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Humoral and cellular immune responses in mice against secreted and somatic antigens from a C orynebacterium pseudotuberculosis attenuated strain: Immune response against a C. pseudotuberculosis strain

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ABSTRACT

Background: Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis (CL), a chronic disease that affects goats and sheep. CL is characterized by the formation of granulomas in lymph nodes and other organs, such as the lungs and liver. Current knowledge of CL pathogenesis indicates that the induction of humoral and cellular immune responses are fundamental to disease control. The aim of this study was to evaluate the humoral and cellular immune responses in BALB/c mice inoculated with a C. pseudotuberculosis strain isolated in the state of Bahia, Brazil.

Results: The lymphocyte proliferation and in vitro production of IFN-γ, IL-4, IL-10, IL-12 and nitric oxide by spleen cells stimulated with secreted and somatic antigens from the studied strain were evaluated. IgG subclasses were also analyzed. Results showed a significant increase of Th1-profile cytokines after 60 days post-inoculation, as well as an important humoral response, represented by high levels of IgG2a and IgG1 against C. pseudotuberculosis.

Conclusion: The T1 strain of C. pseudotuberculosis was shown to induce humoral and cellular immune responses in BALB/c mice, but, even at a dosage of 1x107 CFU, no signs of the disease were observed.

No MeSH data available.


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Serum IgG immune response in mice inoculated with T1 C. pseudotuberculosis strain, as evaluated by ELISA. Graph represents means of Optical Density (OD) values found for each group (n = 5 animals for group). Results are representative of the mean values obtained from two experiments. a. BALB/c mice were inoculated with increasing dosages: 5x105, 1x106, 5x106 and 1x107 CFU. Blood was collected 120 days after inoculation. Data were analyzed by ANOVA and Tukey post-hoc tests; *, †, ‡ and § indicate pairs with statistically significant differences. b. IgG subclass (IgG1, IgG2a, IgG2b and IgG3) production throughout the course of the experiment: control (before infection), 7, 30, 60, and 120 days after infection. Mice were inoculated with 107 CFU of T1 strain of C. pseudotuberculosis. Data were analyzed by ANOVA. *P < 0.05; ***P < 0.001
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Fig1: Serum IgG immune response in mice inoculated with T1 C. pseudotuberculosis strain, as evaluated by ELISA. Graph represents means of Optical Density (OD) values found for each group (n = 5 animals for group). Results are representative of the mean values obtained from two experiments. a. BALB/c mice were inoculated with increasing dosages: 5x105, 1x106, 5x106 and 1x107 CFU. Blood was collected 120 days after inoculation. Data were analyzed by ANOVA and Tukey post-hoc tests; *, †, ‡ and § indicate pairs with statistically significant differences. b. IgG subclass (IgG1, IgG2a, IgG2b and IgG3) production throughout the course of the experiment: control (before infection), 7, 30, 60, and 120 days after infection. Mice were inoculated with 107 CFU of T1 strain of C. pseudotuberculosis. Data were analyzed by ANOVA. *P < 0.05; ***P < 0.001

Mentions: To determine the optimal inoculation dosage, four different infection dosages (5x105, 1x106, 5x106 and 1x107 CFU) of the T1 C. pseudotuberculosis strain were tested in BALB/c mice. ELISA results showed higher IgG levels in mice infected with the two higher dosages in comparison to the two lower levels tested (P < 0.001) (Fig. 1a). No significant differences in IgG levels were seen between the groups inoculated with 5x106 and 1x107 CFU, nor in the groups inoculated with 5x105 and 1x106 CFU. At 120 days post-infection, none of the animals presented any evidence of lesions characteristic of the disease under clinical examination or necropsy. Because the 1x107 CFU dosage was not observed to induce lesions, this experimental protocol was used to evaluate the production of IgG subclasses and cytokines.Fig. 1


