ADJUVANT ACTIVITY OF NONTOXIC QUILLAJA-SAPONARIA MOLINA COMPONENTS FOR USE IN ISCOM MATRIX

It is well established that ISCOMs function efficiently as an antigen- presenting system and protective immunity has been evoked against a va riety of infectious agents. The built-in saponin adjuvant from Quillaj a saponaria Molina is responsible for the strong immunoenhancing activ ity displayed by the ISCOM. However, to allow the use of ISCOMs in hum an vaccines it is necessary to determine the immunological properties and toxicity of chemically defined Quillaja components. Thus, the pres ent study was carried out in a mouse model to determine the adjuvant a ctivity and toxicity of ''free'', isolated Quillaja components, as wel l as formulated into particles, i.e. ISCOM matrix. The purified Quilla ja components and the ISCOM matrix formulations were examined for thei r adjuvant activity in a model system consisting of purified influenza virus antigen and Quillaja saponins. It was demonstrated that a Quill aja component, designated QH-C, either as a ''free'' component or in a n ISCOM matrix, has a strong adjuvant activity, but little or no toxic ity in the doses tested. In addition, QH-C in the form of ISCOM matrix does not induce any local reactions at the sire of injection. Thus, I SCOMs containing the QH-C component, devoid of toxicity, but with stro ng adjuvant activity, can prove to be useful in adjuvant formulations for human use.