MASP‐3: a new leptomeningeal protein in the lectin pathway

Abstract

IntroductionMASP‐3, a protein of the innate immune response is attracting increasing interest, in particularly in relation to its regulatory function in the lectin pathway.ObjectiveProvide data that discriminate the source of MASP‐3 in cerebrospinal fluid.Materials and methods60 serum and cerebrospinal fluid samples from normal controls without organic disease with normal barrier function were obtained. MASP‐3 was assayed in samples of cerebrospinal fluid and serum with an ELISA, coated with anti MASP‐3 antibodies. It takes into account three variables: the molecular size‐dependent concentration gradient between CSF and blood, the variation in transfer between blood and CSF, and the CSF MASP‐3 concentration correlation with the albumin CSF/serum quotient (Qalb), i.e., with CSF flow rate.ResultsMASP‐3 concentration in CSF was lower than its serum concentration but MASP‐3 concentration in CSF was at least three‐fold higher than expected for a molecular‐size dependent passage from blood. The smaller inter‐individual variation of MASP‐3 concentrations in CSF of the control group (CV =0,396) compared to the MBL concentrations in serum (CV=0.413) indicate an independent source of MASP‐3 in CSF. The absolute MASP‐3 concentration in CSF increases with increasing Qalb. Among brain‐derived proteins in CSF only the leptomeningeal proteins showed a (linear) increase with decreasing CSF flow rate in comparison to neuronal and glial proteins that are invariant to changes of Qalb.ConclusionsMASP‐3 in CSF is predominantly brain‐derived and all results pointed to the leptomeningeal cells as the source of the protein.This abstract is from the Experimental Biology 2018 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.