Can bee venom be microencapsulated within liposomes?
Tatiana Cristina Silvaa, b, Vanessa de Almeida Silvaa, b, Antônio Carlos Lopes
and Maria Helena Bueno da Costaa
aLab. de Microesferas e Lipossomas – C. de Biotecnologia - Av. Vital Brasil, 1500, 05503-900 – Butantan, São Paulo, SP, Brasil; b Dep. de Clínica Médica UNIFESP Universidade Federal de São Paulo São Paulo, SP, Brasil
For individuals with a specific allergy to Hymenoptera bites, the venom immunotherapy (VIT) may be a relatively effective treatment option. Treatments failures do however occur and VIT may cause frequent systemic allergic side effects, mainly in honeybee venom allergy persons. The Immunotherapy is expensive and time consuming. New strategies to improve safety and efficacy of this treatment are therefore of general interest. We propose here a systematic approach to study the basic and biotechnological problems related with the development of safe formulations of bee venoms within liposomes to be used in VIT. Liposomes could increase the immunogenic capacity, decrease the toxicity and decrease the quantity and frequency of the venom doses during the VIT. However, bee venom mellitin and phospholipase destruct the phospholipid membranes. Our central idea® in modifying the VIT is the combination of three different tools: encapsulation of chemically modified venoms within stabilized liposomes.Here we present the results of the interaction of modified bee venom (BVm) with artificial membranes.
The liposome turbidity of formulation containing pbb (inhibitor) within the lipid membrane was constant during their incubation with BVm. This fact was interpreted as 100 % of protection against aggregation. In contrast it was observed 90 % of protection in incubations of BVm with pbb membrane free.
It was observed 62 % of rodamine leak out from those liposomes pbb free and incubated with BVn (native bee venom). We strongly believe that this formulation will be non toxic and that its immunogenicity will be retained. We expected that less quantities of the antigen will be required to obtain the same benefits in venom immunotherapy.
Grants: FAPESP (05/04514-2 and 00/14228-3) CNPq (491171/2005-6) and CAPES.
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