Are there universal H1N1 vaccine?
Posted on October 14, 2009
Filed Under H1N1 Prevention | Leave a Comment
Traditional influenza epidemic season is coming, all over the outbreak of a stream infection events. Although a vaccine against the H1N1 Influenza A have been successfully developed and put into production, but why the influenza vaccine can not be like a vaccination, long-term effective? Currently, scientists are manufactured through the soft underbelly of universal influenza virus vaccine – it can withstand test?
Since 1948, the World Health Organization Global Influenza Surveillance Network has been established, scientists in related fields each year to the national Center for Disease Control and reference laboratories reported from pandemic influenza and the strain of the virus real-time situation analysis and summary. Through analysis of these data, they will come out and is likely to predict epidemic of influenza type of vaccine manufacturers in order to plan ahead, research and development and reserves a targeted vaccine.
According to the British “Guardian” reported that the British government to promote a flow of medical and nursing staff the first injection of vaccine to achieve protection purposes, the survey showed that more than 30% of the nurses rejected the proposal on the grounds that a flow of vaccine produced urgently in order to rush, once hit variation, have to try again.
Why can not flu vaccine has a glorious history like other counterparts, be able to do a vaccination, long-term effective?
Changing
This topic is also necessary to talk about the characteristics of influenza virus itself. And most of the viruses, influenza virus is from the core of genetic material, peripheral and the most outer protein shell of the capsule formed. In addition, the protruding capsule along with two very important glycoproteins – hemagglutinin (H) and neuraminidase (N). Is on the basis of different subtypes of the virus hemagglutinin and neuraminidase of the different division.
Hemagglutinin and neuraminidase sub-types, as well as, not only in virus infections play an important role, owing to its strong antigenicity, they often become the design of flu vaccines used in targets. The so-called antigen refers to stimulate the body’s immune system to produce immune responses. Once the harassment of human influenza virus, therefore, just as swaggering, barely veiled group of thieves broke into the region of martial law, will immediately cause the immune system’s attention.
Although the influenza virus so high-profile, but it still has its own survival, and one unique skills is the rapid mutation. The above-mentioned two kinds of proteins, for example, they are almost able to do a few years a small change (antigenic drift), 10 years, a drastic change (antigenic shift).
This makes the immune system while a new virus capable of timely response, but many times to organize an effective counterattack in the body, before the virus has shown a trend of full-scale invasion. Meanwhile, the older of the influenza vaccine is like the old revolutionary has encountered new problems, almost completely lost the ability to accurately anti-virus. Therefore, in order to prevent influenza, people were forced every year to finish the long march a needle.
A hit
Given the current prevalence of influenza and influenza vaccine in short-board, with many scientists are hoping to find the Achilles heel of influenza viruses, and use it as stepping stone, developed with broad-spectrum nature can deal with all influenza viruses, vaccine .
The first step of this journey is to find a suitable target, the current research has achieved a breakthrough. Influenza viruses are indeed some variation is not frequent conservative proteins, such as the M2 protein is one of them. Electron microscope at the virus’s envelope protein can vaguely see this on the head. Studies have shown that influenza virus was found eating since the frequency of mutations in this protein has been very low.
In addition to conservative, the antigenic target is a measure of the strength of another important indicator of good or bad. As the M2 protein in influenza virus surface were very low, in this respect, one would not subsequently had. Compared with neuraminidase and hemagglutinin of Thieves image of it as “quietly enters the village, fire a gun’s not” the thief. It is difficult to conduct a comprehensive mobilization to stimulate the immune system is rapidly creating a large number of antibodies against the virus.
However, immunological stage of development, scientists there are many ways to overcome this obstacle. Example, the U.S. researchers Walter fils means of the use of genetic engineering will be M2 protein gene extracellular domain (M2e) with a known HBc hepatitis B virus genes linked together, and then the fusion gene into the large intestine bacilli in vivo, after cultivation of E. coli produced a lot of M2e-HBc fusion protein. The test mice experiments have shown that some of the fusion protein can induce mice to produce antibodies against the M2e protein. In the last year, completed Phase I clinical trial among 78 subjects in about 90% of the subjects also successfully produced antibodies.
