Premium
Xenopus laevis macrophage‐like cells produce XCL ‐1, an intelectin family serum lectin that recognizes bacteria
Author(s) -
Nagata Saburo
Publication year - 2018
Publication title -
immunology and cell biology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.999
H-Index - 104
eISSN - 1440-1711
pISSN - 0818-9641
DOI - 10.1111/imcb.12048
Subject(s) - chemistry , microbiology and biotechnology , phagocytosis , lipopolysaccharide , biology , immunology
Xenopus laevis Ca 2+ ‐dependent lectin‐1 ( XCL ‐1) is an intelectin family serum lectin that selectively recognizes carbohydrate chains on the bacterial cell surface. Immunofluorescence examination of control spleen tissues from normal X. laevis revealed cells producing XCL ‐1 ( XCL ‐1 + cells) exclusively in red pulps. Intraperitoneal injection of Escherichia coli lipopolysaccharide ( LPS ) caused a marked increase in the number of XCL ‐1 + cells in red pulps on day 3, followed by a rapid decrease to near control levels by day 7. XCL ‐1 + cells were also detected in peripheral blood leukocytes ( PBL s) and peritoneal exudate cells ( PEC s), and their numbers increased upon LPS injection until day 7. The XCL ‐1 + cells exhibited the morphological characteristics of macrophages, with a large oval or lobulated nucleus and abundant cytoplasm with vacuoles and dendritic projections. Western blot analyses revealed concurrent increases in XCL ‐1 levels in the spleen, PBL s, and PEC s. When LPS ‐stimulated frogs were intraperitoneally injected with paraformaldehyde‐fixed, green fluorescent protein‐labeled E. coli cells ( GFP ‐Eco), these were phagocytosed by XCL ‐1 + PEC s. The purified XCL ‐1 protein agglutinated GFP ‐Eco in a Ca 2+ ‐dependent manner, which was blocked effectively by xylose and partly by LPS and Staphylococcus aureus peptidoglycan, but not by sucrose. These results indicate that X. laevis macrophage‐like cells produce XCL ‐1 and suggest that XCL ‐1 promotes the clearance of invaded bacteria by facilitating phagocytosis.