Xenograft - Revision history

Nnjm2 at 15:43, 22 October 2012

2012-10-22T15:43:43Z

← Older revision		Revision as of 15:43, 22 October 2012
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	~~=== Definition ===~~		A Xenograft is defined as the transplantation of a tissue or whole organ across [[Species\|species]]' <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>.

	A Xenograft is defined as the transplantation of a tissue or whole organ across [[species\|species]]' <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>.		The process has been done many times within research with xenografts between rats and mice common, however there are many problems surrounding the continued acceptance of a xenograft from a recipient. If these issues could be overcome then the possibilities are enourmous to both medicine and humanity as a whole; for one the crippling lack of donor organs would mean life to many on transplant waiting lists <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>.

	The process has been done many times within research with xenografts between rats and mice common, however there are many problems surrounding the continued acceptance of a xenograft from a recipient. If these issues could be overcome then the possibilities are enourmous to both medicine and humanity as a whole; for one the crippling lack of donor organs would mean life to many on transplant waiting lists <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>.

	=== Obstacles In Xenograft Usage ===		=== Obstacles In Xenograft Usage ===

	There are a few key obstacles within xenograft usage. Namely they are;		There are a few key obstacles within xenograft usage. Namely they are;

	#[[~~MHC_Molecules~~\|MHC]] Incompatibility And [[T cells\|T-Cells]]		#[[MHC Molecules\|MHC]] Incompatibility And [[T cells\|T-Cells]]
	#Other, Minor[[ Allo-antigens\|Allo-antigens]]		#Other, Minor[[Allo-antigens\|Allo-antigens]]

	Incompatibilities within the donor and recipient's [[~~MHC_Molecules~~\|Major]] and Minor Histocompatibility Complexes cause non-self specific T-cells to be activated that in turn activate the production of [[Antibody\|antibodies]] and the [[Complement\|complement]] and [[~~clotting~~ cascades\|clotting cascades]] against the graft (be it a xenograft or allograft, in this case the former.). Non-self specific T-cells are always produced by the [[~~immune~~ system\|immune system]] and as a result hemorrhaging of the Graft occurs rapidly <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref>. MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently [[~~anti~~-CD4\|anti-CD4]] and[[ ~~anti~~-CD8\| anti-CD8]] [[~~monoclonal~~ antibody\|monoclonal antibodies]] can be given to the recipient to overcome any MHC incompatibilities, thus prolonging the recipient's tolerance to the graft <ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref>. Anti-CD4 and anti-CD8 monoclonal antibodies have the added benefit of not suppressing the entirety of the recipient's immune system, as well as avoiding the need for T-cell depletion, so that the recipient is not vulnerable to oppurtunistic infections. However, T-cell mediated actions against a xenograft are still vastly complicated and, at the moment, untamed.		Incompatibilities within the donor and recipient's [[MHC Molecules\|Major]] and Minor Histocompatibility Complexes cause non-self specific T-cells to be activated that in turn activate the production of [[Antibody\|antibodies]] and the [[Complement\|complement]] and [[Clotting cascades\|clotting cascades]] against the graft (be it a xenograft or allograft, in this case the former.). Non-self specific T-cells are always produced by the [[Immune system\|immune system]] and as a result hemorrhaging of the Graft occurs rapidly <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref>. MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently [[Anti-CD4\|anti-CD4]] and[[Anti-CD8\| anti-CD8]] [[Monoclonal antibody\|monoclonal antibodies]] can be given to the recipient to overcome any MHC incompatibilities, thus prolonging the recipient's tolerance to the graft <ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref>. Anti-CD4 and anti-CD8 monoclonal antibodies have the added benefit of not suppressing the entirety of the recipient's immune system, as well as avoiding the need for T-cell depletion, so that the recipient is not vulnerable to oppurtunistic infections. However, T-cell mediated actions against a xenograft are still vastly complicated and, at the moment, untamed.

	Other minor [[~~antigen~~\|antigens]], for example the mammalian ubiquitous carbohydrate antigen α-Gal, have natural antibodies opposing them within primates. Pigs, theorised to be the most similar in organ size to humans (as well as being already farmed and harvested for their meat), unfortunately also have these carbohydrate antigens. When a xenograft from a Pig is placed into a human recipient these natural antibodies bind to the minor antigens (such as α-Gal) and are the cause of swift, hyperacute rejection. Such as with MHC incompatibility there have been developments to overcoming these antigens, the production of [[Transgenic\|transgenic]] pigs that express human minor antigens as well as the pig's natural α-Gal being a major step to overcoming this obstacle <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p658</ref>.		Other minor [[Antigen\|antigens]], for example the mammalian ubiquitous carbohydrate antigen α-Gal, have natural antibodies opposing them within primates. Pigs, theorised to be the most similar in organ size to humans (as well as being already farmed and harvested for their meat), unfortunately also have these carbohydrate antigens. When a xenograft from a Pig is placed into a human recipient these natural antibodies bind to the minor antigens (such as α-Gal) and are the cause of swift, hyperacute rejection. Such as with MHC incompatibility there have been developments to overcoming these antigens, the production of [[Transgenic\|transgenic]] pigs that express human minor antigens as well as the pig's natural α-Gal being a major step to overcoming this obstacle <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p658</ref>.

