A First Pass at Artificial Cell Structures Capable of Influencing the Immune System
I think it a little much to be calling the artificial cell structures reported here T cells; the similarities are few. They are pseudo-cell-like membranes that can be decorated with surface features capable of interacting with other cell populations. The goal touted here is to influence the immune system, but in principle any sort of cell to cell communication that relies on surface decoration could be targeted in this way. Being able to build membranes that can pass for cells in the body, and thus avoid the attention of the immune system, seems more useful for the ability to hide molecular machinery inside them, however. Plasmids that can generate specific proteins, for example - a great deal might be accomplished with the ability to introduce durable protein factories into a specific tissue.
Researchers have developed synthetic T lymphocytes, or T cells, that are facsimiles of human T cells. Such cells could eventually be used to boost the immune system of people with cancer or immune deficiencies. Natural T cells are difficult to use in research because they're very delicate, and because after they're extracted from humans and other animals, they tend to survive for only a few days. "We were able to create a novel class of artificial T cells that are capable of boosting a host's immune system by actively interacting with immune cells through direct contact, activation, or releasing inflammatory or regulatory signals. We see this study's findings as another tool to attack cancer cells and other carcinogens."
The team fabricated T cells using a microfluidic system. They combined two different solutions - mineral oil and an alginate biopolymer, a gum-like substance made from polysaccharides and water. When the two fluids combine, they create microparticles of alginate, which replicate the form and structure of natural T cells. The scientists then collected the microparticles from a calcium ion bath, and adjusted their elasticity by changing the concentration of calcium ions in the bath.
Once they had created T cells with the proper physical properties, the researchers needed to adjust the cells' biological attributes - to give them the same traits that enable natural T cells to be activated to fight infection, penetrate human tissue, and release cellular messengers to regulate inflammation. To do that, they coated the T cells with phospholipids, so that their exterior would closely mimic human cellular membranes. Then, using a chemical process called bioconjugation, the scientists linked the T cells with CD4 signalers, the particles that activate natural T cells to attack infection or cancer cells.
Link: https://www.eurekalert.org/pub_releases/2018-06/uoc--rds062618.php