Anti-PE IgM antibodies are a universal trait of mammals and may represent an innate immune mechanism

GIMENEZ, G.; JACOBSEN FLORIN-CHRISTENSEN, M.; PAPPALARDO, S; ZAMORANO, P.; ISOLA, E.; SUAREZ, C.; FLORIN-CHRISTENSEN, J.

BIOCELL

Sociedad Latinoamericana de Microscopía Electrónica.; Centro Regional de Investigaciones Científicas y Tecnológicas

Año: 2005 vol. 29 p. 147 - 147

0327-9545

Knowledge on phospholipids of plasma lipoproteins has long been acquired. For unknown reasons, the phosphatidylethanolamine (PE) content of these complexes is strikingly lower than that in cell membranes. On the other hand, it is also well known that PE is the main phospholipid in most enteric bacteria. We here report the universal presence of anti-PE IgM antibodies throughout mammals, as detected by an ELISA assay and confirmed by immunoblotting. By contrast, anti-phosphatidylcholine (PC) IgMs are less than half of those observed against PE, with the notable exception of mice. Presence of antibodies against sphingomyelin (SM), a major lipoprotein component, is almost negligible. Natural anti-phospholipid antibodies were confined to the IgM isotype in all cases. No anti-phospholipids IgGs were detected. The diversity of species in which anti-PE IgMs were observed, is an indication that their presence is a universal phenomenon that affects all mammals. We propose that these novel anti-PE IgMs, represent a common innate defense system against infection by gut resident bacteria, and that the low lipoprotein PE is an adaptation that allows the operation of these antibodies by preventing their binding to plasma components, and consequently their free availability. Supported by ANPCyT and CONICET.