Mice between 6–12 weeks old were used. C57Bl/6 mice were from The Jackson Laboratory (Bar Harbor, ME), Taconic Farms (Hudson, NY), or National Cancer Institute (Frederick, MD) or our own breeding colony. RAG1−/− mice and CCR2−/− mice were from Jackson Laboratory. CCR7−/− mice were as described (26 (link)). CCR2−/− mice were bred with CCR7−/− to generate CCR2−/−CCR7−/− mice. IL-1β−/− mice were as described (27 (link)). VEGF-lacZ mice were as described (11 (link), 12 (link), 28 (link)). All animal procedures were performed in accordance with the regulations of the Institutional Animal Use and Care Committee at the Hospital for Special Surgery (New York, NY).