Periodic Reporting for period 2 - VIVA (Vaccine development against variable pathogens)
Okres sprawozdawczy: 2021-08-01 do 2023-01-31
Antibodies are the correlate of protection for most existing vaccines. High affinity antibodies are generated by the diversification of selected naïve B cells in so called germinal centers (GCs). GCs are structures in the secondary lymphoid organs where B cells multiply by fast divisions and diversify through the incorporation of somatic hypermutations in the genes corresponding to the B cell receptor. For highly genetically variable viruses such as HIV-1, influenza A virus and SARS-CoV-2, only antibodies specific to conserved epitopes of viral proteins will lead to potent long-term protection. In addition, for HIV-1, potent neutralization of the virus is only achieved if unusually high levels of antibody somatic hypermutations are acquired through extensive germinal center reactions. Highly mutated and broadly neutralizing antibodies against HIV-1 develop during infection in some individuals but have never been successfully activated in individuals by vaccination. The requirement for a vaccine to be protective against HIV-1 is to first activate the appropriate naïve precursor B cells that bind conserved epitopes of the surface viral antigen, and second to stimulate these B cells to enter germinal centers and acquire high levels of B cell receptor somatic hypermutations. The overall objective of VIVA is to study the process of specific naïve B cell activation in the presence of competing polyclonal B cells, and the regulation of B cell recruitment to germinal centers. Understanding these processes in greater detail will help generating a vaccine against HIV-1.
In the beginning of the grant period, which was significantly hampered by the Covid-19 pandemic, we focused on setting up the infrastructure and acquiring all laboratory equipment needed to meet the scientific goals of the VIVA project. Personnel were recruited and contacts with relevant core facilities were initiated and developed. Genetic mouse models were acquired and rederived and relevant breeding was initiated. Protocols for working with mouse models were optimized and refined. Specifically, we optimized mouse models for HIV-1 antibody knock-in adoptive cell transfer as well as the generation of appropriate mixed bone marrow chimera models. In addition, we optimized protocols for the detailed definition of specific B cell populations by multi-color flow cytometry. Material transfer agreements and protocols for HIV-1 protein production were set up and optimized for use as immunogens. In summary we have established a solid environment with preliminary scientific data showing that our infrastructure and tools meet the needs to answer the proposed questions of the VIVA project.
The VIVA project is using novel mouse models and complex viral and non-viral derived antigens to advance our knowledge regarding the activation and regulation of epitope-specific precursor B cells in the context of competing polyclonal B cells. Apart from an increased understanding of basic B cell immunology, we expect future results from the VIVA project to inform the design of novel and optimized vaccines needed to protect against genetically variable viruses, including HIV-1.