Promotion of opsonization by antibodies and phagocytosis of Gram-positive bacteria by a bifunctional polyacrylamide.
This paper describes the application of a bifunctional polyacrylamide (pA-V-F) presenting both vancomycin and fluorescein groups, to modify the surfaces of multiple species of Gram-positive bacteria (Staphylococcus aureus, Staphylococcus epidermidis, Streptococcus pneumoniae, and Enterococcus faecalis) to control molecular recognition of these surfaces. The vancomycin groups allowed the specific recognition of a structural component of the bacterial cell wall: peptides terminated in D-Ala-D-Ala. The fluorescein groups allowed the imaging of binding of polymer to the surfaces of bacteria by fluorescence, and are representative, low molecular weight haptens; their recognition by anti-fluorescein antibodies provides proof-of-principle that bifunctional polymers can be used to introduce haptens onto the surface of the bacteria. Flow cytometry revealed that polymer-labeled S. aureus and S. pneumoniae were opsonized by anti-fluorescein antibodies approximately 20-fold more than were untreated bacteria; nearly all ( approximately 92%) polymer-labeled S. aureus, and a large (76%) fraction of polymer-labeled S. pneumoniae were opsonized. The bound antibodies then promoted phagocytosis of the bacteria by cultured J774 macrophage-like cells. Flow cytometry revealed that macrophages ingested S. aureus decorated with the polymer-antibody complexes approximately 2-fold more efficiently than S. aureus in control groups, in spite of the high background (caused by efficient antibody-independent ingestion of S. aureus by macrophages). This paper, thus, demonstrates the ability of a bifunctional polymer to carry out three distinct functions based on polyvalent molecular recognition: (i) recognition of the surface of Gram-positive bacteria, (ii) modification of this surface to generate specific binding sites recognized by an antibody, and (iii) promotion of phagocytosis of the opsonized bacteria.
Krishnamurthy
Vijay M
VM
Department of Chemistry and Chemical Biology, Harvard University, 12 Oxford Street, Cambridge, MA 02138, USA.
Quinton
Lee J
LJ
Estroff
Lara A
LA
Metallo
Steven J
SJ
Isaacs
Jessica M
JM
Mizgerd
Joseph P
JP
Whitesides
George M
GM
D000180:Acrylic Resins / Q000737:chemistry / Q000494:pharmacology*; D000818:Animals; D000907:Antibodies, Bacterial / Q000378:metabolism*; D001672:Biocompatible Materials / Q000737:chemistry / Q000494:pharmacology*; D002460:Cell Line; D013293:Enterococcus faecalis / Q000187:drug effects / Q000276:immunology; D006094:Gram-Positive Bacteria / Q000187:drug effects* / Q000276:immunology*; D066298:In Vitro Techniques; D008264:Macrophages / Q000187:drug effects / Q000276:immunology; D008422:Materials Testing; D051379:Mice; D008856:Microscopy, Fluorescence; D009895:Opsonin Proteins / Q000378:metabolism*; D010587:Phagocytosis / Q000187:drug effects; D013211:Staphylococcus aureus / Q000187:drug effects / Q000276:immunology; D013212:Staphylococcus epidermidis / Q000187:drug effects / Q000276:immunology; D000099166:Polyacrylamides
D000180:Acrylic Resins; D000907:Antibodies, Bacterial; D001672:Biocompatible Materials; D009895:Opsonin Proteins; D000099166:Polyacrylamides