CEACAM1 and listeriosis: In agreement with this role for CEACAM1, we have previously shown that CEACAM1 regulates granulopoiesis and the systemic response to Listeria monocytogenes infection via the G-CSFR-STAT3 pathway [12], and the IL-1β response to LPS in neutrophils by a TLR4-Syk pathway [13].