LS5 group shows significantly higher antibody response compared to OVA alone

LS5 group shows significantly higher antibody response compared to OVA alone. fed to mice. LSs stimulated significantly higher anti-OVA serum IgG and fecal IgA antibodies compared to those induced by use of cholera Dexloxiglumide toxin as a positive-control adjuvant. The antibody response was not affected by pre-neutralization of the stomach acid, and persisted for up to seven months. Confocal microscopy revealed that LSs can translocate in to mouse intestinal wall. Overall, this study lays the foundation of using LSs as a novel approach for oral vaccination. Keywords:lycopodium spores, mucosal vaccination, oral vaccination, pollen shells, sporopollenin == 1. Introduction == Oral vaccination is usually of significant interest because it is usually needle-free, painless, child-friendly, convenient, and amenable to self-administration. Furthermore, antigen delivery to the gastrointestinal tract has potential to induce mucosal immunity through antigen-processing via the gut-associated lymphoid tissues [1,2]. Because majority of pathogens infect via mucosal surfaces, immunological defenses at mucosal surfaces can neutralize pathogens before they can cause contamination [3]. However, oral vaccination remains daunting because the vaccine molecules experience a highly degradative environment in the stomach, and encounter a tough transport barrier offered by the tightly juxtaposed epithelial cells that line the intestinal mucosa [4]. To overcome these delivery challenges, live attenuated microorganisms such as bacteria and viruses, and particulate vaccine delivery systems such as liposomes, virosomes, polymeric micro and nanoparticles, and immune stimulating complexes have been examined [5,6]. Various techniques that seek to target microfold (M) cells to enable higher antigen uptake through endocytosis have also been tested [7]. Toxins such as cholera toxin (CT) and heat labile enterotoxin (LT) that enable increased uptake of vaccine molecules have demonstrated the highest adjuvant effects [8,9]. However, the toxicity of CT and LT naturally renders them unsuitable for human use [10]. The dangers of attenuated yet live strains of viruses and bacteria to become virulent, or their neutralization through pre-existing host immunity are some of the limitations of using microorganisms for oral vaccination [11]. Additionally, low encapsulation efficiency of antigens in polymeric particles, and poor vaccine stability resulting from exposure to organic solvents during particle synthesis Dexloxiglumide has hindered clinical use of polymeric particles [12]. Plant-based edible vaccines expressed in rice [13], tobacco, tomato, carrot and potato have also been investigated [14]. Based on a twenty year development experience of an edible Dexloxiglumide vaccine against hepatitis B, it has been found that just oral administration of edible plant-based hepatitis vaccine was insufficient for a protective response, yet when coupled in an oral-parenteral dosage Dexloxiglumide regimen, it proved to be effective [14]. In this study we propose a novel concept to use pollen grains (PGs) as a natural system for oral vaccination. In nature, PGs facilitate pollination by functioning as a safety-pod to carry the plant male gamete to the female reproductive organ, the ovary, located in the flower. During pollination PGs are often exposed to fluctuating temperatures and weather conditions, and to survive such conditions, they possess mechanical toughness and chemical resistance. Our postulate to use PGs for oral vaccination is based on such multiple natural properties of PGs that suggest their usefulness for oral vaccination: (i) they have a tough outer shell that can stay intact in the stomach environment [15,16], (ii) the shell is usually naturally porous, and (iii) despite their relatively large size (tens of m in diameter) it has been found thatLycopodium clavatum(clubmoss) spores (LSs) andSecale cereale(rye) pollen grains can cross the intestinal barrier as intact particles [17,18]. Thus overall, we hypothesized that if (i) natural pores in the pollen wall could be used to clean and remove the allergy-causing native biomolecules from PGs, (ii) their clean belly could be refilled with vaccine antigens through the natural pores in pollen walls, and (iii) the antigen-filled PGs could translocate across the intestinal epithelium into the body, then PGs might behave as natural Trojan horses KLF4 antibody for oral vaccination ferrying the vaccines safely into the body..