Effects of intranasal administration with Bacillus�subtilis on immune cells in the nasal mucosa and tonsils of piglets

Abstract

The nasal mucosa is the body's first barrier against pathogens entering through the respiratory tract. The respiratory immune system of pigs has more similarities with humans than the mouse respiratory system does, and so was selected as the animal model in the present study. To evaluate the effects of Bacillus subtilis as a potential probiotic to stimulate local immune responses, piglets were intranasally administered with Dylight 488-labeled B. subtilis (WB800-green fluorescent protein). The results revealed that B. subtilis was able to reach the lamina propria of the nasal mucosa, nasopharyngeal tonsils and soft palate tonsils. Piglets were subsequently administered intranasally with B. subtilis (WB800) at 3, 12 and 28 days. The results revealed that, following administration with B. subtilis, the number of dendritic cells, immunoglobulin A+ B cells and T cells in the nasal mucosa and tonsils significantly increased (P<0.05). No obvious differences were observed in the morphological structure following B. subtilis administration. There were no statistical differences were observed in the expression of interleukin (IL)-1β, tumor necrosis factor-α and IL-8 mRNA between the B. subtilis treated group and the control group in the nasal mucosa, nasopharyngeal tonsil or soft palate tonsil. Toll-like receptor (TLR)-2 and TLR-9 mRNA expression in the tonsils was significantly increased following B. subtilis administration compared with the control group (P<0.05). The results demonstrate that B. subtilis administration increases the number of immune cells in the nasal mucosa and tonsils of piglets and stimulates nasal mucosal and tonsillar immunity. The present study lays the foundation for further study into the intranasal administration of B. subtilis in humans to enhance the immunity of human nasal mucosa to respiratory diseases.

Comparison of oral and nasal immunization with inactivated porcine epidemic diarrhea virus on intestinal immunity in piglets

“…B. subtilis has its own unique resistance properties, such as high temperature resistance, and can survive under extreme conditions ( 38 ). Previous studies have also indicated that the intranasal administration of B. subtilis may increase the number of dendritic cells and IgA-secreting cells as well as enhance the immune response in the nasal mucosa of piglets ( 39 , 40 ). Therefore, in the present study, B. subtilis was used as an immunopotentiator to elicit a stronger immune response after the vaccination of piglets with inactivated PEDV.…”

Variation in the response of bovine alveolar lavage cells to diverse species of probiotic bacteria

“…Most literature reports on Lactobacillus strains in disease prevention of pneumococcal infections [3] and Lactobacillus have been used to determine some of the mechanisms that reduce susceptibility in vitro [10]. However, Bacillus subtilis delivered intranasally increased TLR expression in tonsils of pigs [11]. Monocyte derived DCs were not affected in numbers or maturation by the soluble mediators of Lactobacillus rhamnosus, but their capacity to modulate T cell responses was enhanced [12].…”

Immunoactive preparations and regulatory responses in the respiratory tract: potential for clinical application in chronic inflammatory airway diseases

“…Topical probiotics also have the potential to modulate the immune system. Intranasal delivery of Bacillus subtilis in piglets resulted in increased expression of PRRs, increased numbers of DCs, B cells and T cells, as well as higher levels of IgA [63]. In a randomized trial of a nasal spray containing various lactobacilli and bifidobacteria there was no effect on symptom scores, microbiological flora, or inflammatory mediators.…”