MVA-B
Encyclopedia
MVA-B, or Modified Vaccinia Ankara B, is a particular HIV vaccine
created to give immune resistance to infection by the HIV virus. It was developed by a team of Spanish
researchers at the Spanish National Research Council's Biotechnology National Centre headed by Dr. Mariano Esteban. The vaccine is based on the Modified vaccinia Ankara
(MVA) virus used during the 1970s to help eradicate the smallpox virus. The B in the name "refers to HIV-B, the most common HIV subtype in Europe". It has been stated by Dr. Esteban that, in the future, the vaccine could potentially reduce the virulence
of HIV to a "minor chronic infection akin to herpes".
in 2008 against the Simian immunodeficiency virus
(SIV) and it was found to be successful in every case in creating an immune system response to SIV infection.
and had no results. Of the other twenty-four individuals, twenty-two exhibited a "very strong immunological response against the HIV virus", bringing the success rate of the testing to 92%. The immune reaction that the successful testers exhibited lasted for a period close to a year for 85% of the testers, who had no "significant secondary effects". It was also shown that, from blood tests in the 48th week after administration of the vaccine, in 72.5% of the volunteers, "specific antibodies" had formed to combat possible HIV infection. Specifically, the blood tests revealed that the immune system production of CD4+ T lymphocytes and CD8+ T lymphocytes
were at 38.5% and 69.2% each for the testers given the vaccine, while the amounts in the group given the placebo remained at 0%.
The next step with the vaccine within Phase I testing is to conduct a trial with HIV-positive testers, in order to determine if there is a "therapeutical effect of the vaccine" on those already infected with the virus.
from the HIV genome, specifically those titled Gag
, Pol
, Nef
and Env
.
HIV vaccine
An HIV vaccine that protects vaccinated individuals from HIV infection is the goal of many HIV research programmes. Currently, there is no effective vaccine against HIV, the virus that causes AIDS...
created to give immune resistance to infection by the HIV virus. It was developed by a team of Spanish
Spain
Spain , officially the Kingdom of Spain languages]] under the European Charter for Regional or Minority Languages. In each of these, Spain's official name is as follows:;;;;;;), is a country and member state of the European Union located in southwestern Europe on the Iberian Peninsula...
researchers at the Spanish National Research Council's Biotechnology National Centre headed by Dr. Mariano Esteban. The vaccine is based on the Modified vaccinia Ankara
Modified vaccinia Ankara
Vaccinia viruses re-engineered to express foreign genes are robust vectors for production of recombinant proteins, the most common being a vaccine delivery system for antigens. Concerns about the safety of the vaccinia virus have been addressed by the development of vectors based on attenuated...
(MVA) virus used during the 1970s to help eradicate the smallpox virus. The B in the name "refers to HIV-B, the most common HIV subtype in Europe". It has been stated by Dr. Esteban that, in the future, the vaccine could potentially reduce the virulence
Virulence
Virulence is by MeSH definition the degree of pathogenicity within a group or species of parasites as indicated by case fatality rates and/or the ability of the organism to invade the tissues of the host. The pathogenicity of an organism - its ability to cause disease - is determined by its...
of HIV to a "minor chronic infection akin to herpes".
Non-human testing
The vaccine was originally tested on a number of mice and macaque monkeysMacaque
The macaques constitute a genus of Old World monkeys of the subfamily Cercopithecinae. - Description :Aside from humans , the macaques are the most widespread primate genus, ranging from Japan to Afghanistan and, in the case of the barbary macaque, to North Africa...
in 2008 against the Simian immunodeficiency virus
Simian immunodeficiency virus
Simian immunodeficiency virus , also known as African Green Monkey virus and also as Monkey AIDS is a retrovirus able to infect at least 33 species of African primates...
(SIV) and it was found to be successful in every case in creating an immune system response to SIV infection.
Phase I testing
The initial testing on human subjects was conducted on a testing pool of thirty HIV-free individuals. Six of the pool were given a placeboPlacebo
A placebo is a simulated or otherwise medically ineffectual treatment for a disease or other medical condition intended to deceive the recipient...
and had no results. Of the other twenty-four individuals, twenty-two exhibited a "very strong immunological response against the HIV virus", bringing the success rate of the testing to 92%. The immune reaction that the successful testers exhibited lasted for a period close to a year for 85% of the testers, who had no "significant secondary effects". It was also shown that, from blood tests in the 48th week after administration of the vaccine, in 72.5% of the volunteers, "specific antibodies" had formed to combat possible HIV infection. Specifically, the blood tests revealed that the immune system production of CD4+ T lymphocytes and CD8+ T lymphocytes
Cytotoxic T cell
A cytotoxic T cell belongs to a sub-group of T lymphocytes that are capable of inducing the death of infected somatic or tumor cells; they kill cells that are infected with viruses , or are otherwise damaged or...
were at 38.5% and 69.2% each for the testers given the vaccine, while the amounts in the group given the placebo remained at 0%.
The next step with the vaccine within Phase I testing is to conduct a trial with HIV-positive testers, in order to determine if there is a "therapeutical effect of the vaccine" on those already infected with the virus.
Virology
In order to create the vaccine, researchers took the prior Modified Vaccinia Ankara virus and added four genesGênes
Gênes is the name of a département of the First French Empire in present Italy, named after the city of Genoa. It was formed in 1805, when Napoleon Bonaparte occupied the Republic of Genoa. Its capital was Genoa, and it was divided in the arrondissements of Genoa, Bobbio, Novi Ligure, Tortona and...
from the HIV genome, specifically those titled Gag
Group-specific antigen
Group-specific antigen is the genetic material that codes for the core structural proteins of a retrovirus.It comprises part of the gag-onc fusion protein.-Gag in HIV:...
, Pol
Pol (HIV)
Pol refers to a gene in retroviruses, or the protein produced by that gene.Products of pol include:-Reverse transcriptase:Common to all retroviruses, this enzyme transcribes the viral RNA into double-stranded DNA.-Integrase:...
, Nef
Nef (protein)
Nef is a protein expressed by primate lentiviruses. These include human immunodeficiency viruses and simian immunodeficiency virus . Nef is one of many pathogen-expressed proteins, known as virulence factors, which function to manipulate the host's cellular machinery and thus allow infection,...
and Env
Env (gene)
-Env in HIV:The env gene does not actually code for gp120 and gp41, but for a precursor to both, gp160. During HIV reproduction, the host cell's own enzymes cleave gp160 into gp120 and gp41. The host cell protease that cleaves Env into gp120 and gp41 is Furin...
.