Infection

Viral entry into host cells is facilitated by the glycoprotein peplomers on the virion surface. The asialoglycoprotein receptor of hepatocytes has been shown to be the receptor utilized by Marburg virus for entry into hepatocytes, but there is evidence that a number of other receptors, such as folate receptor-a and C-type lectins, on different cell types can also interact with the GP peplomers to promote viral entry. Ebola virus has also been associated with antibody-dependant enhancement, by which antibodies to virion surface proteins actually enhance the infectivity of the virus through interactions with Fc receptors of phagocytic cells, facilitating the entry and infection of these cells by the virus. This unfortunate consequence of the immune response is of critical consideration to vaccine design, as a vaccine that promotes the production of this specific subset of antibodies would actually accelerate infection rather than being protective. (click image for bigger version)

Following surface attachment, the virion enters the cell via endocytosis, and the viral envelope and host membrane fuse, releasing the nucleocapsid into the cell. Before protein synthesis can begin, the negative-sense RNA genome must first be transcribed into positive-sense mRNA, which can be detected by several hours after infection. Accumulated mRNA transcripts are translated into protein, until a build-up of viral protein initiates a switch to genome replication. The two processes of translation and genomic replication continue until an equilibrium in reached, and full-length genomes are encapsulated to produce new viral particles.

Nucleocapsids are brought into proximity with the plasma membrane, probably by association with VP40. Nucleocapsids become enveloped by host plasma membrane, and bud from infected cells in large quantities.

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This page last updated: 14 April 2004.