RESUMEN
Sheep farming contributes to the socioeconomic development of small and medium-scale livestock farmers. However, several factors can hinder successful animal production, as is the case for infectious diseases, such as the one caused by Corynebacterium pseudotuberculosis, known as caseous lymphadenitis (CLA). CLA has >90% prevalence in Brazilian herds and antibiotic treatment is not effective, consequently causing significant economic losses to farmers. Given the above, effective vaccines need to be developed to prevent this disease. This study aimed to evaluate the adjuvant activity of the lipid extract from the macroalgae Iridaea cordata as a candidate for developing an effective vaccine formulation. For such, four groups of six sheep each were inoculated with sterile 0.9% saline solution (G1), rCP01850 (G2), rCP01850 + I. cordata (G3), and rCP01850 + saponin (G4). Each sheep received two vaccine doses 30 days apart. Total IgG production levels significantly increased in experimental groups G3 and G4 on days 30, 60, and 90. On day 90, G3 showed higher total IgG production (p < 0.05) when compared to G4. When analyzing cytokine production, G3 was the only experimental group with significantly increased IFN-γ, IL-12, TNF-α, and IL-10 mRNA expression levels. Our results show the vaccine formulation containing rCP01850 adjuvanted with the I. cordata lipid extract elicited a Th1 immune response in sheep, indicating I. cordata lipid extract may be a promising adjuvant for developing an effective vaccine against infection caused by C. pseudotuberculosis.
Asunto(s)
Adyuvantes Inmunológicos , Vacunas Bacterianas , Corynebacterium pseudotuberculosis , Enfermedades de las Ovejas , Células TH1 , Animales , Ovinos , Enfermedades de las Ovejas/prevención & control , Enfermedades de las Ovejas/inmunología , Adyuvantes Inmunológicos/administración & dosificación , Adyuvantes Inmunológicos/farmacología , Células TH1/inmunología , Corynebacterium pseudotuberculosis/inmunología , Vacunas Bacterianas/inmunología , Vacunas Bacterianas/administración & dosificación , Anticuerpos Antibacterianos/sangre , Anticuerpos Antibacterianos/inmunología , Citocinas/metabolismo , Citocinas/inmunología , Inmunoglobulina G/sangre , Infecciones por Corynebacterium/prevención & control , Infecciones por Corynebacterium/inmunología , Lípidos/inmunología , Brasil , Proteínas Bacterianas/inmunologíaRESUMEN
Caseous lymphadenitis is a chronic contagious disease that causes economic losses worldwide. Treatments are ineffective, thus demonstrating the importance of vaccination. In this study, rNanH and rPknG proteins from Corynebacterium pseudotuberculosis were associated with saponin or aluminum hydroxide adjuvants. Three experimental groups (10 animals each) were immunized with sterile 0.9% saline solution (G1), rNanH + rPknG + Saponin (G2), rNanH + rPknG + Al(OH)3 (G3). The mice received two vaccine doses 21 days apart. Animals were challenged 21 days after the last immunization and evaluated for 50 days, with endpoint criteria applied when needed. The total IgG production levels of the experimental groups increased significantly on day 42 when compared to the control (p < 0.05). When tested against rNanH, G2 had a better rate of anti-rNanH antibodies compared to G3. In the anti-rPknG ELISA, the levels of total IgG, IgG1, and IgG2a antibodies were higher in G2. The vaccines generated partial protection, with 40% of the animals surviving the challenge. The association of recombinant NanH and PknG proteins led to promising protection rates in mice, and although using different adjuvants did not interfere with the survival rate, it influenced the immune response generated by the vaccine formulations.
RESUMEN
Caseous lymphadenitis (CLA) is an infectious disease that affects goats and sheep causing drastic impacts on milk and meat production and is caused by Corynebacterium pseudotuberculosis. The disease can be prevented through vaccination but currently, vaccines demonstrate limited efficacy consequently leading to a need for the development of new ones. Here, we described the in silico development of a new chimeric protein constructed with epitopes identified from the sequences of the genes nanH, pknG, spaC, and sodC, previously described as potential vaccinal targets against C. pseudotuberculosis. The chimera was expressed, purified, and its immunogenicity was evaluated using sera of immunized mice. Results indicate the chimeric protein was able to stimulate antibody production. Additionally, analysis using serum from naturally infected goats showed that the protein is recognized by sera from these animals, indicating the possibility for using this chimera in new diagnostic methods. KEY POINTS: ⢠The chimera was expressed with 52 kDa and a yield of 7 mg/L after purification. ⢠The chimera was recognized by the sera of animals immunized with this formulation. ⢠Chimera reacted with the serum of goats naturally infected with C. pseudotuberculosis.