RT Journal Article
SR Electronic
T1 Zebrafish Galectin 3 binding protein (Lgals3bp) is the target antigen of the microglial 4C4 monoclonal antibody
JF bioRxiv
FD Cold Spring Harbor Laboratory
SP 2022.04.05.486973
DO 10.1101/2022.04.05.486973
A1 Mireia Rovira
A1 Alice Montanari
A1 Latifa Hammou
A1 Laura Chomette
A1 Magali Miserocchi
A1 Jennifer Pozo
A1 Virginie Imbault
A1 Xavier Bisteau
A1 Valérie Wittamer
YR 2022
UL http://biorxiv.org/content/early/2022/04/07/2022.04.05.486973.abstract
AB Background Two decades ago, the fish-specific monoclonal antibody 4C4 was found to be highly reactive to zebrafish microglia, the macrophages of the central nervous system. This has resulted in 4C4 being widely used, in combination with available fluorescent transgenic reporters to identify and isolate microglia. However, the target protein of 4C4 remains unidentified, which represents a major caveat. In addition, whether the 4C4 expression pattern is strictly restricted to microglial cells in zebrafish has never been investigated.Results Having demonstrated that 4C4 is able to capture its native antigen from adult brain lysates, we used immunoprecipitation/mass-spectrometry, coupled to recombinant expression analyses, to identify its target. The cognate antigen was found to be a paralog of Galectin 3 binding protein (Lgals3bpb), known as MAC2-binding protein in mammals. Notably, 4C4 did not recognize other paralogs, demonstrating specificity. Moreover, our data show that Lgals3bpb expression, while ubiquitous in microglia, also identifies leukocytes in the periphery, including populations of gut and liver macrophages.Conclusions The 4C4 monoclonal antibody recognizes Lgals3bpb, a predicted highly glycosylated protein whose function in the microglial lineage is currently unknown. Identification of Lgals3bpb as a new pan-microglia marker will be fundamental in forthcoming studies using the zebrafish model.Competing Interest StatementThe authors have declared no competing interest.