Foot-and-mouth disease virus particles inactivated with binary ethylenimine are efficiently internalized into cultured cells.
Conventional foot-and-mouth disease (FMD) vaccines are produced from virus grown in cell culture that is chemically inactivated by using binary ethylenimide (BEI). Here, we show that BEI treatment preserves both the architecture of FMDV particles, as inactivated viral particles showed by electron microscopy characteristics similar to those of infectious virions, as well as the general features of infectious virus internalization. Binding of inactivated particles to BHK-21 cells was blocked by preincubation with either a FMDV-specific monoclonal antibody or a synthetic peptide spanning the integrin-binding viral motif Arg-Gly-Asp (RGD). In addition, these particles were internalized into cultured cells through endocytosis, being directed to early endosomes, as indicated by their colocalization with the marker protein Rab5. When purified BEI-inactivated virions were labelled and their interaction with live cultured cells analyzed by time-lapse fluorescence microscopy, a major subpopulation of virus particles, about 80%, was shown to undergo internalization into a static endosome population, insensitive to the microtubule depolymerization exerted by nocodazole, while the remaining subpopulation (about 20%) was dynamic and sensitive to this drug. Thus, BEI-inactivated particles provide an interesting tool to study early steps in FMDV-cell interactions enabling a distinction between FMDV internalization and productive infection. Possible implications for FMDV immune response elicited following vaccine administration are discussed.
Centro de Biología Molecular "Severo Ochoa" (CSIC-UAM), Cantoblanco 28049, Madrid, Spain.
Miguel A
MA
Martín-Acebes
Angela
A
Vázquez-Calvo
Mónica
M
González-Magaldi
Francisco
F
Sobrino
D000818:Animals; D001388:Aziridines / Q000494:pharmacology*; D002478:Cells, Cultured; D006224:Cricetinae; D004202:Disinfectants / Q000494:pharmacology*; D004705:Endocytosis; D011992:Endosomes / Q000821:virology; D029544:Foot-and-Mouth Disease Virus / Q000187:drug effects* / Q000502:physiology* / Q000648:ultrastructure; D008854:Microscopy, Electron; D008856:Microscopy, Fluorescence; D059008:Time-Lapse Imaging; D014771:Virion / Q000187:drug effects / Q000648:ultrastructure; D053586:Virus Internalization
D001388:Aziridines; D004202:Disinfectants; C033132:aziridine