04-20-2013, 03:28 AM
(This post was last modified: 04-20-2013, 05:54 AM by Administrator.)
Currently, the Centers for Disease Control and Prevention (CDC) recommend that all Americans above the age of six months receive an annual flu vaccine. This is important, because the predominant strain of influenza virus in the population can change from year to year. Influenza virus has a genome composed of RNA. Because RNA polymerase is highly error prone, the virus is prone to mutations. These mutations can change the proteins expressed on the surface of the virus. This process is called genetic drift. Therefore, even if the predominant strain remains the same for more than one year, the virus can still accumulate enough mutations that would make it difficult for the adaptive immune system to recognize. Scientists have been interested in developing a universal influenza vaccine, which could develop broadly neutralizing antibodies capable of recognizing proteins on many strains of the virus. This would require finding commonalities between different strains, so that antibodies would be able to recognize multiple strains. Development of a universal vaccine against multiple strains of influenza would be important for public health. Fewer vaccinations would need to be given to protect the population, resulting in improved compliance. Compliance among individuals able to receive the vaccine is important in providing herd immunity, which can help protect individuals who are not able to receive the vaccine. In addition, a universal influenza vaccine might also protect against newly emerging strains of influenza, thus reducing the likelihood of a worldwide pandemic.
The two major proteins on the surface of the influenza virus that are recognized by the immune system are hemagglutinin (H) and neuraminidase (N). The specific strain of influenza virus is indicated by the H and N molecules expressed on the surface of the virus; for example, H1N1 influenza has hemagglutinin type 1 and neuraminidase type 1 on its surface. Each year, scientists determine which strains of influenza will predominate, and use those strains to develop a vaccine. The virus is grown in hen eggs, and the proteins are isolated from the virus for use in the vaccine. As mentioned above, even if the primary circulating strain is H1N1 multiple years in a row, annual vaccination is recommended due to the virus’s ability to mutate. Many people are hesitant to be vaccinated annually, which may result in increased transmission of the virus, causing more damage during flu season.
Recently, Inovio Pharmaceuticals announced positive results from a trial of a universal H1N1 influenza virus vaccine. Unlike traditional seasonal influenza vaccines, the universal influenza vaccine was not designed to target a specific strain of influenza. Rather, it has been designed to recognize a broad range of H1N1 influenza strains. Scientists have been unsure whether this approach would result in an effective vaccination, due to the high mutability of influenza virus, and the difficulty in generating broadly neutralizing antibodies that would recognize multiple strains of virus.
The vaccine was able to induce antibody responses at a level comparable to that of the current seasonal vaccine against the current predominant influenza strain. Sixty percent of the volunteers who received the highest dose of the universal influenza vaccine were able to seroconvert, meaning they had developed protective levels of antibody against the current circulating influenza strain. This was similar to the percent of volunteers who received the seasonal vaccine. Importantly, the adverse effects noted during the study only including minor irritation at the injection site, demonstrating the safety of the universal influenza vaccine as well.
In addition to developing protective levels of antibody against the current influenza strain, many of the volunteers that received the universal influenza vaccine developed antibody responses against a variety of other H1N1 influenza viruses. This included the strain that caused the 1918 influenza pandemic, as well as many of the H1N1 strains that have been included in seasonal vaccines since 1986. The volunteers that received the universal influenza vaccine developed much more potent antibody responses against all these strains, and were more likely to seroconvert, than volunteers who received the current seasonal influenza vaccine. This helps demonstrate the broad cross reactivity of the immune response induced by the Inovio universal H1N1 influenza vaccine. Inovio is obviously very excited about the broad cross reactivity, and states that the information gained from this trial will also be useful in developing other universal vaccines and determining proper dosing.
References:
http://finance.yahoo.com/news/inovio-pha...00189.html
The two major proteins on the surface of the influenza virus that are recognized by the immune system are hemagglutinin (H) and neuraminidase (N). The specific strain of influenza virus is indicated by the H and N molecules expressed on the surface of the virus; for example, H1N1 influenza has hemagglutinin type 1 and neuraminidase type 1 on its surface. Each year, scientists determine which strains of influenza will predominate, and use those strains to develop a vaccine. The virus is grown in hen eggs, and the proteins are isolated from the virus for use in the vaccine. As mentioned above, even if the primary circulating strain is H1N1 multiple years in a row, annual vaccination is recommended due to the virus’s ability to mutate. Many people are hesitant to be vaccinated annually, which may result in increased transmission of the virus, causing more damage during flu season.
Recently, Inovio Pharmaceuticals announced positive results from a trial of a universal H1N1 influenza virus vaccine. Unlike traditional seasonal influenza vaccines, the universal influenza vaccine was not designed to target a specific strain of influenza. Rather, it has been designed to recognize a broad range of H1N1 influenza strains. Scientists have been unsure whether this approach would result in an effective vaccination, due to the high mutability of influenza virus, and the difficulty in generating broadly neutralizing antibodies that would recognize multiple strains of virus.
The vaccine was able to induce antibody responses at a level comparable to that of the current seasonal vaccine against the current predominant influenza strain. Sixty percent of the volunteers who received the highest dose of the universal influenza vaccine were able to seroconvert, meaning they had developed protective levels of antibody against the current circulating influenza strain. This was similar to the percent of volunteers who received the seasonal vaccine. Importantly, the adverse effects noted during the study only including minor irritation at the injection site, demonstrating the safety of the universal influenza vaccine as well.
In addition to developing protective levels of antibody against the current influenza strain, many of the volunteers that received the universal influenza vaccine developed antibody responses against a variety of other H1N1 influenza viruses. This included the strain that caused the 1918 influenza pandemic, as well as many of the H1N1 strains that have been included in seasonal vaccines since 1986. The volunteers that received the universal influenza vaccine developed much more potent antibody responses against all these strains, and were more likely to seroconvert, than volunteers who received the current seasonal influenza vaccine. This helps demonstrate the broad cross reactivity of the immune response induced by the Inovio universal H1N1 influenza vaccine. Inovio is obviously very excited about the broad cross reactivity, and states that the information gained from this trial will also be useful in developing other universal vaccines and determining proper dosing.
References:
http://finance.yahoo.com/news/inovio-pha...00189.html
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