Lipopeptides

Lipoproteins are part of the outer membrane of Gram negative bacteria, Gram positive bacteria, and mycoplasma. Bacterial - including mycoplasmal - lipoproteins (bLP) are characterised by the unusual amino acid dihydroxypropylcysteine (Dhc) acylated by two or three fatty acids. 

Synthetic analogues (sLP) and the N-terminal part of the lipoprotein of E.coli act as potent immunoadjuvants in vivo and in vitro. Immunisation of guinea pigs and swine with a totally synthetic vaccine consisting of the built-in lipotripeptide adjuvant Pam3Cys-Ser-Ser and of a B and T cell epitope of the foot-and-mouth disease virus lead to a long-lasting protection against virus challenge.
The conjugation of class I restricted peptides with Pam3Cys-Ser-Ser resulted in efficient priming of virus-specific cytotoxic T cells for the first time in 1989.

The outer membrane lipoprotein (OspA) from Borrelia burgdorferi was used in human vaccine trials and proved to be protective in a mouse model even after oral immunisation.