Figure 1. Tumor necrosis factor (TNF)–“floxed” mice were generated by homologous recombination in embryonic stem (ES) cells with subsequent removal of neo-cassette. Three different cell type–specific deleter mice were used to generate the experimental panel in the study. Beneficial (green) and detrimental (red) in vivo effects of TNF produced by various types of leukocytes are listed. LPS, lipopolysaccharide; SEB, staphylococcal enterotoxin B; MLys, macrophage lysozyme; loxP, target sequences for the site-specific Cre-recombinase.