What this work is about, in plain words
"Trained immunity" is the ability of innate immune cells to "remember" an encounter with a stimulus and then respond more strongly. The authors tested whether extracts of cyanobacteria and microalgae cause such reprogramming.
Macrophages are cells of innate immunity. After encountering certain substances, such as the BCG vaccine or β-glucan, they reprogram their metabolism and respond more strongly at the next encounter. This phenomenon is called "trained immunity". The authors tested whether extracts of cyanobacteria and microalgae can cause it.
Six cultures were used: the cyanobacteria Leptolyngbya cf. ectocarpi, Planktothrix agardhii, Arthrospira platensis and Roholtiella mixta, the diatom Nanofrustulum shiloi and the green alga Tetraselmis viridis. Extracts were prepared from dry biomass in a DMSO solution. Macrophages were taken from the abdominal cavity of C57Bl/6 mice — either ordinary ones or ones "primed" in advance by injecting the BCG vaccine or a starch solution. The extracts were added to them in vitro, sometimes together with bacterial lipopolysaccharide, and glycolysis and the production of lactate, nitric oxide and reactive oxygen species were measured.
According to the authors, the extracts partly enhanced glycolysis and markedly increased nitric oxide production, but did not cause the metabolic reprogramming of macrophages typical of trained immunity. The response depended on the alga species and on how the cells had been "primed".
Limitations. Experiments on mouse cells in vitro. This is a study of mechanisms, not proof of an effect on human immunity. The results were obtained by the authors of the article and do not describe Laboratory 17 materials.