The discovery of an antibody capable of blocking the HIV virus raises medical expectations to generate better treatments against the consequences that the acquired insufficiency syndrome, AIDS, causes in patients sick with the virus.
Berlin, October 15 (DW).- 44 million deaths all over the world is the sad balance of Acquired immunodeficiency syndrome (HOW) since it was announced in 1981. He HOW It is considered one of the worst epidemics that the humanity has experienced until now, as a result of infection by human immunodeficiency virus (HIV). Although the number of deaths from infection with the HIV has continually decreased thanks to the preventionEven today people are still dying because of this disease. In 2024 were approximately 630 thousand people all over the world.
Therefore, the discovery of Cologne University Hospital raises hopes that another weapon has been found in the fight against AIDS.
More than 800 antibodies against HIV
The research team of Florian Klein, director of the Institute of Virology, examined blood samples from 32 people. They were all infected with HIV, but on their own, without treatment, they developed an especially strong and broad-spectrum antibody response against the virus.
The researchers tested more than 800 different antibodies from these blood samples in the laboratory to evaluate their ability to neutralize HIV. One of them, called 04_A06stood out among the others. This antibody blocks the site where the virus attaches to the body’s cells during an infection. That is, it prevents HIV from entering cells. Once inside the cell, the virus reprograms it for its own reproduction, thus weakening the immune system in the long term.
Broad HIV Antibody Neutralizes 98.5% of Strains
Antibody discovered that blocks almost all known HIV variants in neutralization assays.
The newly identified antibody 04_A06 proved to be particularly effective in laboratory tests. It was able to neutralize 98.5 percent of more… pic.twitter.com/SHu2ENIOeC
— Professor Erwin Loh (@erwinloh) October 8, 2025
The blueprint for antibodies is found in the human immune system, in the so-called B lymphocytes. When these encounter pathogens, they mature into plasma cells that release large quantities of antibodies, including 04_A06. The researchers deciphered the blueprint of this antibody and reproduced it.
“It is not necessary to draw blood from patients again and again, but instead you introduce this blueprint into another cell and tell it: please produce this protein, that is, this antibody,” the team said.
Antibody 04_A06: for HIV therapy and prophylaxis
The antibody 04_A06 managed to completely neutralize most viruses in mice containing components of the human immune system and infected with HIV. In total, the researchers conducted experiments with nearly 340 HIV variants, including some that were already resistant to other antibodies.
“The viruses are quite different, and that makes AIDS so difficult to treat, because there is great genetic diversity among viruses,” explains project director Florian Klein. However, the newly discovered antibody managed to neutralize 98 percent of the HIV variants tested.
Huge HIV update.
Researchers in Cologne found a single antibody; 04_A06; that neutralized 98.5% of more than 300 HIV variants in lab tests. In humanized mice, one dose pushed the virus below detection and kept it there. It works by locking onto a part of the virus that hardly… pic.twitter.com/VfkUBil8oE
— Dustin (@r0ck3t23) October 9, 2025
Therefore, the 04_A06 It could help people who are already infected with HIV, since it blocks the virus’s access to the cell. “It attaches to the virus receptor, and then the virus is blocked and can no longer infect the target cell.” Furthermore, viruses with antibodies attached would be better recognized and actively eliminated by the human body’s immune system, explains Klein.
He 04_A06 It could also have a preventive effect to avoid HIV infections. “Then the antibody would already be present, and if a virus enters the body, it would be intercepted before it can infect a cell,” Klein says.
Until now there is no vaccine against HIV
The newly discovered antibody could act as a so-called passive immunization. An active immunization would be a vaccine that allows the body to produce its own antibodies. But that doesn’t exist yet.
Various medications in the form of tablets or injections are currently used as a prophylactic measure against HIV infections, and with considerable success. However, the tablets must be taken, in most cases, daily. Long-acting preparations with a depot effect, such as those containing the active ingredient Lenacapavirhave already been approved in the European Union after their authorization in the United States, but are not yet available for purchase in the EU.
The idea behind prophylaxis with antibodies like 04_A06According to Florian Klein, it would be “to do without the tablets, since there would be a greater than 90 percent probability of avoiding an infection.” Antibody prophylaxis would have to be administered approximately every six months.
The 04_A06 antibody was found to neutralize 98.5% of HIV-1 isolates across different clades and panels, making it one of the most broadly active antibodies identified.
— Frank Paul Mora (@InTime_49) October 6, 2025
A long road ahead
There is still time for the 04_A06 becomes an AIDS drug, believes Christoph Spinner, head of infectious disease at the Rechts der Isar Hospital of the Technical University of Munich (TUM). Because the Cologne study is based solely on laboratory data, “so the effectiveness cannot be directly translated into real life.” More studies on the dosage, tolerance and effectiveness of the antibody must now follow.
Other broadly neutralizing antibodies against HIV have already been discovered, but “the 04_A06 “It is definitely an extraordinarily potent representative of this group,” said Alexandra Trkola, director of the Institute of Medical Virology at the University of Zurich. “It cannot yet be predicted whether the antibody will prove effective in clinical use,” says Trkola, “but the signs are, in any case, very promising.”