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Vaccine

2017-10-23T11:52:59Z

160091434:

A [[Vaccine|vaccine will]] allow an organism's [[Immune system|immune system]] to develop an active immunity against a certain [[Pathogen|pathogen]] <ref>NHS.04/04/2014, How vaccines work, [Online]Available at: http://www.nhs.uk/conditions/vaccinations/pages/how-vaccines-work.aspx,[Accessed - 27/11/2014]</ref>.

Vaccines are prepared from causative agent of a disease, or a synthetic substitute treated to act as an antigen without inducing the disease.

The vaccine will mimic the process of a natural [[Infection|infection]], however, the [[Organism|organism]] will not experience the effects of being infected by the [[Pathogen|pathogen]] <ref>U.S. Department of Health and Human Services.23/7/13, How Vaccines Work, [Online]Available at: http://www.vaccines.gov/more_info/work/ ,[Accessed - 27/11/2014]</ref>.

In order to safely develop [[Active immunity|active immunity]], the [[Pathogen|pathogen]] must first be altered in some way so that it will not be damaging to the target organism. 

Processes that will render the [[Pathogen|pathogen]] harmless include:

*"Weakening, or "attenuating", the [[Pathogen|pathogen]] by growing it repeatedly to select a strain that's less dangerous – [[MMR vaccine|MMR vaccines]] are attenuated.
*Taking out the part of the [[Pathogen|pathogen]] that causes the immune response and using this in the vaccine –the [[Hib vaccine|Hib vaccine]] is made in this way.
*Using the [[Toxin|toxin]] that the [[Pathogen|pathogen]] makes and inactivating it – this is how the [[Tetanus vaccine|tetanus vaccine]] is produced<ref>NHS.04/04/2014, How vaccines work, [Online]Available at: http://www.nhs.uk/conditions/vaccinations/pages/how-vaccines-work.aspx,[Accessed - 27/11/2014]</ref>. 

The vaccine (altered pathogens) is then inserted into the target organism. Its [[Immune system|Immune system]] will respond as the vaccine is seen as a threat. The[[Immune system|immune response]] will behave naturally and the vaccine will be destroyed, however the [[Memory T cells|Memory T]] and [[Memory B cells|Memory B]] cells will remember the pathogen's [[Antigen|antigen]] structure <ref>U.S. Department of Health and Human Services.23/7/13, How Vaccines Work, [Online]Available at: http://www.vaccines.gov/more_info/work/ ,[Accessed - 27/11/2014]</ref>.

This will allow a rapid immune response if the organism ever comes into contact with the [[Pathogen|pathogen]] again <ref>U.S. Department of Health and Human Services.23/7/13, How Vaccines Work, [Online]Available at: http://www.vaccines.gov/more_info/work/ ,[Accessed - 27/11/2014]</ref>. However for [[T lymphocytes|T]] and [[B-Lymphocyte|B lymphocytes]] to develop it can take a few weeks, therefore it is possible that if someone is infected with the pathogen within a few weeks of getting them vaccinated it is possible for them to have symptoms of the disease <ref>http://www.cdc.gov/vaccines/hcp/patient-ed/conversations/downloads/vacsafe-understand-color-office.pdf</ref> <ref>http://www.cdc.gov/vaccines/hcp/patient-ed/conversations/downloads/vacsafe-understand-color-office.pdf</ref>.

Conjugate vaccines have been designed to immunise young children against ''Haemophilus influenzae'' type b (Hib). Hib contains a polysaccharide capsule made of polyribosyl ribitol phosphate (PRP) which is a T-independent [[Antigen|antigen]] (thymus-independent) and is not immunogenic in children under the age of 4; therefore conjugate vaccines have been created to protect these individuals. The PRP capsule is covalently linked to a carrier protein, which attracts [[T-cells|T cell]] help and, as a result, anti-PRP [[Antibodies|antibodies]] are produced. This means a second encounter of this polysaccharide on Hib would induce a rapid reaction to clear and destroy this pathogen<ref>Dominic F Kelly, E Richard Moxon, Andrew J Pollard. (2004) Haemophilus influenzae type b conjugate vaccines. Immunology. Vol.113(2), 163-174.</ref>. 

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Null mutation

2017-10-19T15:11:20Z

160091434:

A null [[Mutation|mutation]] is when the functionality of a protein completely ceases to work due to a [[Nucleotide|nucleotide]] change. This would result in a truncated protein.  

Vibrio cholerae

2016-11-15T12:00:07Z

160091434:

''Vibreo cholerae'' is a gram-negative bacterium which is both fermentative and oxidative in its [[Metabolism|metabolism]]. Its movement is enbled by a single polar [[Flagellum|flagellum]] <ref>www.textbookofbacteriology.net,2008,Vibreo cholerae and Asiatic cholera, Kenneth Todar</ref>.

There are hundreds of strains of ''V. cholerae'', and only those which are infected by a mobile [[Bacteriophage|bacteriophage]] cause human disease such as the epidemic diarrheal disease, cholera<ref name="null">Alberts B, Johnson A, Lewis J, Morgan D, Raff M, Roberts K, Walter P. Molecular Biology of the Cell. 6th Ed, Garland Science, Taylor and Francis Group. 2015; Page 1269-1270</ref>. ''V. cholerae'' causes [[Cholera|cholera]] by producing [[Cholera toxin|cholera toxins ]](CT) which consists of 2 subunits: A and B. The A subunit contains enzymatic activity and the B subunit binds to a cell-surface receptor called GM1 on intestinal epithelial cells<ref>Alberts B, Jonhson A, Lewis J, Morgan D, Raff M, Roberts K, Walter P. Molecular Biology of the Cell. 6th Ed, Garland Science, Taylor and Francis Group. 2015; Page 576</ref>.

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Vibrio cholerae

2016-11-15T11:59:27Z

160091434: I have added more text to expand on the topic and to give more detail.

''Vibreo cholerae'' is a gram-negative bacterium which is both fermentative and oxidative in its [[Metabolism|metabolism]]. Its movement is enbled by a single polar [[Flagellum|flagellum]] <ref>www.textbookofbacteriology.net,2008,Vibreo cholerae and Asiatic cholera, Kenneth Todar</ref>.

There are hundreds of strains of ''V. cholerae'', and only those which are infected by a mobile [[Bacteriophage|bacteriophage]] cause human disease such as the epidemic diarrheal disease, cholera<ref name="null">Alberts B, Johnson A, Lewis J, Morgan D, Raff M, Roberts K, Walter P. Molecular Biology of the Cell. 6th Ed, Garland Science, Taylor and Francis Group. 2015; Page 1269-1270</ref>. ''V. cholerae'' causes [[Cholera|cholera]] by producing [[Cholera_toxin|cholera toxins ]](CT) which consist of 2 subunits: A and B. The A subunit contains enzymatic activity and the B subunit binds to a cell-surface receptor called GM1 on intestinal epithelial cells<ref>Alberts B, Jonhson A, Lewis J, Morgan D, Raff M, Roberts K, Walter P. Molecular Biology of the Cell. 6th Ed, Garland Science, Taylor and Francis Group. 2015; Page 576</ref>.

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