Why is difficult to clear the hepatitis B virus

If you eat a candy, it will eventually break down in the liver, stored. If you eat a drug, it will be one-third of toxicity in the liver to be released. The liver is the metabolic center of the human body and largest "chemical." It is essential for human life-sustaining activities, the vital organs, but also the basis for our health.

Hepatitis B is hepatitis B, listing the current known A, B, C, D, E, F. G 7 kinds of viral hepatitis "crimes", in addition to the last century, 80 years rampant 1:00 outbreak of hepatitis A, hepatitis B finally its long-lasting endurance, tenacious refractory to capture the lead, so that the public "talk about the liver pale." Around the world currently has about 400 million hepatitis B virus carriers, but in fact, China alone more than 45%, that is, nearly 7 million people have been infected with hepatitis B virus. The vast majority of them rely on their own defense against the power of a successful invasion of the virus, while the immune system problems people have with the various states with a variety of viruses, "Hepatitis B term" contact together. Hepatitis B, has become a hazard to human health of global issues.

Everything from the virus began

Of hepatitis B virus (HBV) is a DNA virus, like a snake venom secreted by certain body parts will only work for specific, like hepatitis B virus, only the liver, "has developed a taste," it is addicted to the biological Liver DNA virus family (hepadnavividae) in a family. The members of this family of viruses found in mammals and birds also have found that their structures, gene sequences and replication strategies are very similar, but between them they do not cross each other. In addition to the specific organ specificity, their hosts also have "racial requirements", such as HBV and gorillas are the only susceptibility.

Hepatitis B virus (HBV) Schematic diagram of

A complete hepatitis B virus particles, also known as Dane particles, only 42 nm in diameter, about one millionth of an ordinary egg. Shell and the core of hepatitis B virus has two parts, that is apart from the vast majority of viruses have a beautiful "capsid", the hepatitis B virus, but also coupled with a sophisticated "jacket." This case is the so-called "jacket", which thickness 7-8 nm, from the lipid bilayer and protein composition of envelope. Lipid bilayer containing S antigen, pre-S1 and pre-S2 antigen, which together constitute the shell large, medium and small three proteins form, collectively referred to as hepatitis B surface antigen (HbsAg), which is commonly known as the Australian people's resistance. With regard to the origin of anti-Australia there is still a story that was first serum from the Australian Aboriginal people separated, when the thought of a local ethnic-specific genetic markers, so called "Australia antigen." Later learned that hepatitis B virus surface antigen. The so-called antigen actually cause the body resistance response elements, while the contrast, the body can recognize and resist the elements is the antibody of the antigen.

Dano stripped shell particles, exposing the core of hepatitis B virus particles. Core particle diameter of 28 nm, showing three-dimensional icosahedral symmetry, and its surface is a real virus capsid by the hepatitis B virus core antigen (HBcAg) component. Nucleocapsid free state only in the liver cell nuclei observed. Through strong detergent or enzyme treatment methods, but also revealed another major HBV antigens e antigen, its essence is not yet clear, but most people think is the core of the fragment.

Dano is the center of ring particles and there are gaps in the DNA double-stranded, and the dependent DNA polymerase in the above. Hepatitis B virus genome of one of the most striking feature is that it is very small, the DNA molecule contains about 3200 nucleotides of about more than the largest known genome of the virus hundreds of times smaller, and the human genome have compared only the one in a million. And the hepatitis B virus DNA, two chains of different lengths, long-chain integrity, and length of the constant negative chain. Short-chain is a positive chain of variable length, probably long-chain, 50% to 80%. Surface antigen and core antigen are encoded by the DNA from Dane particles.

Under the electron microscope to observe the hepatitis B virus, 3 different patterns: large spherical particles, small spherical particles and tubular particles.

In reality, the electron microscope to observe the hepatitis B virus, 3 different patterns: large spherical particles, small spherical particles and tubular particles. Large spherical particles is Dano particles. A small ball-shaped particles about 22 nm in diameter, is the hepatitis B virus infection in the blood up to see the kind. It consists of the composition of surface antigen and does not contain hepatitis B virus DNA and DNA polymerase. Tube-shaped particles, diameter about 22 nm, length 50 ~ 70 nm. Fact, by the coming together of several small spherical particles formed, but the same with the HBsAg antigenicity. Whether a small ball or a tube-shaped particles are not a complete hepatitis B virus particles, which are infected with hepatitis B virus in liver cells capsular synthesis of excess, free in the body's blood circulation.

