Low-Cost Vaccines

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Summary Enteric disease and respiratory diseases are major problems worldwide which greatly impact human health, as well as animal health. Current vaccine approaches are limited by numerous factors, including production costs, efficacy, safety, requirement of adjuvants, and storage conditions.    Description UCSD researchers have engineered diatoms (algae) to express pathogenic antigens on the cell surface, which induce protective immunity suitable for use as vaccines against such pathogens. In addition to providing an expression platform, the diatom structure provides an endogenous adjuvant activity.    Applications Algae-based vaccines could provide a broadly based, completely new, innovative, inexpensive high production vaccine system for numerous infectious diseases, including bovine respiratory disease, which causes significant economic losses for the cattle industry.    Advantages Traditional vaccine approaches have many limitations. For example, killed pathogen vaccines are expensive, require additional adjuvants, multiple doses, and often have undesirable side effects. Live modified or recombinant attenuated bacterial or virus vectored vaccines may revert to virulence. In contrast, algae-based vaccines expressing an antigen may be less expensive, and carry endogenous adjuvant activity.    Development UCSD researchers have preliminary data demonstrating in vitro that the diatoms stimulate monocytes in peripheral blood to produce TNF alpha. These data indicate that immune responses are stimulated by the algae, as seen by activation of these early antigen presenting cells.  In addition, researchers have generated expression vectors and demonstrated expression of foreign proteins on the algae cell surface, as well as high level intracellular expression.