All roads lead to Rome, the United Kingdom Buckinghamshire PepTcell’s vaccine expert Stuart Dr. Luo Binxun another way, abandoning the traditional and in response to antigen-antibody approach to restraint the virus. Although he is still aiming to target M2 protein, but the use of it is the role of cell-mediated immunity, through a kind of cytotoxic T cells, through its role to deal with anti-virus.
Achilles heel is only a weakness, but in the eyes of scientists, influenza virus may have more of the Gate of Life awaiting exhumation. Not long ago, the United States and France co-researchers in the “Nature Structural and Molecular Biology,” published in the journal article said that they haemagglutinin structures found in the stem parts of the amino acid sequence and structure of a fairly conservative target. Similarly, the body’s immune system is still unable to detect antigen in the region, but the existing technical means it is entirely possible in vitro to produce antibodies against them, and this conservative presence also ensures that production of the “ammunition” long-term effective.
One of the authors of this article, Sui Jianhua US-based Chinese scientists said they are in the laboratory of the hundreds of millions of monoclonal antibodies to several rounds of scanning, monoclonal antibodies can finally get in and a half of the existing influenza viruses, including H5N1 highly pathogenic avian influenza and the 1918 Spanish flu H1N1.
In addition, many researchers will be looking for sights of the virus within the protein, in a few years ago, pharmaceutical companies developed a vaccine based on influenza virus nucleoprotein with a view to play a broad-spectrum anti – effects of the virus, but unfortunately, because we have immunity against influenza virus itself and yet in-depth understanding of the mechanism, this vaccine does not play a protective effect was expected.
Really universal?
Universal vaccine’s name gave rise to an infinite beautiful reverie, but the vaccine can really play a full role in disease prevention, but also solid clinical trial data do the talking. Although theory point of view, as long as the vaccine designed to target the virus to evade the body off the site of a high mutation rate, get the vaccine should have a “universal” effect.
Mentioned above, the most promising M2e vaccine, its universal nature of many scientists questioned. Although the greatest threat is to bring people to influenza, but influenza B is still not to be underestimated, it is sometimes caused by a regional epidemic, while the latter is precisely the M2e vaccine is powerless.
In addition many researchers believe that human influenza viruses as a long-term coexistence of the virus, its “smart” level far more than people’s imagination. The conservative mutation of those who have not yet part of the reason may be because they have not accepted the selection pressure test.
As large-scale use of antibiotics has led to frequent drug-resistant strains of the same in order to M2 protein or other conservative parts of the target of the vaccine or monoclonal antibody drugs to put it into practical, it is possible to create a specific selection pressure, allows those with resistant strains are becoming prominent. This situation is much more rapid mutation rate of AIDS in the research process once there were precedents.
Infectious disease expert, professor at the University of East London, Long Cutler, referring to M2e vaccines, not without a warning means that land, said: “This vaccine, once large-scale promotion, it is possible to promote the beginning of influenza virus M2 gene mutation. If this is the case , then the universal vaccine was frequently updated, the effect of the Jiugen traditional vaccines are not very different. ”
Many of today’s universal vaccine is still in pre-clinical or Phase I clinical trials, according to the United States Institute of the virus, the WHO experts彼得帕莱斯mentioned the concept of universal vaccination has been surfaced for decades, However, according to his estimate, the true sense can be against all strains of influenza virus vaccines will probably take 5 to 10 years to appear. Today’s seasonal vaccine to healthy adult infection rate reduced by 70% to 90%, even for the emerging virus, and sometimes also have some protective effect, so how to make good use of existing weapons, to better address the immediate outbreak is the key.
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