Polysaccharides complete antigens

Whilst macromolecules (proteins, peptides, dex-tran polysaccharides) can act as complete antigens, most drugs are simple chemicals (mol. wt less than 1000) and act as incomplete antigens or haptens, which become complete antigens in combination with a body protein. 

Although the function of complex polysaccharides of bacterial cells remains to be found, these substances seem to be necessary for feral bacterial life, since they are dispensable, as in rough forms which appear in the non-competitive life in vitro and which generally outgrow the smooth form but, despite the fact that the change is essentially irreversible, freshly iso-ated cells are antigenically complete. 

Boyden and Sorkin, in an excellent review on antigens of Mycobacterium tuberculosis, think that it is still not completely clear whether antibodies are formed against any of the lipid molecules, as distinct from polysaccharide or protein components of lipidic complexes. ... 

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