5,582
edits
Changes
Jump to navigation
Jump to search
Immune Responses to Viral Infections (view source)
Revision as of 08:47, 21 October 2010
, 08:47, 21 October 2010→Adaptive immunity
==Adaptive immunity==
==Adaptive immunity==
The importance of the adaptive immune system in responding to viral infections can be demonstrated using athymic 'nude' mice, which lack mature T cells. These mice show particular vulnerability to the herpes simplex virus, resulting in death when infection reaches the CNS. However transfer of antigen-specific T cells to the mice shortly after infection leads to recovery.
The importance of the adaptive immune system in responding to viral infections can be demonstrated using athymic 'nude' mice, which lack mature T cells. These mice show particular vulnerability to the herpes simplex virus, resulting in death when infection reaches the CNS. However transfer of antigen-specific T cells to the mice shortly after infection leads to recovery.
[[Image:B Cell viral response.jpg|thumb|right|200px|B Cell Immunity to Viruses - B. Catchpole, RVC 2008]]
*Antibodies- these are particularly important in preventing the spread of the virus in the bloodstream
*Antibodies- these are particularly important in preventing the spread of the virus in the bloodstream
**[[IgA]] production is increased at mucosal surfaces- helps prevent reinfection
**[[IgA]] production is increased at mucosal surfaces- helps prevent reinfection
**Although antibodies that target any viral protein can be produced, only those directed against proteins found in the virion envelope or infected cell membrane will be effective
**Although antibodies that target any viral protein can be produced, only those directed against proteins found in the virion envelope or infected cell membrane will be effective
***aid lysis of infected cells
***aid lysis of infected cells
***aid opsonisation of free virus or infected cells for phagocytosis
***aid opsonisation of free virus or infected cells for phagocytosis
[[Image:T Cell viral response.jpg|thumb|right|200px|T Cell Immunity to Viruses - B. Catchpole, RVC 2008]]
*T cells
*T cells
**CD8+ cytotoxic T cells are particularly important as nearly all the cells in the body express MHC class I. They tend to focus at the site of viral replication and destroy virus-infected cells.
**CD8+ cytotoxic T cells are particularly important as nearly all the cells in the body express MHC class I. They tend to focus at the site of viral replication and destroy virus-infected cells.
**CD4+ T cells are important in the recruitment of macrophages, using cytokines such as IFN-γ and TNF, and the induction of CD8+ cytotoxic T cells
**CD4+ T cells are important in the recruitment of macrophages, using cytokines such as IFN-γ and TNF, and the induction of CD8+ cytotoxic T cells