Baert, Kim

Cox, Eric

De Geest, Bruno

Devriendt, Bert

Dierendonck, Marijke

Favoreel, Herman

Remon, Jean Paul

English

Ghent University Academic Bibliography

Abstract template IPVS Belgian branch  Oral presentation      /    Poster   	  Biomimetic	  polyelectrolyte	  microparticles	  facilitate	  antigen	  presentation	  by	  porcine	  dendritic	  cells	  	  Bert	  DEVRIENDT1,*,	  Kim	  BAERT1,	  Marijke	  DIERENDONCK2,	  Herman	  FAVOREEL1,	  Jean	  Paul	  REMON2,	  Bruno	  G.	  DE	  GEEST2,	  Eric	  COX1	  	  	  1Laboratory	   of	   Immunology,	   Faculty	   of	   Veterinary	  Medicine,	  Ghent	  University,	  Merelbeke;	   2Laboratory	   of	   Pharmaceutical	  Technology,	  Department	  of	  Pharmaceutics,	  Faculty	  of	  Pharmaceutical	  Sciences,	  Ghent	  University,	  Ghent.	  	  Introduction	  Vaccination	   is	   regarded	   as	   the	   most	   efficient	   and	  cost-­‐effective	   way	   to	   prevent	   infectious	   diseases.	  Vaccine	   design	   nowadays	   focuses	   on	   the	  implementation	   of	   safer	   recombinant	   subunit	  vaccines.	   However,	   these	   recombinant	   subunit	  antigens	   are	   often	   poor	   immunogens	   and	   several	  strategies	   are	   currently	   under	   investigation	   to	  enhance	   their	   immunogenicity.	   The	   encapsulation	  of	   the	   antigens	   in	   biodegradable	   microparticulate	  delivery	   systems	   seems	   a	   promising	   strategy	   to	  boost	  their	  immunogenicity1.	  Here,	  we	  evaluate	  the	  capacity	   of	   polyelectrolyte	  microparticles	   (PECMs),	  fabricated	   by	   single	   step	   spray-­‐drying,	   to	   deliver	  antigens	   to	   porcine	   dendritic	   cells	   (DCs)	   and	   how	  these	   particles	   affect	   their	   functional	   maturation	  (DCs).	   As	   clinically	   relevant	   model	   antigen	   F4	  fimbriae,	   a	   bacterial	   adhesin	   purified	   from	   a	  porcine-­‐specific	  enterotoxigenic	  E.	  coli	  (ETEC)	  strain,	  was	  chosen.	  	  Materials	  and	  methods	  PECMs	  were	  loaded	  with	  either	  BSA-­‐FITC	  or	  the	  F4	  fimbriae	   by	   co-­‐spray-­‐drying	   these	   antigens	   with	  the	   PECM	   constituents:	   the	   polyelectrolytes	  dextran-­‐sulphate	   and	   poly-­‐L-­‐arginine	   and	   the	  sacrificial	  template	  mannitol.	  PBMCs	  were	  isolated	  from	   blood	   by	   density	   gradient	   centrifugation.	  CD172a+	   monocytes	   were	   further	   enriched	   by	  positive	   immunomagnetic	   bead	   selection	   (MACS)	  and	  cultured	   for	  4	  days	  with	   recombinant	  porcine	  (rp)	   IL-­‐4	   and	   rpGM-­‐CSF	   to	   generate	   porcine	  monocyte-­‐derived	   DCs	   (MoDCs).	   These	   in	   vitro	  generated	  immature	  MoDCs	  were	  incubated	  for	  24	  h	  with	  LPS	  (1	  μg),	  F4	  fimbriae	  (1.0	  and	  0.1	  μg)	  and	  F4-­‐fimbriae-­‐loaded	   polyelectrolyte	   microparticles	  (F4-­‐PECM;	   1.0	   and	   0.1	   μg	   encapsulated	   antigen)	  and	  the	  phenotypical	  and	  functional	  DC	  maturation	  was	   assessed	   by	   confocal	   and	   live	   cell	   imaging,	  flow	   cytometry,	   T-­‐cell	   proliferation	   assays	   and	  porcine-­‐specific	  cytokine	  ELISAs.	  	  	  Results	  In	   confocal	   images	  we	   detected	  multiple	   particles	  per	   cell	   in	   >80%	   of	   the	   examined	   DCs,	   indicating	  that	   the	   resulting	   antigen-­‐loaded	   PECMs	   were	  efficiently	   internalised	   by	   porcine	   MoDCs.	   F4-­‐PECMs	   enhanced	   CD40	   and	   CD25	   surface	  expression	   by	   DCs	   and	   this	   phenotypical	  maturation	  correlated	  with	  an	   increased	  secretion	  of	   IL-­‐6	   and	   IL-­‐1β.	   More	   importantly,	   F4-­‐PECMs	  enhanced	   both	   the	   T-­‐cell	   stimulatory	   ability	   and	  antigen	   presentation	   capacity	   to	   CD6+	   T-­‐cells	   of	  MoDCs.	  Moreover,	  PECMs	  efficiently	  promoted	  the	  CD8+	   T-­‐cell	   stimulatory	   activity	   of	   dendritic	   cells,	  indicating	  an	  enhanced	  ability	  of	  the	  DCs	  to	  cross-­‐present	  the	  encapsulated	  antigens	  via	  MHCI.	  	  	  Discussion	  and	  conclusions	  In	   conclusion,	   single	   step	   spray-­‐dried	   antigen-­‐loaded	   polyelectrolyte	   microparticles	   efficiently	  enhanced	  the	  functional	  maturation	  and	  increased	  the	   cross-­‐presentation	   ability	   of	   porcine	   DCs.	  Interestingly,	   the	  elevated	   IL-­‐6	  and	   IL-­‐1β	  secretion	  could	  hint	  at	  the	  capacity	  of	  PECM-­‐stimulated	  DCs	  to	   drive	   T-­‐cell	   polarisation	   towards	   a	   Th17	  phenotype,	   while	   higher	   IL-­‐1β	   levels	   could	   also	  indicate	   inflammasome	   activation.	   Our	   results	  confirm	   recent	   data	   obtained	   in	   rodent	   models	  that	   these	   PECMs	   boost	   the	   immunogenicity	   of	  vaccine	  antigens2.	  In	  addition,	  this	  antigen	  delivery	  system	   allows	   not	   only	   the	   co-­‐encapsulation	   of	  immune	  potentiators,	  such	  as	  PRR	  ligands,	  but	  also	  the	  functionalisation	  of	  the	  microparticles’	  surface	  with	   targeting	   ligands	   to	   enhance	   the	   delivery	   of	  these	   carrier	   systems	   to	   the	   immune	   system.	  Our	  results	   could	   accelerate	   the	   development	   of	  veterinary	   and	   human	   subunit	   vaccines	   based	   on	  polyelectrolyte	   microparticulate	   delivery	   systems	  to	   combat	   a	   variety	   of	   extra-­‐	   and	   intracellular	  pathogens.	  	  References	  1De	  Koker	  et	  al.,	  2011,	  Chem	  Soc	  Rev	  40:320-­‐39	  	  2Dierendonck	  et	  al.,	  2011,	  ASC	  Nano,	  5:6886-­‐93X X Abstract template IPVS Belgian branch  	  	  

Biomimetic polyelectrolyte microparticles facilitate antigen presentation by porcine dendritic cells

https://biblio.ugent.be/publication/3133810/file/3133817

Biomimetic polyelectrolyte microparticles facilitate antigen presentation by porcine dendritic cells

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Ghent University Academic Bibliography