Synthesis of a Structurally Defined Antigen-Immunostimulant Combination for Use in Cancer Vaccines
作者:Wulf Dullenkopf、Gerd Ritter、Sheila R. Fortunato、Lloyd J. Old、Richard R. Schmidt
DOI:10.1002/(sici)1521-3765(19990802)5:8<2432::aid-chem2432>3.0.co;2-5
日期:1999.8.2
Ganglioside GM(2) expressed on the cell surface of human cancers is a promising target for immunotherapy because GM(2) antibodies are cytotoxic in vitro and GM(2) antibody formation can be induced upon vaccination in cancer patients. We recently reported on the efficient chemical synthesis of GM(2); clinical trials with these synthetic GM(2) conjugated to a purified carrier protein (KLH) are currently under way. In our efforts to generate a totally synthetic GM(2) cancer vaccine, we have now synthesized GM(2) neoglycolipid 1, which consists of the GM(2)-tetrasaccharide epitope that is linked through a spacer to the B-cell stimulatory glycolipid 4. Target compound 1 was constructed from the GM(2) tetrasaccharide donor 2, the 9-hydroxynonanoate 3 spacer, and the 6-amino-6-deoxy derivative (5) of compound 4. Building block 5 was obtained from Z-protected 6-azido-6-deoxy-N-leucyl-glucosamine derivative 12, which was available from glucosamine by two different approaches; the route with the Z-protected derivative of 4 (10) as intermediate gave the best yields, The neoglycolipid 1 reacted with a number of different GM(2)-reactive antibodies. Vaccination of rabbits with 1 resulted in induction of antibodies against GM(2), thus confirming the viability of this novel concept far the construction of a totally synthetic vaccine.