Preparation of anti-polysaccharide antiserum using liposomes as immunological adjuvant

Bovine serum albumin (BSA) was coupled to dextran by controlled periodate oxidation followed by sodium borohydride reduction. The conjugate was entrapped in negatively charged, multilamellar phosphatidylcholine (lecithin) liposomes in which the polysaccharide remained surface-exposed, at least partially. Liposome-entrapped conjugate elicited in rabbits an appreciable anti-dextran response when compared with the sera raised in saline or in Freund's adjuvant. The anti-dextran antibodies belonged to both the IgM and IgG classes. The precipitin reaction of dextran with the antiserum raised in liposomes was determined.