Squalene alone is not an adjuvant, but emulsions of squalene with surfactants enhance the immune response when added to antigens.

NKT cells are hybrids: they kill invading microbes, like natural killer immune cells, but they also bind to antigens - foreign substances that trigger an immune response - like T-cells do.

It is generally accepted that normal immune response to extrinsic antigens depends on coordinating interaction between t cells and antigen presenting cells (APCs).