Magalhães T, Viotti A P, Gomes R T, de Freitas T V
Centro de Pesquisa e Desenvolvimento, Fundação Ezequiel Dias (FUNED), Rua Conde Pereira Carneiro 80, Belo Horizonte CEP 30510-010, Minas Gerais, Brazil.
Biotechnol Appl Biochem. 2001 Apr;33(2):61-4. doi: 10.1042/ba20000080.
Crotoxin isolated from the venom of Crotalus durissus terrificus (South American rattlesnake) was incorporated into liposomes by the dehydration-rehydration vesicle method using different membrane compositions and the co-encapsulation of immunostimulants. Crotoxin was also encapsulated into liposomes formed from a non-phospholipid amphiphile, a mixture of polyoxyethylene 2-cetyl ether, dicetyl phosphate and cholesterol. The preparations were characterized in relation to stability, toxicity and the protection of mice against whole venom after immunization. All liposome preparations were quite stable, retaining more than 75% of the originally encapsulated crotoxin after 1 week of incubation at physiological temperature. Co-encapsulation with lipopolysaccharide increased the leakage of crotoxin. In contrast, co-encapsulation of the lipid moiety of lipopolysaccharide did not influence the stability of liposomes. Toxicity of liposomes was dependent on membrane composition. Liposomes made with phospholipids that were resistant to phospholipase A(2) activity were less toxic. Mice immunized with three doses of the 1 x LD50 of crotoxin encapsulated into liposomes, and with associated immunostimulants, were protected against challenge with 8 x subcutaneous LD50 of C. durissus terrificus venom. Using the same immunization schedule, liposomes made from a non-phospholipid mixture and without immunostimulants achieved 100% protection.
从南美响尾蛇（Crotalus durissus terrificus）毒液中分离出的响尾蛇毒素，通过脱水再水化囊泡法，利用不同的膜成分和免疫刺激剂的共包封，被包封到脂质体中。响尾蛇毒素也被包封到由非磷脂两亲物、聚氧乙烯2-十六烷基醚、磷酸二鲸蜡酯和胆固醇的混合物形成的脂质体中。对这些制剂的稳定性、毒性以及免疫后对小鼠抵御全毒液的保护作用进行了表征。所有脂质体制剂都相当稳定，在生理温度下孵育1周后，仍保留超过75%最初包封的响尾蛇毒素。与脂多糖共包封会增加响尾蛇毒素的泄漏。相比之下，脂多糖脂质部分的共包封并不影响脂质体的稳定性。脂质体的毒性取决于膜成分。由对磷脂酶A(2)活性有抗性的磷脂制成的脂质体毒性较小。用三剂包封在脂质体中的1倍半数致死剂量（LD50）的响尾蛇毒素以及相关免疫刺激剂免疫的小鼠，能抵御8倍皮下注射LD50的南美响尾蛇毒液的攻击。使用相同的免疫方案，由非磷脂混合物制成且无免疫刺激剂的脂质体实现了100%的保护。
