Oral vaccination of piglets against Mycoplasma hyopneumoniae using silica SBA-15 as an adjuvant effectively reduced consolidation lung lesions at slaughter

Abstract

Mycoplasma (M.) hyopneumoniae is the main pathogen of porcine enzootic pneumonia (PEP). Its controlling is challenging, and requires alternative strategies. This study aimed to develop an oral vaccine against M. hyopneumoniae using a nanostructured mesoporous silica (SBA-15) as an adjuvant, and compare its effect with an intramuscular (IM) commercial vaccine (CV). Fifty 24 day-old M. hyopneumoniae-free piglets composed five equal groups for different immunization protocols, consisting of a CV and/or oral immunization (OI). Control piglets did not receive any form of immunization. All piglets were challenged with M. hyopneumoniae strain 232 on D49 by tracheal route. IgA antibody response in the respiratory tract, bacterial shedding and serum IgG were evaluated. The piglets were euthanized on 28 (D77) and 56 (D105) days post-infection. Lung lesions were macroscopically evaluated; lung fragments and bronchoalveolar fluid (BALF) were collected for estimation of bacterial loads by qPCR and/or histopathology examination. All immunization protocols induced reduction on Mycoplasma-like macroscopic lung lesions. IgA Ab responses anti-M. hyopneumoniae, the expression of IL-4 cytokine and a lower expression of IL-8 were induced by CV and OI vaccines, while IgG was induced only by CV. Oral immunization using silica as a carrier-adjuvant can be viable in controlling M. hyopneumoniae infection.

Influence of Mycoplasma hyopneumoniae natural infection on the respiratory microbiome diversity of finishing pigs

“…Accordingly, previous studies have shown that animals infected with M. hyopneumoniae have a predominance of the species over other species, reducing bacterial diversity in the lung [ 9 , 27 ]. It is known that M. hyopneumoniae stimulates the immune system, generating the release of various pro-inflammatory cytokines [ 28 – 31 ], induces apoptosis [ 32 ], nitric oxide stimulation [ 33 ], which promote lung damage in infected individuals. Likewise, lung damage was also observed in the present study, as animals positive for M. hyopneumoniae had a higher degree of pulmonary involvement.…”

Use of Nanostructured Silica SBA-15 as an Oral Vaccine Adjuvant to Control Mycoplasma hyopneumoniae in Swine Production

“…A lower degree of lung injury, associated with the increase in IgA levels in animals that received the oral vaccine, was observed in animals that received the new vaccine in the previously conducted study [ 16 ]. In the present study, vaccinated piglets also showed a lower degree of lung injury, regardless of the vaccination protocol.…”

“…There is still little data in the literature regarding the use of SBA-15 associated with antigens in the composition of oral vaccines, especially for animals such as the one produced in the present study. A previous study of characterization and use of the same oral vaccine under laboratory conditions of controlled infection showed promising results in stimulating immunity and reducing lung lesions at slaughter [ 16 ].…”

“…It is possible to observe, analyzing the plots and the recorded values, that such differences are present in the four groups, although there are indications that in G2 and G4, such temperature variation may have occurred more mildly when compared to the others. It was previously observed that the application of the oral vaccine acted in the modulation of the cellular immune response with an increase in the concentrations of anti-inflammatory cytokines, which was indicated as an effect possibly related to a lower incidence and extent of lung lesions in vaccinated animals [ 16 ].…”

“…A specific oral vaccine against M. hyopneumoniae, using the adjuvant carrier SBA-15 has been developed, demonstrating its capacity to stimulate the immune system associated with the intestinal mucosa, showing promising results with the decrease in the extent of lung lesions at slaughter in animals experimentally challenged with a homologous strain (232) used in the vaccine composition [ 16 ].…”