Ficolins and the Recognition of Pathogenic Microorganisms: An Overview of the Innate Immune Response and Contribution of Single Nucleotide Polymorphisms.

Stefan Bidula,Silke Schelenz,Darren W Sexton

doi:10.1155/2019/3205072

Abstract

Ficolins are innate pattern recognition receptors (PRR) and play integral roles within the innate immune response to numerous pathogens throughout the circulation, as well as within organs. Pathogens are primarily removed by direct opsonisation following the recognition of cell surface carbohydrates and other immunostimulatory molecules or via the activation of the lectin complement pathway, which results in the deposition of C3b and the recruitment of phagocytes. In recent years, there have been a number of studies implicating ficolins in the recognition and removal of numerous bacterial, viral, fungal, and parasitic pathogens. Moreover, there has been expanding evidence highlighting that mutations within these key immune proteins, or the possession of particular haplotypes, enhance susceptibility to colonization by pathogens and dysfunctional immune responses. This review will therefore encompass previous knowledge on the role of ficolins in the recognition of bacterial and viral pathogens, while acknowledging the recent advances in the immune response to fungal and parasitic infections. Additionally, we will explore the various genetic susceptibility factors that predispose individuals to infection.

Highlights

Ficolins are innate pattern recognition receptors (PRRs) similar to the collectin, the mannose-binding lectin (MBL), and the surfactant proteins (SP)
We describe updates on the opsonic activity of human and rodent ficolins and explore their role within innate immune responses against pathogens
Liu et al [33] found that L-ficolin in patients with hepatitis C virus (HCV) was elevated and was able to bind to N-glycans of the envelope glycoproteins E1 and E2

Summary

Introduction

Ficolins are innate pattern recognition receptors (PRRs) similar to the collectin, the mannose-binding lectin (MBL), and the surfactant proteins (SP). In the ficolins, the carbohydrate-recognition domain (CRD) of the collectins is replaced by a C-terminal fibrinogen-like domain (FBG; Figure 1(a)). In their native form, ficolin monomers assemble to form trimers via their collagen-like domains, before further assembling into oligomeric bouquet-like structures of between 4 and 6 trimers. Ficolins function within innate immunity via the recognition of pathogen-associated molecular patterns (PAMPs) on microbial pathogens. All of the human and rodent ficolins have been observed to activate the lectin-complement pathway (Figures 1(b) and 1(c)) following the association with. We describe updates on the opsonic activity of human and rodent ficolins and explore their role within innate immune responses against pathogens. We briefly discuss the effects of single nucleotide polymorphisms on pathogen susceptibility

The Ligand-Binding Properties of Ficolin

The Role of M-Ficolin in Immunity to Pathogenic Microorganisms

The Role of L-Ficolin in Immunity to Pathogenic Microorganisms

The Role of H-Ficolin in Immunity to Pathogenic Microorganisms

Findings

Conclusions