Mammalian lectin arrays for screening host–microbe interactions

Abstract

Many members of the C-type lectin family of glycan-binding receptors have been ascribed roles in the recognition of microorganisms and serve as key receptors in the innate immune response to pathogens. Other mammalian receptors have become targets through which pathogens enter target cells. These receptor roles have often been documented with binding studies involving individual pairs of receptors and microorganisms. To provide a systematic overview of interactions between microbes and the large complement of C-type lectins, here we developed a lectin array and suitable protocols for labeling of microbes that could be used to probe this array. The array contains C-type lectins from cow, chosen as a model organism of agricultural interest for which the relevant pathogen–receptor interactions have not been previously investigated in detail. Screening with yeast cells and various strains of both Gram-positive and -negative bacteria revealed distinct binding patterns, which in some cases could be explained by binding to lipopolysaccharides or capsular polysaccharides, but in other cases they suggested the presence of novel glycan targets on many of the microorganisms. These results are consistent with interactions previously ascribed to the receptors, but they also highlight binding to additional sugar targets that have not previously been recognized. Our findings indicate that mammalian lectin arrays represent unique discovery tools for identifying both novel ligands and new receptor functions.

Wall Teichoic Acid in Staphylococcus aureus Host Interaction

“…Although this response is generally considered to be protective against S. aureus in the skin it currently remains unresolved whether S. aureus detection by LCs benefits the host [19,26]. Interestingly, the interaction between langerin and WTA is not fully conserved across host species since β-1,4-GlcNAc-modified WTA is not recognized by mouse langerin or bovine langerin [19,27]. Consequently, the role of LCs may be underappreciated in commonly used murine experimental S. aureus infection models due to a lack of langerin-mediated detection.…”

Rapid Evolution of Glycan Recognition Receptors Reveals an Axis of Host-Microbe Conflicts at Carbohydrate-Protein Interfaces

“…Although this may make it challenging to identify the exact molecular changes or microbial species that have driven rapid evolution in these glycan PRRs, this system represents a unique opportunity to study the tradeoffs associated with rapid evolution, a topic that has been largely ignored in protein-protein arms races, where the focus has remained on 1:1 interactions between host proteins and highly specific pathogenic substrates. Recent advances in high-throughput profiling of host lectin interactions with complex microbial glycans when applied to these rapidly evolving PRRs will likely help to shed light on these questions of what drove these signals of evolution and what the consequences might be for specific microbial recognition (59,60).…”

C-Type Lectins in Veterinary Species: Recent Advancements and Applications

“…In conclusion, advancements in the understanding of CTL functions in veterinary species will open up new applications in veterinary medicine; yet, the current lack of knowledge clearly highlights the need for further research. To bridge this knowledge gap between model and target species, novel tools, such as recombinant bovine [ 61 ] and ovine [ 60 ] CTL receptor libraries, were recently generated. The role of the identified CTL interactions of veterinary relevant species with pathogens will be unravelled in further studies.…”

“…Plate-bound or soluble recombinant CTL-based fusion proteins can in turn be used for binding studies with bacteria, viruses, fungi, and parasites in order to identify interactions of CTLs with PAMPs [ 103 ]. In this regard, the lectin array technology offers excellent opportunities for the diagnosis of blood and urine infections [ 61 ] or protein glycosylation-associated disorders [ 104 ] in animal or human patients.…”

“…The murine [ 31 ] and ovine [ 60 ] CTL libraries were expressed as CTL-Fc fusion proteins. For the bovine [ 61 ] library, cow CTL and bacterial biotinylation site coding DNA fragments were fused and expressed in E. coli , yielding biotinylated fusion proteins that can be used for glycan array- and ELISA-based binding studies and high throughput pull-down assays.…”