Humoral and cellular immune responses in mice against secreted and somatic antigens from a C orynebacterium pseudotuberculosis attenuated strain: Immune response against a C. pseudotuberculosis strain
Serum IgG immune response in mice inoculated with T1 C. pseudotuberculosis strain, as evaluated by ELISA. Graph represents means of Optical Density (OD) values found for each group (n = 5 animals for group). Results are representative of the mean values obtained from two experiments. a. BALB/c mice were inoculated with increasing dosages: 5x105, 1x106, 5x106 and 1x107 CFU. Blood was collected 120 days after inoculation. Data were analyzed by ANOVA and Tukey post-hoc tests; *, †, ‡ and § indicate pairs with statistically significant differences. b. IgG subclass (IgG1, IgG2a, IgG2b and IgG3) production throughout the course of the experiment: control (before infection), 7, 30, 60, and 120 days after infection. Mice were inoculated with 107 CFU of T1 strain of C. pseudotuberculosis. Data were analyzed by ANOVA. *P < 0.05; ***P < 0.001
© Copyright Policy - OpenAccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC5017044&req=5

Fig1: Serum IgG immune response in mice inoculated with T1 C. pseudotuberculosis strain, as evaluated by ELISA. Graph represents means of Optical Density (OD) values found for each group (n = 5 animals for group). Results are representative of the mean values obtained from two experiments. a. BALB/c mice were inoculated with increasing dosages: 5x105, 1x106, 5x106 and 1x107 CFU. Blood was collected 120 days after inoculation. Data were analyzed by ANOVA and Tukey post-hoc tests; *, †, ‡ and § indicate pairs with statistically significant differences. b. IgG subclass (IgG1, IgG2a, IgG2b and IgG3) production throughout the course of the experiment: control (before infection), 7, 30, 60, and 120 days after infection. Mice were inoculated with 107 CFU of T1 strain of C. pseudotuberculosis. Data were analyzed by ANOVA. *P < 0.05; ***P < 0.001
Mentions: To determine the optimal inoculation dosage, four different infection dosages (5x105, 1x106, 5x106 and 1x107 CFU) of the T1 C. pseudotuberculosis strain were tested in BALB/c mice. ELISA results showed higher IgG levels in mice infected with the two higher dosages in comparison to the two lower levels tested (P < 0.001) (Fig. 1a). No significant differences in IgG levels were seen between the groups inoculated with 5x106 and 1x107 CFU, nor in the groups inoculated with 5x105 and 1x106 CFU. At 120 days post-infection, none of the animals presented any evidence of lesions characteristic of the disease under clinical examination or necropsy. Because the 1x107 CFU dosage was not observed to induce lesions, this experimental protocol was used to evaluate the production of IgG subclasses and cytokines.Fig. 1

View Article: PubMed Central - PubMed

ABSTRACT

Background: Corynebacterium pseudotuberculosis is the etiologic agent of caseous lymphadenitis (CL), a chronic disease that affects goats and sheep. CL is characterized by the formation of granulomas in lymph nodes and other organs, such as the lungs and liver. Current knowledge of CL pathogenesis indicates that the induction of humoral and cellular immune responses are fundamental to disease control. The aim of this study was to evaluate the humoral and cellular immune responses in BALB/c mice inoculated with a C. pseudotuberculosis strain isolated in the state of Bahia, Brazil.

Results: The lymphocyte proliferation and in vitro production of IFN-&gamma;, IL-4, IL-10, IL-12 and nitric oxide by spleen cells stimulated with secreted and somatic antigens from the studied strain were evaluated. IgG subclasses were also analyzed. Results showed a significant increase of Th1-profile cytokines after 60&nbsp;days post-inoculation, as well as an important humoral response, represented by high levels of IgG2a and IgG1 against C. pseudotuberculosis.

Conclusion: The T1 strain of C. pseudotuberculosis was shown to induce humoral and cellular immune responses in BALB/c mice, but, even at a dosage of 1x107 CFU, no signs of the disease were observed.

No MeSH data available.


Related in: MedlinePlus