Enhancement of polymeric immunoglobulin receptor transcytosis by biparatopic VHH.
The polymeric immunoglobulin receptor (pIgR) ensures the transport of dimeric immunoglobulin A (dIgA) and pentameric immunoglobulin M (pIgM) across epithelia to the mucosal layer of for example the intestines and the lungs via transcytosis. Per day the human pIgR mediates the excretion of 2 to 5 grams of dIgA into the mucosa of luminal organs. This system could prove useful for therapies aiming at excretion of compounds into the mucosa. Here we investigated the use of the variable domain of camelid derived heavy chain only antibodies, also known as VHHs or Nanobodies®, targeting the human pIgR, as a transport system across epithelial cells. We show that VHHs directed against the human pIgR are able to bind the receptor with high affinity (∼1 nM) and that they compete with the natural ligand, dIgA. In a transcytosis assay both native and phage-bound VHH were only able to get across polarized MDCK cells that express the human pIgR gene in a basolateral to apical fashion. Indicating that the VHHs are able to translocate across epithelia and to take along large particles of cargo. Furthermore, by making multivalent VHHs we were able to enhance the transport of the compounds both in a MDCK-hpIgR and Caco-2 cell system, probably by inducing receptor clustering. These results show that VHHs can be used as a carrier system to exploit the human pIgR transcytotic system and that multivalent compounds are able to significantly enhance the transport across epithelial monolayers.
Biomolecular Imaging, Department of Biology, Faculty of Science, Utrecht University, Utrecht, The Netherlands.
Chris D
CD
Emmerson
Els J
EJ
van der Vlist
Myrthe R
MR
Braam
Peter
P
Vanlandschoot
Pascal
P
Merchiers
Hans J W
HJ
de Haard
C Theo
CT
Verrips
Paul M P
PM
van Bergen en Henegouwen
Edward
E
Dolk
D000818:Animals; D018938:Caco-2 Cells; D002161:Camelids, New World; D016764:Cell Polarity; D004285:Dogs; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism; D018604:Epitope Mapping; D006801:Humans; D007143:Immunoglobulin Heavy Chains / Q000378:metabolism*; D007135:Immunoglobulin Variable Region / Q000378:metabolism*; D011485:Protein Binding; D019056:Receptors, Polymeric Immunoglobulin / Q000378:metabolism*; D015203:Reproducibility of Results; D057900:Transcytosis
D007143:Immunoglobulin Heavy Chains; D007135:Immunoglobulin Variable Region; D019056:Receptors, Polymeric Immunoglobulin