	=== References ===		=== References ===

	<references /><br>		<references /><br>

Nnjm2 at 15:43, 22 October 2012

2012-10-22T15:43:22Z

← Older revision		Revision as of 15:43, 22 October 2012
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	= ~~Xenograft<u></u>~~ =		=== Definition ===

	*<u>'''Definition'''</u>		A Xenograft is defined as the transplantation of a tissue or whole organ across [[species\|species]]' <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>.
	*<u>'''Obstacles In Xenograft ~~Usage''~~'</u>
	*<u>'''References'''</u>

	~~== Definition ==~~		The process has been done many times within research with xenografts between rats and mice common, however there are many problems surrounding the continued acceptance of a xenograft from a recipient. If these issues could be overcome then the possibilities are enourmous to both medicine and humanity as a whole; for one the crippling lack of donor organs would mean life to many on transplant waiting lists <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>.

	A Xenograft is defined as the transplantation of a tissue or whole organ across species'. <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>		=== Obstacles In Xenograft Usage ===

	~~ The process has been done many times within Research with Xenografts between rats and mice common, however there~~ are ~~many problems surrounding the continued acceptance of~~ a~~ ~~xenograft ~~from a recipient~~. ~~If these issues could be overcome then the possibilities ~~are ~~enourmous to both&nbsp~~;medicine and Humanity as a whole; for one the crippling lack of donor organs would mean life to many on Transplant waiting lists.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>		There are a few key obstacles within xenograft usage. Namely they are;

	~~== Obstacles In Xenograft Usage ==~~		#[[MHC_Molecules\|MHC]] Incompatibility And [[T cells\|T-Cells]]
			#Other, Minor[[ Allo-antigens\|Allo-antigens]]

	~~There are~~ a ~~few key obstacles within Xenograft usage~~. ~~Namely they~~ are;<br>1) MHC ~~Incompatibility And T~~-~~Cells~~<br>2) ~~Other~~, ~~Minor Alloantigens~~		Incompatibilities within the donor and recipient's [[MHC_Molecules\|Major]] and Minor Histocompatibility Complexes cause non-self specific T-cells to be activated that in turn activate the production of [[Antibody\|antibodies]] and the [[Complement\|complement]] and [[clotting cascades\|clotting cascades]] against the graft (be it a xenograft or allograft, in this case the former.). Non-self specific T-cells are always produced by the [[immune system\|immune system]] and as a result hemorrhaging of the Graft occurs rapidly <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref>. MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently [[anti-CD4\|anti-CD4]] and[[ anti-CD8\| anti-CD8]] [[monoclonal antibody\|monoclonal antibodies]] can be given to the recipient to overcome any MHC incompatibilities, thus prolonging the recipient's tolerance to the graft <ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref>. Anti-CD4 and anti-CD8 monoclonal antibodies have the added benefit of not suppressing the entirety of the recipient's immune system, as well as avoiding the need for T-cell depletion, so that the recipient is not vulnerable to oppurtunistic infections. However, T-cell mediated actions against a xenograft are still vastly complicated and, at the moment, untamed.

