Pre-incubation of RAW264.7 cells for one hour with the NMDA receptor antagonist, MK-801 (150 μΜ), also inhibited TNF secretion by these cells after stimulation with antibiotic-exposed CA-MRSA strains (MW2 or LAC, Figure 3 ). In response to stimulation with MW2 in the presence of vancomycin, pre-incubation with MK-801 significantly inhibited TNF secretion by these cells, i.e., from 32,407 ± 1,188 pg/mL to 23,337 ± 1,272 pg/mL (approximately 28% reduction; p < 0.05, Figure 3 , upper panel). MK-801 also inhibited macrophage TNF secretion in response to vancomycin-exposed LAC, causing a 34% reduction (Figure 3, upper panel) . Pre-incubation with MK-801 also significantly inhibited macrophage TNF secretion in response to daptomycin-treated MW2 or LAC (Figure 3 , lower panel). In response to stimulation with MW2 in the presence of daptomycin, pre-incubation with MK-801 inhibited TNF secretion by these cells by approximately 26% (from 22,305 ± 648 pg/mL to 16,437 ± 642 pg/mL, p < 0.05). MK-801 inhibited macrophage TNF secretion in response to daptomycin-exposed LAC by approximately 33% (from 22,164 ± 864 pg/mL to 14,647 ± 832 pg/mL, p < 0.05).