DNA competition

Unlike a real organism, the virus does not pass through such means as reproductive growth and division itself, but as we like the casting machine parts, according to some copies of out of the mold. Virus DNA contains a number of procedures to guide the virus genetic material and other components of the proliferation of structural proteins. In addition, the viral DNA, also contains some information so that a single component to factor in the cell with the help of self-assembled into new virus particles.

In medicine, the propagation of the virus is called "Copy" in the replication process, there are two very important factors: one is the catalyst, the other is the template. Did not these two factors, hepatitis B virus can not be copied. Hepatitis B virus replication "catalyst" is the hepatitis B virus DNA polymerase. Without this the role of polymerase, hepatitis B virus replication will stop.

Hepatitis B virus genome (DNA) is a two helix DNA chains surrounded by a ring structure. One of the negative long-chain has been formed a complete ring; the other is a shorter length of chain, was semi-ring. After the infected liver cells, this semi-ring of the DNA chain will appear as a negative chain as a template, in the catalyst ─ ─ The role of hepatitis B virus DNA polymerase be extended eventually to form a complete ring. At this time of the hepatitis B virus genome to form a complete ring of double-stranded DNA. We call this covalently closed circular DNA called DNA (ie cccDNA), it can be seen as the original template of viral replication. After the formation of the template, the virus genome will be one of a cccDNA as a template, the use of liver cell gene in the DNA polymerase enzymes and a "catalyst", a gene has a gene copy to form a minus-strand and plus-strand. Finally re-assembled together to form a new hepatitis B virus DNA particles.

Of hepatitis B virus replication Effect Picture

This cccDNA is the hepatitis B virus replication an important intermediate product, once it is formed in the liver cell nucleus, it has a high degree of stability, persist in the liver cells, not only played just said, "template" role, but Also, as deeply rooted in the soil of the weed is difficult to completely remove the same. Antiviral drugs, no matter what, no matter how much the intracellular DNA were inhibited, and regardless of how long medication, are very difficult to remove this cccDNA. As long as the liver cells, only a few amount of cccDNA, when the withdrawal, the nucleus The cccDNA viral replication and can once again become a "model", to continue replicating hepatitis B virus DNA, which is very difficult to eradicate hepatitis B causes.

In real life, most people are familiar with the "two pairs of semi-Hepatitis B" In fact, detection of hepatitis B virus infection is not pathogenic substances and materials (in other words, not a live hepatitis B virus), so check the "two pairs of semi-Hepatitis B" only reflects whether a person is infected with hepatitis B, but can not directly reveal the depth of hepatitis B virus replication in the human body and disease situation, would be unable to better guide clinical use of drugs and the development of treatment programs. In order to find a correct and reasonable quantitative indicators of the virus, the experts after years of study, found an effective way to ─ ─ hepatitis B virus DNA quantitative test. This test can reflect the living blood of patients with the virus load contribute to understanding of hepatitis B virus in the patient's body around the world. Hepatitis B virus DNA that contain genetic information of the material, which is the basis for replication of hepatitis B virus progeny. Therefore, the understanding of hepatitis B virus DNA in the patient's body rise and fall of a situation, we indirectly ascertained the situation of hepatitis B virus replication.

Small knowledge: two pairs of semi-hepatitis B

By detecting antibodies to hepatitis B virus can easily determine whether the dyed his sense of hepatitis B virus, anti-detection of Australia is an important clinical diagnostic indicators. But the mere detection of an antibody to it has no hair out completely determine the current status of hepatitis B virus, the best solution is to remove and hepatitis B-related antigens and antibodies all detected, that is: hepatitis B surface antigen (HBsAg), e antigen (HBeAg) and core antigen (HBcAg), as well as the corresponding three kinds of antigens induced antibodies, respectively, the surface antibody (anti-HBs), e antibody (anti-HBe) and core antibody (anti-HBc). Due to technical reasons, general laboratory tests can not be the core antigen, so three pairs of antigen-antibody less one, so the hospital is testing HBV-check "HBV 5", commonly known as two pairs and a half.

