Can we deal with HIV - 1 infection and cancer through vaccines?

With the development of science and technology and the increase of vaccine development strategies, can we cope with HIV - 1 infection and cancer through vaccines? Most immunologists believe that an effective AIDS vaccine must induce the formation of specific memory CTLs. If this is the case, non infectious vaccines are useless for preventing HIV infection (they cannot induce memory CTLs). In theory, the attenuated AIDS strain can be used for the development of attenuated vaccine to induce the body to form memory CTLs. However, AIDS virus has a strong mutation rate, and attenuated HIV - 1 is likely to cause infection of vaccinators through reverse mutation. Therefore, the attenuated AIDS vaccine is not feasible and cannot be used for general population vaccination. In the last tweet, we mentioned the carrier vaccine, and explored its feasibility for AIDS vaccine in this part. Up to now, no AIDS vector vaccine can effectively prevent HIV - 1 infection.

Even if we can design a safe vaccine that can induce the production of HIV-1 specific CTLs, the high mutation rate of AIDS virus alone can make the virus escape easily. Generally, the AIDS virus released by an infected cell contains at least one mutation compared with its original virus. Therefore, what an infected person contains is not an AIDS virus, but an AIDS virus library. When the infected person infects others, the new infected person is not infected with an AIDS virus, but also infected with a virus library. Therefore, even if specific CTLs can effectively resist certain strains of AIDS virus, in real infection, such CTLs will have no effect on other mutant AIDS virus strains. It can be seen that the high mutation rate of AIDS virus is the number one problem hindering the development of AIDS virus.

Despite the difficult situation, immunologists have been committed to the development of AIDS vaccine. In recent years, the antibodies of some AIDS patients have been proved to neutralize a variety of HIV - 1 mutants. If a vaccine can enable healthy vaccinators to form this "extensive neutralizing antibody", can it protect humans from HIV - 1 (at least most strains) infection? However, experiments have shown that: "extensive neutralizing antibody" can only be formed after multiple somatic high-frequency mutations after HIV infection. Then, can there be a vaccine that can enable the body to produce "extensive neutralizing antibodies" without multiple high-frequency somatic mutations? However, then again, even if we have this "extensive neutralizing antibody", it is not enough, because CTLs are the fundamental method to resist HIV-1.

In fact, there are still many vaccines waiting for us to develop, such as malaria, which kills one million people every year, tuberculosis, which kills three million people every year, and herpes simplex virus, which infects one third of the world's population.

After talking about AIDS, let's talk about cancer. Have you heard that vaccines can prevent cancer? Yes, vaccines can be used to prevent certain types of cancer (at least cancer caused by virus infection), such as liver cancer caused by hepatitis B virus infection. The study found that chronic infection of hepatitis B virus can increase the risk of human liver cancer by 200 times, and about 20% of long-term hepatitis B virus carriers will eventually develop into liver cancer. Hepatitis B virus is one of the most infectious viruses. One drop of blood is enough to infect the recipient with hepatitis B virus. Fortunately, at present, there is a hepatitis B virus vaccine on the market, which will be provided to medical personnel, people who have close contact with blood products, blood product manufacturers and children. Hepatitis B vaccine is a subunit vaccine that can induce memory B cells and specific antibodies. Humoral immunity can effectively block virus infection and eventually eliminate the virus, thus preventing the occurrence of hepatitis B virus related liver cancer.

Infection with specific carcinogenic human papillomavirus (HPV) can increase the risk of cervical cancer. Through sexual transmission, the virus causes many female infections (cervical cancer has become the second largest cancer among women and causes 250000 deaths every year). Although there are more than ten kinds of HPV associated with cervical cancer, two of them exist in 70% of cervical cancer patients: HPV-16 and HPV-18. HPV vaccine is also a subunit vaccine, which is composed of protective capsid protein of HPV virus. It is 95% effective in preventing HPV-16 and HPV-18 infection. Some HPV vaccines will add HPV-6 and HPV-11 capsid proteins. HPV-6 and HPV-11 infection will not develop into cervical cancer, but will cause male and female infected people to suffer from condyloma acuminatum. Perhaps, the idea of this vaccine development is that men will not take the initiative to vaccinate HPV vaccine because of cervical cancer prevention. At least male friends can benefit directly by adding these two strains. At present, there are 2, 4 and 9 HPV vaccines on the market in China.

At the end of the article, let's talk about adjuvant, the great contributor of the vaccine! What is adjuvant? Adjuvants are substances that make vaccines more like pathogens. After vaccination, adjuvant ingredients will "tell" the immune system that this thing is foreign and dangerous. This danger warning is not a problem for attenuated vaccines. For non infectious vaccines, especially subunit vaccines, how to attract the "eyes" of the immune system and make them look "very dangerous" is the key to the effectiveness of vaccines. Aluminum hydroxide (alum) is a commonly used adjuvant. One of its uses is to provide danger signals to the body. Cervarix (human papillomavirus vaccine produced by GlaxoSmithKline) uses MPL (a modified bacterial lipopolysaccharide [LPS]) as vaccine adjuvant. Adjuvants can enhance vaccine efficacy and reduce vaccine dose.