Purified monocytes were preincubated with or without anti-CD14 mAb MEM-18 and then primed LPS, TT, or SEB for 1 h. For further details, see Materials and Methods. These primed monocytes (1 × 10⁵/ml) were added to purified autologous T lymphocytes (1 × 10⁶/ml). DNA synthesis was measured after 4 days in SEB-stimulated cultures or after 7 days in LPS, TT, or unstimulated cultures, respectively. Data are expressed as mean ± SD of three parallel cultures.