Commonly called "HBeAg" refers to the hepatitis B surface antigen, e antigen, core antibody positive 3; and "Xiao Sanyang" refers to the surface antigen, e antibody, core antibody positive. The antigen-antibody in clinical practice there are different directions of their meaning: the surface antigen (HBsAg) expressed in vivo existence of hepatitis B virus; surface antibody (anti-HBs) said that whether there is a protective body that can resist viruses; е antigen (HBeAg) indicated that virus replication and infectious; е antibody (anti-HBe) indicated that viral replication is suppressed; and core antibody (anti-HBc) mainly indicate whether infected with hepatitis B virus.

In fact, hepatitis B virus itself does not cause the disease, its liver cell injury is mainly cleared by the body's immune system response caused. Hepatitis B virus infection after the body, invades the liver cells, resulting in liver cell changes in certain structures. To stimulate the body's own liver cells to produce immune response, thus resulting in cell damage would be. In more severe cases of liver damage, the body's immune system and even has not been violated HBV with liver cells to kill, it also shows that self-inflammation immune response in the pathogenesis of hepatitis B has an important significance. With normal immune function, body HBV-infected liver cells a series of immune responses, as has been the gradual elimination of the virus, and gradually recovered. This is what China has more than 45% of people had been infected with hepatitis B virus, but eventually the majority of hepatitis B virus, the human body has no residual causes.

While in the past few million years, gradually in the course of human evolution obtained from the virus, where hundreds of genes, but when a new virus invasion of the body when the normal work of a strong immune system, or can not tolerate the virus DNA to the cell invasion and occupation of the resources will not hesitate to cleansing "invaders."

In the virus is not over yet

Fast variation of viral replication fast, and close to the body's cells and may even be combined with the cell DNA, life-long accompanied by ordinary drugs against the virus is difficult to do no harm to the cells, which are treated virus considerable difficulties faced by . Until now, at home and abroad have not yet effective way to cure hepatitis.

Once their own immune system can not be blocking the invasion of the virus, then the grasp of the laws of the virus, antiviral treatment is still rule-based, from the characteristics of the virus start against the virus entry, and block the replication of the virus and prevent viral protein production, to contain the virus escape channels, and to avoid drug-resistant virus, and so many scientific studies have been started.

Better recognized internationally, the clinical application of the most successful and most widely used is the interferon treatment and nucleoside analogues lamivudine therapy, but these two treatments, there are strict conditions of application, and the medication for a long time completely cured the likelihood is low, there can be only achieved 大三阳 some people turn Xiao Sanyang, DNA negative in such a clear role of the virus within the blood, but also have certain side effects. Lamivudine may lead to virus mutation, so that lamivudine failure. These two drugs, then there may be inadvertent withdrawal intense rebound condition. So, scientists are actively seeking their sister drugs, some have entered Phase III clinical trials. 2004 Nian October 29 to November 2 in Boston meeting of the International Liver Diseases year will be more coverage of the anti-viral treatment of viral hepatitis were reported, a change the past, hepatitis is more boring situation, anti-viral treatment involving wide canopies. As the current anti-HBV drugs have limited efficacy, many scholars believe that the future development direction for the combination therapy, which is the focus of future research.

For the treatment of hepatitis B vaccine, China's Fudan University, Wen Yumei research group led by academician, Chongqing, Zhejiang University, Kai-chen companies as well as three teams have done a lot of work. Now also has entered the clinical validation phase.

In addition to therapeutic work, prevention of fact, for the whole community and individuals, and perhaps more should receive attention, whether on the basis of the establishment of preventive measures in health for the hepatitis B is currently the most effective way. China's universal vaccination against hepatitis B virus preventive vaccine has a very good preventive effect. Healthy people before and after vaccination, the body will produce the vast majority of hepatitis B virus protective antibodies, it will not be infected with HBV. Babies born to hepatitis B virus carriers, as long as the first day of injection of hepatitis B vaccine at birth, later gradually entrenched vaccination can generally prevent hepatitis B virus infection. Therefore, preventive hepatitis B vaccine has become a routine vaccination of newborn babies. China's newly developed out of a hepatitis B associated Miao, through clinical validation, can not only effectively enhance the immune response, has also injected a single branch of hepatitis A vaccine, hepatitis B vaccine the same effect, but also help to reduce the kinds of radio frequency and leakage rates. Previously, only the United States successfully A, hepatitis B vaccine with vaccination use. Its use will be further beneficial to a hepatitis B prevention and control work.

In the past 30 years, the discovery of the hepatitis virus, and research, as well as blood screening and vaccine use, so that scientists will soon be convinced of viral hepatitis under the control of humans, it will never be like the past thousands of years, as pairs of Association of human-induced wei