	~~Incompatibilities within~~ the ~~Donor and Recipient's Major and Minor Histocompatibility Complexes~~ ~~cause Non-self Specific T-Cells to be activated~~ ~~that~~ in ~~turn activate the production of~~ ~~Antibodies~~ and ~~the Complement and Clotting Cascades against the graft (Be it a Xenograft or Allograft~~, ~~in this case the former~~.~~). Non-self Specific T-Cells are always produced by the Immune System and as~~ ~~a result hemorrhaging~~ of the ~~Graft~~ ~~occurs rapidly.~~<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref> MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently anti-CD4 and anti-CD8 Monoclonal Antibodies can be given to the Recipient to overcome any MHC incompatibilities, thus prolonging the Recipient's tolerance to the graft.<ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref> Anti-CD4 and anti-CD8 Monoclonal Antibodies have the added benefit of not suppressing the entirety of the Recipient's Immune System, as well as avoiding the need for T-Cell Depletion, so that the Recipient is not vulnerable to oppurtunistic infections. However, T-Cell mediated actions against a Xenograft are still vastly complicated and, at the moment, untamed.		Other minor [[antigen\|antigens]], for example the mammalian ubiquitous carbohydrate antigen α-Gal, have natural antibodies opposing them within primates. Pigs, theorised to be the most similar in organ size to humans (as well as being already farmed and harvested for their meat), unfortunately also have these carbohydrate antigens. When a xenograft from a Pig is placed into a human recipient these natural antibodies bind to the minor antigens (such as α-Gal) and are the cause of swift, hyperacute rejection. Such as with MHC incompatibility there have been developments to overcoming these antigens, the production of [[Transgenic\|transgenic]] pigs that express human minor antigens as well as the pig's natural α-Gal being a major step to overcoming this obstacle <ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p658</ref>.

	Other Minor Antigens, for example the mammalian ubiquitous Carbohydrate Antigen α-Gal, have natural antibodies opposing them within primates . Pigs, theorised to be the most similar in organ size to Humans (As well as being already farmed and harvested for their meat), unfortunately also have these Carbohydrate Antigens. When a Xenograft from a Pig is placed into a Human Recipient these natural Antibodies bind to the Minor Antigens (such as α-Gal) and are the cause of swift, hyperacute rejection. Such as with MHC Incompatibility there have been developments to overcoming these Antigens, the production of Transgenic Pigs that express Human minor antigens as well as the Pig's natural α-Gal being a major step to overcoming this obstacle.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p658</ref>		=== References ===

	~~== References ==~~		<references /><br>

	<references />

	<~~references />~~

	~~<references />~~

	~~<references />~~

	~~<references /~~>

110096216 at 14:46, 22 October 2012

2012-10-22T14:46:46Z

← Older revision		Revision as of 14:46, 22 October 2012
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	== Definition ==		== Definition ==

	A Xenograft is defined as the transplantation of a tissue or whole organ across species'. <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>		A Xenograft is defined as the transplantation of a tissue or whole organ across species'. <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>

	The process has been done many times within Research with Xenografts between rats and mice common, however there are many problems surrounding the continued acceptance of a xenograft from a recipient. If these issues could be overcome then the possibilities are enourmous to both medicine and Humanity as a whole; for one the crippling lack of donor organs would mean life to many on Transplant waiting lists.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>		The process has been done many times within Research with Xenografts between rats and mice common, however there are many problems surrounding the continued acceptance of a xenograft from a recipient. If these issues could be overcome then the possibilities are enourmous to both medicine and Humanity as a whole; for one the crippling lack of donor organs would mean life to many on Transplant waiting lists.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>
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	== Obstacles In Xenograft Usage ==		== Obstacles In Xenograft Usage ==

	There are a few key obstacles within Xenograft usage. Namely they are;<br>1) MHC Incompatibility<br>2) Other, Minor Alloantigens		There are a few key obstacles within Xenograft usage. Namely they are;<br>1) MHC Incompatibility And T-Cells<br>2) Other, Minor Alloantigens

	Incompatibilities within the Donor and Recipient's Major and Minor Histocompatibility Complexes cause Non-self Specific T-Cells to be activated that in turn activate the production of ~~Alloantibodies~~ and the Complement and Clotting Cascades against the graft (Be it a Xenograft or Allograft, in this case the former.). Non-self Specific T-Cells are always produced by the Immune System and as a result hemorrhaging of the Graft occurs rapidly.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref> MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently anti-CD4 and anti-CD8 Monoclonal Antibodies can be given to the Recipient to overcome any MHC incompatibilities, thus prolonging the Recipient's tolerance to the graft.<ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref> Anti-CD4 and anti-CD8 Monoclonal Antibodies have the added benefit of not suppressing the entirety of the Recipient's Immune System, as well as avoiding the need for T-Cell Depletion, so that the Recipient is not vulnerable to oppurtunistic infections.		Incompatibilities within the Donor and Recipient's Major and Minor Histocompatibility Complexes cause Non-self Specific T-Cells to be activated that in turn activate the production of Antibodies and the Complement and Clotting Cascades against the graft (Be it a Xenograft or Allograft, in this case the former.). Non-self Specific T-Cells are always produced by the Immune System and as a result hemorrhaging of the Graft occurs rapidly.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref> MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently anti-CD4 and anti-CD8 Monoclonal Antibodies can be given to the Recipient to overcome any MHC incompatibilities, thus prolonging the Recipient's tolerance to the graft.<ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref> Anti-CD4 and anti-CD8 Monoclonal Antibodies have the added benefit of not suppressing the entirety of the Recipient's Immune System, as well as avoiding the need for T-Cell Depletion, so that the Recipient is not vulnerable to oppurtunistic infections. However, T-Cell mediated actions against a Xenograft are still vastly complicated and, at the moment, untamed.

