Suppression of bacteria-induced cytokine production by freshly isolated monocytes by blocking antibodies against CD163. (A) Human monocytes were incubated with S mutans bacteria (100 bacteria/cell) in the presence of blocking (EDhu2 or EDhu3) or nonblocking (EDhu4) antibodies against CD163, and cytokine production was measured in supernatants after 4 hours (TNF-α) or 18 hours (IL-1β and IL-6). Means plus or minus SD from triplicate incubations of a representative experiment of 4 are shown. Statistics: 2-tailed Student t test. (B) Flow cytometric analysis of CD163 expression on monocytes using EDhu1, EDhu2, EDhu3 and EDhu4 mAb. Histograms show control cells stained without primary antibody (dotted line) or with the indicated anti-CD163 mAb. Note that monocytes express only moderate levels of surface CD163.