Gut microbiota may be the key factor explaining why certain individuals do not respond well to the pneumococcal vaccine, a bacterium that can cause various diseases, such as pneumonia. This conclusion is drawn from a recent study led by the B Cell Biology Research Group at the Hospital del Mar Research Institute, published in Science Advances.
Researchers analyzed vaccine responses using genetically modified mouse models to study two types of pneumococcal vaccines-one commonly used in children and another in adults. Although these vaccines function through different mechanisms, both provide broad coverage.
However, in individuals with a specific type of immunodeficiency, immunoglobulin A (IgA) deficiency, the immune system does not always mount an adequate response, leaving them vulnerable to respiratory infections that can lead to severe complications. The reason: poor regulation of gut microbiota.
IgA plays a crucial role in controlling gut microbiota. It regulates its function and ensures that its presence remains beneficial to the body. However, in the absence of IgA, the bacteria that make up the microbiota can overgrow and spread beyond the intestines.
This overgrowth triggers an immune system response to keep the bacteria in check, but this response remains persistently active over time, leading to immune cell exhaustion.
By Hospital del Mar Medical Research Institute
Article can be accessed on: phys.org