HIV백신 반복 접종 부작용, HIV백신 반복 접종, HIV백신,side effects of repeated HIV vaccination, repeated HIV vaccination, HIV vaccine

 

 

 

HIV 백신을 반복 접종하면 바이러스를 막아야 할 항체들이 오히려 서로를 공격하며 백신 효과를 떨어뜨릴 수 있다는 연구 결과가 나왔다. 신종 코로나바이러스 감염증(코로나19)이나 독감 백신과 같이 반복 접종이 요구되는 백신의 설계에도 시사점을 줄 수 있는 중요한 발견이다.

미국 스크립스 연구소와 스위스 로잔연방공과대(EPFL)를 포함한 국제 연구진이 인간 면역결핍 바이러스(HIV) 백신을 여러 번 맞을 때 면역 체계가 예상치 못한 방식으로 작동해 백신 효과를 낮출 수 있다는 사실을 밝혀 냈다. 연구 결과는 국제 학술지 ‘사이언스 면역학(Science Immunology)’에 게재됐다.


HIV 바이러스는 사람의 면역 체계를 공격해 면역력을 떨어뜨리는 바이러스다. HIV 감염으로 인체의 면역력이 상당히 저하되면 감염증이나 종양이 나타나기 시작하는데, 이를 후천성면역결핍증후군(AIDS·에이즈)라고 한다.

현재 HIV에 대한 백신이 있지만 한 번 접종만으로는 충분한 면역 반응을 유도하기 어렵다. HIV 바이러스는 몸속에서 다양한 형태로 변이하며 면역 체계의 공격을 피하기 때문이다. 따라서 반복 접종을 통해 면역 체계가 다양한 형태의 HIV를 인식하고 대응할 수 있도록 해야 한다. 또 HIV 바이러스는 겉껍질(외피 단백질)을 가지고 있어 몸의 면역 체계가 쉽게 공격하지 못하지만, 반복 접종은 바이러스의 약점을 찾아 공격하는 강력한 항체를 만들고 면역 체계가 바이러스를 기억하도록 돕는다. 지난해 미국의 제약회사 길리어드 사이언스가 개발한 HIV 백신 ‘레나카파비르’는 연 2회 접종하면 감염 위험을 약 96% 낮춰준다.

연구진은 HIV 백신의 반복 접종이 면역 반응에 미치는 영향을 조사하기 위해 토끼와 붉은털원숭이를 대상으로 실험을 진행했다. HIV 백신을 반복 접종한 뒤 생긴 항체들을 관찰한 결과, 원래는 HIV 바이러스를 공격하기 위해 만들어진 항체(1차 항체, 항 HIV 항체)가 다른 항체들의 공격 대상이 되는 걸 발견했다.

항 HIV 항체를 공격하는 항체는 ‘항 면역복합체 항체’라고 한다. 항 면역복합체 항체는 단순히 항 HIV 항체를 공격하는 것에 그치지 않고 항원과 항체 복합체와 결합해 면역 반응을 복잡하게 만들었다. 특히 바이러스를 공격해야 할 자리를 차지해 버려 면역 체계가 바이러스에 충분히 대응하지 못하도록 만들었다.

연구진은 항 면역복합체 항체가 만들어지는 과정을 다음과 같이 설명했다. 먼저 백신 접종으로 HIV를 공격하는 항체가 생긴 뒤, 이 항체가 바이러스의 주요 부위를 완전히 덮어버리면 몸이 바이러스 대신 항 HIV 항체를 새로운 적으로 인식한다. 그러면 이 항체를 공격하는 또 다른 항체인 항 면역복합체 항체가 생긴다. 반복적으로 HIV 백신을 맞을 경우 항 면역복합체 항체의 생성이 여러 번 일어나면서 면역 체계가 비효율적으로 변하고, 결국에는 바이러스를 막는 효과를 약하게 만들 수 있다.


연구진은 “원숭이 실험에서 이러한 항체 반응이 확인된 만큼, 인간이 HIV 백신을 여러 번 맞을 때도 비슷한 면역 반응이 나타날 수 있다”며 “HIV 백신뿐 아니라 여러 번 접종이 필요한 다른 백신에서도 비슷한 문제가 생길 수 있다”고 강조했다. 그러면서 “백신의 효과를 높이기 위해선 백신 설계 단계에서 면역 반응의 복잡성을 더 깊이 이해하는 것이 중요하다”며 “반복 접종이 면역 반응을 비효율적으로 만들지 않도록 항원 설계를 개선하거나, 항체 간 불필요한 상호작용을 차단하는 기술이 필요하다”고 덧붙였다.

 

 

 

 

Repeated vaccination of HIV can cause antibodies to block the virus to attack each other and reduce the effectiveness of the vaccine, according to a study. It is an important discovery that can give implications for the design of vaccines that require repeated vaccinations, such as COVID-19 or flu vaccines.

International researchers including Scripps Research Institute in the U.S. and the Federal Institute of Technology in Lausanne, Switzerland, have found that multiple doses of the human immunodeficiency virus (HIV) vaccine can cause the immune system to function in an unexpected way and reduce the effectiveness of the vaccine. The results of the study were published in the international journal Science Immunology.


HIV is a virus that attacks a person's immune system and lowers immunity. When a person's immune system is significantly reduced due to HIV infection, infections or tumors begin to appear, which is called acquired immunodeficiency syndrome (AIDS).

Currently, there is a vaccine against HIV, but it is difficult to induce a sufficient immune response with just one dose. This is because HIV mutates into various forms in the body and avoids attacks by the immune system. Therefore, it is necessary to enable the immune system to recognize and respond to various forms of HIV through repeated vaccination. In addition, HIV has an outer shell (outer skin protein) that makes it difficult for the body's immune system to attack, but repeated vaccinations create powerful antibodies that find weaknesses and help the immune system remember the virus. Last year, the HIV vaccine "Renacapavir," developed by Gilead Sciences, an American pharmaceutical company, reduces the risk of infection by about 96 percent when administered twice a year.

The researchers conducted experiments on rabbits and rhesus monkeys to investigate the effects of repeated vaccinations of HIV on immune responses. After observing antibodies that were created after repeated vaccinations, they found that antibodies (primary antibodies, anti-HIV antibodies) originally made to attack HIV viruses were targeted by other antibodies.

Antibodies that attack anti-HIV antibodies are called 'anti-immune complex antibodies'. Anti-immune complex antibodies do not just attack anti-HIV antibodies, but combine with antigen and antibody complexes to complicate the immune response. In particular, it has occupied a place to attack viruses, making the immune system unable to adequately respond to them.

The researchers explained the process by which anti-immune complex antibodies are made as follows. First, the body recognizes anti-HIV antibodies as a new enemy instead of the virus when the antibody completely covers the main part of the virus after vaccination. Then, another antibody that attacks this antibody, an anti-immune complex antibody, is produced. Repeated HIV vaccination can cause multiple productions of anti-immune complex antibodies, resulting in the immune system becoming inefficient and ultimately weakening the effect of stopping the virus.


"As these antibody responses have been confirmed in monkey experiments, similar immune responses can occur when humans are vaccinated against HIV multiple times," the researchers said. "Similar problems can occur not only in HIV vaccines but also in other vaccines that require multiple vaccinations." "In order to increase the effectiveness of the vaccine, it is important to understand the complexity of the immune response in the vaccine design stage," he added. "We need technology to improve antigen design or block unnecessary interactions between antibodies so that repeated vaccination does not make the immune response inefficient."