Abstract: The invention relates to immunogenic complexes such as two-dimensional lamellae having a honeycomb structure and in particular three-dimensional iscoms, which immunogenic complexes are composed of at least one sterol, one saponin and, in the case of iscoms, also a phospholipid and also, optionally, at least one antigen generating an immune reaction. The saponin used is at least one of the fractions which are derived from Quil A by means of hydrophobic interaction chromatography and have the designations QA 1 to QA 23, as is shown in the figure by the numerals 1 to 23. Preferably, the saponin used is one or more of the fractions derived from Quil A having the designations QA 3, QA 17 and QA 23.

Abstract: The invention relates to new oligosaccharides comprising the structure (D-ribose-D-ribitol-phosphate).sub.m, (D-ribitol-phosphate-D-ribose).sub.m or (phosphate-D-ribose-D-ribitol).sub.m, m being 2,3,4 . . . 19 or 20, to immunogens containing such oligosaccharide, to vaccines containing such immunogens and to methods for preparing such oligosaccharides, immunogens and vaccines. The vaccine is very suitable for treating infections caused by Haemophilus influenzae type b.

Abstract: The invention relates to a new vaccine comprising a native protein capable of inducing the production of protective antibodies in a host, together with an adjuvant amount of certain proteins or peptides which, as such, are not capable of inducing substantial protective antibody titres but considerably enhance the immunizing activity of said native protein.The amino acid sequences of the adjuvant proteins and peptides show homology with the native proteins. Combination of inactivated picornavirus, such as poliovirus, with adjuvant amounts of denatured picornavirus, such as poliovirus, capsis proteins, in a vaccine, is highly advantageous.

Abstract: The invention relates to a process for preparing immunogenic complexes in which an amphiphatic antigenic protein or peptide in dissolved or solubilized form is contacted with a solution containing a detergent, a sterol, and a glycoside comprising hydrophobic and hydrophilic regions, in at least the critical micelle forming concentration, the detergent is removed, and the immunogenic complex formed is purified. Optionally, the solution with which the antigenic protein or peptide is contacted also contains a phospholipid, preferably phosphatidylethanolamine. The preferred sterol is cholesterol, and preferred glycosides are saponins, espeically Quil A.The immunogenic complex is useful as a vaccine. Its immunogenic power is higher than that of corresponding micelles formed by aggregation of the antigens, and is also higher than that of the antigens incorporated in liposomes.