From Freunds Adjuvant to MDP

Freund s adjuvant (mycobacterial cells in a water-in-oil emulsion containing the antigen in the water phase) (75) is used for stimulating the production of antibodies against the antigen used. A five to ten fold titer of antibodies is obtained with complete Freund s adjuvant in comparison with incomplete adjuvant lacking Mycobacteria. It also induces delayed hypersensitivity to the antigen (9, 72). 

The active compounds in Mycobacteria, which are responsible for their immunostimulant activity are part of the cell wall which is a macro-molecular insoluble net-work having two distinctly different components the peptidoglycan (Fig. 1) and a mycolate of an arabinogalactan. These are linked by phosphodiester bridges. 

This same structure is shown in a simplified manner in the lower left part of Fig, 2, which illustrates a hypothetical structure of the mycobacterial cell wall, in which mycolic acids Myc are esterified to an arabinogalactan. The latter is itself linked by a phosphodiester bridge to the peptidoglycan 40, 41). 

It has been known since 1958 that the chloroform soluble Wax D  

It was believed for a long time that biological activity was due essentially to the mycolic acids as typical constituents of mycobacteria. 

---