House of innate lymphocytes

Conventional or classical T-cells are thought of as adaptive immune cells because they adapt to a particular infection. The immune response they mount is highly specific to a given pathogen—be it a bacterium, a virus, a fungus or a parasite. It can take days for this response to develop, and the cells in question respond specifically to small protein bits or peptide antigens in order to get activated.

A few years ago the idea of ‘innate T-cells’ would have been laughed out as an oxymoron of sorts. Yet, innate T-cells are rapidly revealing themselves to be instrumental in both immune defence as well as homeostasis. In many ways, innate T-cells represent a variation on the long-appreciated themes of conventional T-cell activation and function: innate T-cells recognise pathogen-associated entities, but these needn’t strictly be peptides: they can be lipids, sugar-lipid hybrids, and other complex biochemical products of metabolism. Innate T-cells are specific in their responses to pathogens, but they respond faster—within minutes of activation—essentially buying time for conventional adaptive T-cells to get activated.

The three main innate T-cell subsets include: invariant Natural Killer T (iNKT) cells, gd (gamma-delta) T-cells and Mucosa-associated Invariant T (MAIT) cells. Thanks to soon to be Dr Sharma for creating and adding this House!