DNA Synthesis in Inflammatory Cells of Immunized and Non-Immunized Mice. ∗

Summary

Inflammatory cells aspirated from the peritoneal cavity of mice injected with Diphtheria toxoid were studied by autoradiography for in vitro incorporation of tritiated thymidine. The proportion of labeled cells was low prior to and for the first 2 days following initiation of inflammation. Beginning on the 3rd day the proportion of labeled cells gradually increased reaching a maximum on or about the 7th day in the non-sensitized mice. In animals previously sensitized to the Diphtheria toxoid, the increase in labeled cells occurred more rapidly, reaching a maximum on or about 5th day of inflammation. However, number of cells capable of DNA synthesis in both groups appeared to be identical. The origin of inflammatory mononuclear cells was discussed. Only a small proportion of the cells originate by division of cells suspended in the inflammatory exudate. The majority of cells, both granulocytes and mononuclear cells, migrate into the inflammatory area from the blood vessels and possibly from adjoining tissues.