Targeting of the C-Type Lectin Receptor Langerin Using Bifunctional Mannosylated Antigens

Abstract

Langerhans cells (LCs) are antigen-presenting cells that reside in the skin. They uniquely express high levels of the C-type lectin receptor Langerin (CD207), which is an attractive target for antigen delivery in immunotherapeutic vaccination strategies against cancer. We here assess a library of 20 synthetic, well-defined mannoside clusters, built up from one, two, and three of six monomannosides, dimannosides, or trimannosides, appended to an oligopeptide backbone, for binding with Langerin using surface plasmon resonance and flow cytometric quantification. It is found that Langerin binding affinity increases with increasing number of mannosides. Hexavalent presentation of the mannosides resulted in binding affinities ranging from 3 to 12 µM. Trivalent presentation of the dimannosides and trimannosides led to Langerin affinity in the same range. The model melanoma gp100 antigenic peptide was subsequently equipped with a hexavalent cluster of the dimannosides and trimannosides as targeting moieties. Surprisingly, although the bifunctional conjugates were taken up in LCs in a Langerin-dependent manner, limited antigen presentation to cytotoxic T cells was observed. These results indicate that targeting glycan moieties on immunotherapeutic vaccines should not only be validated for target binding, but also on the continued effects on biology, such as antigen presentation to both CD8 + and CD4 + T cells.

Lipid-Based Nanoparticles for Delivery of Vaccine Adjuvants and Antigens: Toward Multicomponent Vaccines

“…182 DC-SIGN and Langerin receptor (CD207) are two other mannose-binding CLRs. 183,184 Langerin receptor is mostly expressed on Langerhans cells (LC), which populate the skin epidermis and all stratified epithelia. It is also found on dermal DCs and resident DCs in the skin-draining lymph nodes.…”

“…The targeting of this receptor is a viable and attractive strategy for the delivery of carbohydrate-containing imaging/diagnostic agents as well as the intracellular delivery of therapeutics for many infectious diseases, such as tuberculosis, pneumonia, HIV, and influenza . DC-SIGN and Langerin receptor (CD207) are two other mannose-binding CLRs. , Langerin receptor is mostly expressed on Langerhans cells (LC), which populate the skin epidermis and all stratified epithelia. It is also found on dermal DCs and resident DCs in the skin-draining lymph nodes.…”

Synthesis of glycopeptides and glycopeptide conjugates

“…While the higher valency conjugates showed an increase in affinity for the targeted receptors, this did not translate into improved presentation of the antigens to T-cells. 31,149 In a similar manner, stabilized ligands for the mannose-6phosphate receptor, in the form of mannose-6-phophonate (100), conjugated to epitopes derived from chicken ovalbumin (99), were produced (Fig. 14B).…”

Fc‐conjugated C‐type lectin receptors: Tools for understanding host–pathogen interactions

“…No binding by Fc MCL was detected on a range of glycan arrays (Graham et al, 2012;Maglinao et al, 2014) Langerin is a trimeric CLR, due to the coiled neck region, with a distinct glycan-binding pattern mostly resolved using bacterial expressed tagged proteins . The most recent study has demonstrated binding to bifunctional mannosylated oligosaccharides when presented in increasing copy number on a peptide scaffold (Li et al, 2020) et al, 2011). These studies show that Langerin specifically binds a 6'-sulfated galactose found in sulfated Le X -related sequences, high mannose, GlcNAcβGal/GalNAc, and fucose-containing antigens, but in contrast to the de Jong et al ( 2010) study no binding, in a β-glucan-dependent manner, was detected.…”