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Cell-mediated and humoral immune responses in pigs following primary and challenge-exposure to Lawsonia intracellularis.

Cordes H, Riber U, Jensen TK, Jungersen G - Vet. Res. (2012)

Bottom Line: A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry.The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes.The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1790 Copenhagen V, Denmark. urib@vet.dtu.dk.

ABSTRACT
To investigate immune responses upon re-infection with Lawsonia intracellularis, local and peripheral humoral and cell-mediated immune responses to primary and challenge inoculations were studied in 22 pigs. Pigs were orally inoculated with virulent L. intracellularis at the age of 5-6 weeks, treated with antibiotics and challenged with a re-inoculation (RE) at the age of 12 weeks. Treatment control (TC) pigs received only the primary inoculation and challenge control (CC) pigs received only the secondary inoculation at 12 weeks of age. Following this regimen, all RE pigs were protected against the re-infection as defined by reduced colonisation and pathology of intestinal mucosa, absence of bacterial shedding and without increase in serum acute phase protein response. In the protected RE pigs, serum IgG responses were variable with both high and low responders. Serum IgA responses were not boosted by the re-inoculation, since identical intestinal IgA responses developed in response to the inoculation in both the susceptible CC pigs and the protected RE pigs. A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry. The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes. The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.

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CD4:CD8 ratios in cell cultures. CD4:CD8 ratios (mean of Ag-culture and PBS-culture) of gated lymphocytes in PBMC cell cultures before challenge (day 48) and after challenge (day 67, 75 and 82). Median ratios (line) and significant differences (*) are shown for CC group and RE group.
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Figure 5: CD4:CD8 ratios in cell cultures. CD4:CD8 ratios (mean of Ag-culture and PBS-culture) of gated lymphocytes in PBMC cell cultures before challenge (day 48) and after challenge (day 67, 75 and 82). Median ratios (line) and significant differences (*) are shown for CC group and RE group.

Mentions: The CD4:CD8 ratios within gated lymphocytes in the PBMC cultures are shown in Figure 5. In response to the inoculation at day 49 a significantly reduced CD4:CD8 ratio was found in the susceptible CC group compared to the protected RE group at day 75 and 82 (p < 0.05 Mann Whitney and unpaired t-test). No significant differences were observed between the CC and RE groups at days 48 and 67.


Cell-mediated and humoral immune responses in pigs following primary and challenge-exposure to Lawsonia intracellularis.

Cordes H, Riber U, Jensen TK, Jungersen G - Vet. Res. (2012)

CD4:CD8 ratios in cell cultures. CD4:CD8 ratios (mean of Ag-culture and PBS-culture) of gated lymphocytes in PBMC cell cultures before challenge (day 48) and after challenge (day 67, 75 and 82). Median ratios (line) and significant differences (*) are shown for CC group and RE group.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC3313852&req=5

Figure 5: CD4:CD8 ratios in cell cultures. CD4:CD8 ratios (mean of Ag-culture and PBS-culture) of gated lymphocytes in PBMC cell cultures before challenge (day 48) and after challenge (day 67, 75 and 82). Median ratios (line) and significant differences (*) are shown for CC group and RE group.
Mentions: The CD4:CD8 ratios within gated lymphocytes in the PBMC cultures are shown in Figure 5. In response to the inoculation at day 49 a significantly reduced CD4:CD8 ratio was found in the susceptible CC group compared to the protected RE group at day 75 and 82 (p < 0.05 Mann Whitney and unpaired t-test). No significant differences were observed between the CC and RE groups at days 48 and 67.

Bottom Line: A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry.The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes.The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.

View Article: PubMed Central - HTML - PubMed

Affiliation: National Veterinary Institute, Technical University of Denmark, Bülowsvej 27, 1790 Copenhagen V, Denmark. urib@vet.dtu.dk.

ABSTRACT
To investigate immune responses upon re-infection with Lawsonia intracellularis, local and peripheral humoral and cell-mediated immune responses to primary and challenge inoculations were studied in 22 pigs. Pigs were orally inoculated with virulent L. intracellularis at the age of 5-6 weeks, treated with antibiotics and challenged with a re-inoculation (RE) at the age of 12 weeks. Treatment control (TC) pigs received only the primary inoculation and challenge control (CC) pigs received only the secondary inoculation at 12 weeks of age. Following this regimen, all RE pigs were protected against the re-infection as defined by reduced colonisation and pathology of intestinal mucosa, absence of bacterial shedding and without increase in serum acute phase protein response. In the protected RE pigs, serum IgG responses were variable with both high and low responders. Serum IgA responses were not boosted by the re-inoculation, since identical intestinal IgA responses developed in response to the inoculation in both the susceptible CC pigs and the protected RE pigs. A memory recall cell-mediated immune response developed in RE pigs which was significantly stronger compared to the primary response in age-matched CC pigs as assessed by whole blood IFN-γ assay and by calculation of IFN-γ integrated median fluorescence intensity (iMFI) after flow cytometry. The major IFN-γ producing cells were identified as CD8+ and CD4+CD8+ double positive lymphocytes. The results indicate that cell-mediated immune responses are likely mediators of protective immunity against L. intracellularis, with CD8+ effector cells and CD4+CD8+ double positive memory T cells as main contributors to the antigen-specific IFN-γ production.

Show MeSH
Related in: MedlinePlus