	Other Minor ~~Alloantigens~~, for example the mammalian ubiquitous Carbohydrate Antigen α-Gal, have natural antibodies ~~against~~ them within primates		Other Minor Antigens, for example the mammalian ubiquitous Carbohydrate Antigen α-Gal, have natural antibodies opposing them within primates . Pigs, theorised to be the most similar in organ size to Humans (As well as being already farmed and harvested for their meat), unfortunately also have these Carbohydrate Antigens. When a Xenograft from a Pig is placed into a Human Recipient these natural Antibodies bind to the Minor Antigens (such as α-Gal) and are the cause of swift, hyperacute rejection. Such as with MHC Incompatibility there have been developments to overcoming these Antigens, the production of Transgenic Pigs that express Human minor antigens as well as the Pig's natural α-Gal being a major step to overcoming this obstacle.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p658</ref>

	== References ==		== References ==

			<references />

	<references />		<references />

110096216: Created page with "= Xenograft = '''Definition''' '''Obstacles In Xenograft Usage''' *'''References''' == Definition == A Xenograft is defined as the transplant..."

2012-10-22T14:05:53Z

Created page with "= Xenograft = *'''Definition''' *'''Obstacles In Xenograft Usage''' *'''References''' == Definition == A Xenograft is defined as the transplant..."

New page

= Xenograft =

*'''Definition'''
*'''Obstacles In Xenograft Usage'''
*'''References'''

== Definition ==

A Xenograft is defined as the transplantation of a tissue or whole organ across species'. <ref>Game, DS. (2001 ). Rejection mechanisms in transplantation.. Wien Klin Wochenschr.. 113 (20-21), 832-8.</ref>

 The process has been done many times within Research with Xenografts between rats and mice common, however there are many problems surrounding the continued acceptance of a xenograft from a recipient. If these issues could be overcome then the possibilities are enourmous to both medicine and Humanity as a whole; for one the crippling lack of donor organs would mean life to many on Transplant waiting lists.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.657-658</ref>

== Obstacles In Xenograft Usage ==

There are a few key obstacles within Xenograft usage. Namely they are; 1) MHC Incompatibility 2) Other, Minor Alloantigens

Incompatibilities within the Donor and Recipient's Major and Minor Histocompatibility Complexes cause Non-self Specific T-Cells to be activated that in turn activate the production of Alloantibodies and the Complement and Clotting Cascades against the graft (Be it a Xenograft or Allograft, in this case the former.). Non-self Specific T-Cells are always produced by the Immune System and as a result hemorrhaging of the Graft occurs rapidly.<ref>Murphy, K (2012). Janeway's Immunobiology. 8th ed. New York: Garland Sciences. p.652-654, 657</ref> MHC Incompatobility is not as much of a problem as it was in the past however, Immuno-suppressent drugs and more recently anti-CD4 and anti-CD8 Monoclonal Antibodies can be given to the Recipient to overcome any MHC incompatibilities, thus prolonging the Recipient's tolerance to the graft.<ref>Zonghua Chen. (1992). Tolerance in the mouse to major histocompatibility complex-mismatched heart allografts, and to rat heart xenografts, using monoclonal antibodies to CD4 and CD8. European Journal of Immunology. 22 (3), p805-810. DOI: 10.1002/eji.1830220326</ref> Anti-CD4 and anti-CD8 Monoclonal Antibodies have the added benefit of not suppressing the entirety of the Recipient's Immune System, as well as avoiding the need for T-Cell Depletion, so that the Recipient is not vulnerable to oppurtunistic infections. 

 Other Minor Alloantigens, for example the mammalian ubiquitous Carbohydrate Antigen α-Gal, have natural antibodies against them within primates  

== References ==

<references />

<references />

<references />

<references />

Xenograft - Revision history

Nnjm2 at 15:43, 22 October 2012

Nnjm2 at 15:43, 22 October 2012

110096216 at 14:46, 22 October 2012

110096216: Created page with "= Xenograft = *'''Definition''' *'''Obstacles In Xenograft Usage''' *'''References''' == Definition == A Xenograft is defined as the transplant..."

110096216: Created page with "= Xenograft = '''Definition''' '''Obstacles In Xenograft Usage''' *'''References''' == Definition == A Xenograft is defined as the transplant..."