June 26, 2022

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mRNA HIV vaccine animal experiment by Fauci team: Safe and Efficient

mRNA HIV vaccine animal experiment by Fauci team: Safe and efficient



 

mRNA HIV vaccine animal experiment by Fauci team: Safe and efficient. 

Nature Medicine: Experimental mRNA HIV vaccine animal experiment by Fauci team shows safety and efficiency.

In a new study published in Nature Medicine on December 10,  a research team from the National Institute of Allergy and Infectious Diseases (NIAID) under the National Institutes of Health (NIH) showed that a research based on The mRNA experimental HIV vaccine has shown safety and effectiveness in mice and non-human primates.

The vaccine can trigger the antibody and cellular immune responses required against HIV-like viruses.

Compared with non-vaccinated animals, the risk of exposure to human immunodeficiency chimeric virus (SHIV) infecting apes in rhesus monkeys that received the initial immunization and multiple booster immunizations was reduced by 79%.

 

mRNA HIV vaccine animal experiment by Fauci team: Safe and efficient

 

Dr. Anthony S. Fauci, the co-leader of the study and the director of NIAID, said: “Although the global scientific community has worked hard for nearly 40 years, a vaccine that effectively prevents HIV is still an elusive goal.

This experimental nature The mRNA vaccine combines several features and can overcome the shortcomings of other experimental HIV vaccines, so it is a very promising method.”

The working principle of the experimental vaccine is similar to that of the mRNA COVID-19 vaccine.

However, the vaccine does not carry the mRNA instructions for the spike protein of the new coronavirus, but instead provides encoding instructions for the production of two key HIV proteins, Env and Gag .

The muscle cells of the vaccinated animals assemble these two proteins to produce virus-like particles (VLPs) with large numbers of Env copies scattered on the surface.

Although they do not cause infection due to lack of HIV’s complete genetic code, these VLPs match the infectious intact HIV in terms of stimulating an appropriate immune response.

mRNA HIV vaccine animal experiment by Fauci team: Safe and efficient

 

Researchers report that in the study of mice, two injections of VLP-forming mRNA vaccine can induce the production of neutralizing antibodies in all animals .

The Env protein produced in mice according to mRNA instructions is very similar to the protein produced in the entire virus, which is an improvement on the previous experimental HIV vaccine.

The co-corresponding author of the study, Dr. Paolo Lusso, said: “Displaying multiple true copies of HIV envelope protein on each VLP is a special function of our platform. It closely mimics natural infections and may play a role in triggering the expected immune response. It worked.”

The team then tested the Env-Gag VLP mRNA vaccine in rhesus monkeys.

The details of the vaccination protocol vary between the subgroups of animals vaccinated, but all involve priming the immune system with a vaccine that has been modified to optimize antibody production.

After the start of the first phase, several intensive vaccinations were carried out within one year.

In addition to the genes used in the initial vaccine, the booster vaccine also contains Gag mRNA and Env mRNA from two branches of HIV evolution .

Researchers use multiple virus variants to preferentially activate antibodies to combat the more conserved “shared” regions (targets of broadly neutralizing antibodies) in Env, rather than the more different variable regions in each virus strain.

The researchers said that although the delivered mRNA dose was high, the vaccine was well tolerated, and only mild and temporary adverse reactions, such as loss of appetite, occurred in rhesus monkeys.

By week 58, all vaccinated macaques had produced measurable levels of neutralizing antibodies against most strains in a test panel of 12 different HIV strains.

In addition to neutralizing antibodies, the VLP mRNA vaccine also induced a strong helper T cell response.

 

mRNA HIV vaccine animal experiment by Fauci team: Safe and efficient

Starting from the 60th week, the immunized and non-immunized control group of rhesus monkeys were exposed to SIV through the rectal mucosa every week.

Since non-human primates are not susceptible to HIV-1 infection, scientists used chimeric SHIV in an experimental environment, which can replicate in rhesus monkeys.

After 13 weeks of vaccination, 2 of the 7 immunized rhesus monkeys were uninfected.

The infection of other immunized animals was delayed overall, and the infection occurred in an average of eight weeks. In contrast, unimmunized animals are infected after an average of three weeks.

Lusso said: “We are now improving the vaccine program to increase the quality and quantity of VLPs produced.

This may further increase the effectiveness of the vaccine, thereby reducing the dose of the initial immunization and booster required to produce a strong immune response.

If it is proven Safe and effective, we plan to carry out a phase one trial of the vaccine platform in healthy adult volunteers.”

 

 

Link to the paper:

https://www.nature.com/articles/s41591-021-01574-5

mRNA HIV vaccine animal experiment by Fauci team: Safe and efficient

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