNF-alpha and lymphotoxin, or LT-alpha) are important mediators of the immune and inflammatory responses, and it has been proposed that a positive feedback loop could boost the expression of the TNF to sufficiently high levels to fend off infections. To investigate this phenomenon and its biological consequences, we have generated LT-alpha/TNF-alpha knockout mice and compared mice having one or two functional LT-alpha/TNF-alpha alleles. In response to lipopolysaccharide (LPS) stimulation, TNF-alpha levels in the circulation or in the supernatant of macrophage cultures were 20- to 100-fold lower in heterozygous samples than in their wild-type counterparts. This differential increased with the intensity of stimulation and throughout the response, supporting the involvement of a positive feedback loop. Moreover, the heterozygous mice had an increased bacterial load following Listeria monocytogenes infection and exhibited a bimodal response to the association of D-galactosamine and LPS which was similar to that of wild-type mice at low doses of LPS and more like that of homozygous mutants at high doses. These results therefore establish the biological importance of the nonlinear response of TNF-alpha levels to gene dosage, and these mice provide a unique tool to study how the propensity to produce TNF can determine the immunological fitness of individuals. |
