A $200,000 grant from the World Health Organization will enableCambridge Biotech Corp., of Worcester, Mass., to test its QS-21booster molecule in two anti-malaria vaccines developed by the WalterReed Army Institute of Research, in Washington, D.C.An initial 12-month down payment of $75,000 will tool upCambridge's research project, which starts in September 1994, withpersonnel, animal models and equipment.QS-21, trademarked Stimulon, is a vaccine adjuvant which heightensthe immune system's response to target antigens.Initially, the company will combine QS-21 with Walter Reed'sproprietary molecule, EBA-175. This protein is the receptor that ushersthe Plasmodium falciparum parasite's erythrocytic stage from the liverinto red blood cells. "QS-21 is a strong inducer of cell-mediatedimmune responses by the body," said Cambridge's Oscar Kashala,"including cytotoxic T cells, a key component to protection againstmalaria." Kashala is the company's director of medical affairs (tropicaldiseases).
SubeadQS stands for Quillaja saponaria, "a tropical tree from the bark ofwhich Cambridge extracted an antigen-active fraction with potentadjuvant activity and little toxicity," Alyson Button Stone,Cambridge's coordinator of investor relations, told BioWorld. QS-21was discovered and purified by Charlotte Kensil, the firm's director ofadjuvants and drug delivery.Most of the adjuvant/antigen research will take place at Cambridge,Stone said, with smaller-scale primate studies at Walter Reed'sdepartment of immunology.Walter Reed's immunologist Ripley Ballou is in Thailand right nowdirecting a trial of the vaccine _ not yet including QS-21 _ in 1,300children. "The 2-mg dose," said his colleague, David Lanar, "is terriblyexpensive to synthesize." He told BioWorld, "we're looking to QS-21to give our vaccine the same antigenic effect with one-thousandth thedose."Besides evaluating the adjuvant's efficacy in boosting antigenicprowess in a potential vaccine, Cambridge's grant from WHO'stropical disease research and training program covers training scientistsand post-docs from malaria-endemic regions of the world in thecompany's Molecular Pathogenesis Laboratory.
-- David N. Leff Science Editor
(c) 1997 American Health Consultants. All rights reserved.