Booster vaccination strengthens existing defenses against newer COVID-19 variants
The SARS-CoV-2 genome is subject to constant mutations. Some of these mutations reduce the effectiveness of RNA-based vaccines, which consequently have to be adapted regularly. Until now, however, it was unclear how the immune system reacts to new virus variants. Are mainly pre-existing memory B cells reactivated, or are new naive B cells also activated on a larger scale? This question is…
Recent COVID-19 booster vaccinations have demonstrated a strengthened defense against newer virus variants, according to a study published in Nature Communications. The research, conducted by a team of medical and scientific experts from TWINCORE, Hannover Medical School, and the German Primate Center, investigated the immune response in previously immunized individuals following vaccination with an mRNA vaccine tailored to the JN.1 variant.
The findings indicate that the immune system primarily adapts existing memory B cells to the new viral strain, rather than heavily relying on the activation of newly generated naive B cells. Following the booster vaccination, researchers observed increased antibody binding and improved neutralization of the JN.1 variant and subsequent virus variants.
Dr. Metodi Stankov, a research fellow at Hannover Medical School and one of the first two authors of the study, stated that initial responses were dominated by pre-existing cross-reactive memory B cells, while JN.1-specific B cells expanded later.
The study further revealed that somatic hypermutation, a natural maturation process of the immune system, played a crucial role in driving the specialization of antibody genes responsible for antigen binding. This process enhances variant-specific antibody affinity, indicating an adaptation of existing immune memory rather than the predominant activation of naive B cells.
Prof. Ulrich Kalinke, director of the Institute for Experimental Infection Research at TWINCORE, emphasized that this research provides a first step toward understanding how vaccine adaptation to new virus variants influences the immune response, using advanced methods to track the modulation of the immune response with greater precision.
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