The invention concerns immunogenic compositions prepared from preparations obtained by incubating first means expressing the target receptor(s) of an infectious pathogenic agent, with second means expressing at least the regions of the infectious pathogenic agent recognising said targets, in conditions enabling interaction between the first and second means so as to form a complex, the incubation being carried out according to different time intervals； and contacting the resulting complexes with a binding agent, for different time intervals, said first and second means being tolerated by mammals. The invention is useful for preparing vaccine compositions designed for mammals against an infectious pathology.
