ABOVE: © TERESE WINSLOW
While researchers have observed for decades that certain vaccines seem to help recipients ward off more than just the target pathogen, only in recent years have they identified possible mechanisms for these bonus benefits. For example, in a study published this year (depicted here), researchers examined immune cells from the blood and bone marrow of healthy adults before and after they received a live tuberculosis vaccine known as bacille Calmette-Guérin, or BCG.
In the bone marrow post-vaccination, genes are expressed that trigger hematopoietic stem and progenitor cells to differentiate into monocytes, neutrophils, and other so-called myeloid cells. In a separate analysis of the effects of BCG in newborns, the researchers found that the vaccine ramped up the number of neutrophils in babies’ blood compared with unvaccinated infants.
Monocytes from the blood displayed epigenetic changes after vaccination that opened chromatin harboring multiple genes involved in driving an ...