Algae-based oral recombinant vaccines

Elizabeth A Specht,Stephen P Mayfield

doi:10.3389/fmicb.2014.00060

Elizabeth A Specht, Stephen P Mayfield

Open Access

https://doi.org/10.3389/fmicb.2014.00060

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Abstract

Recombinant subunit vaccines are some of the safest and most effective vaccines available, but their high cost and the requirement of advanced medical infrastructure for administration make them impractical for many developing world diseases. Plant-based vaccines have shifted that paradigm by paving the way for recombinant vaccine production at agricultural scale using an edible host. However, enthusiasm for “molecular pharming” in food crops has waned in the last decade due to difficulty in developing transgenic crop plants and concerns of contaminating the food supply. Microalgae could be poised to become the next candidate in recombinant subunit vaccine production, as they present several advantages over terrestrial crop plant-based platforms including scalable and contained growth, rapid transformation, easily obtained stable cell lines, and consistent transgene expression levels. Algae have been shown to accumulate and properly fold several vaccine antigens, and efforts are underway to create recombinant algal fusion proteins that can enhance antigenicity for effective orally delivered vaccines. These approaches have the potential to revolutionize the way subunit vaccines are made and delivered – from costly parenteral administration of purified protein, to an inexpensive oral algae tablet with effective mucosal and systemic immune reactivity.

Highlights

Infectious diseases directly account for nearly 25% of deaths worldwide, and are a predominant cause of morbidity and mortality in the developing world (Fauci et al, 2005)
Oral vaccines obviate the need for trained medical personnel to administer them and reduce the risks of infection associated with needles
While vaccine antigens have been transformed into many edible species including lettuce, tomato, potato, and tobacco, expression in stable transformed crop plants has suffered from low yields, typically less than 1% of total soluble protein (TSP; Lossl and Waheed, 2011)

Summary

INTRODUCTION

Infectious diseases directly account for nearly 25% of deaths worldwide, and are a predominant cause of morbidity and mortality in the developing world (Fauci et al, 2005). Many developing world diseases do not yet have vaccines, in part because traditional vaccine production costs present a significant investment hurdle, considering the financial capacity of the intended consumers. Both cost and ease of administration are challenges that must be tackled to address this undue burden on global health and productivity. Oral vaccines obviate the need for trained medical personnel to administer them and reduce the risks of infection associated with needles. They have higher compliance from patients, owing to the lack of fear and resistance associated with injections.

Specht and Mayfield

Significant findings

Findings

Angiotensin II fused to