Examination of the cells recovered from the pouch fluid obtained from MGL1-deficient mice. An antigenic challenge was performed and cells in the pouch were collected on day 3. The CD45-negative cells were separated from the pouch fluid cell suspensions by MACS and were labeled with PHK-26. The labeled cells mixed with IL-1α (50 μg/mL) were injected into the pouch on MGL1-deficient mice on day 3. The injected cells, which were labeled with PKH26 (B), were shown also to be ER-TR7–positive and classified into fibroblasts (A). Bars represent 5 μm.