The present invention relates to a pharmaceutical composition comprising at least one vaccine antigen, which also comprises at least one phosphoric ester derivative of phosphatidylcholine having the structure: ##STR00001## in which: R.sub.1 is a lower alkyl, R.sub.2 and R.sub.3 are identical or different, and can each represent linear hydrocarbon-based chains having from 13 to 21 carbon atoms.