Oral vaccination with Liporale™-BCG induces CD4⁺ T cell cytokine production in the lung.

<p>Lymphocytes from the lungs of naïve, Liporale™-BCG vaccinated (BCG oral) or subcutaneous vaccinated (BCG s.c.) mice were stimulated for 6 hours <i>in vitro</i> in the presence of Brefeldin A and monensin then analyzed by flow cytometry. (A) Representative plots show CD4⁺ T cells from the lungs of naïve or BCG vaccinated mice expressing IFNγ, TNFα or IL-2. (B) Bar graphs show the percentage of CD4⁺ T cells from the lungs of naïve or BCG vaccinated mice expressing cytokines at 4, 8 or 30 weeks post immunization. Results are displayed as mean + SEM of n = 5 for each group, significance expressed relative to naïve: *p<0.05, **p<0.01, ***p<0.001 (one way ANOVA with Tukey post test). Eight and 30 weeks results are representative of 2 independent experiments.</p

Oral vaccination with Liporale™-BCG increases the number of Ag85B-specific CD4⁺ T cells in the spleen.

<p>Lymphocytes from the spleens of naïve, Liporale™-BCG vaccinated (BCG oral) or subcutaneously vaccinated (BCG s.c.) mice were stained with an Ag85B/MHCII tetramer and enriched for tetramer positive cells by magnetic bead isolation. (A) Representative flow cytometry plots show Ag85B-specific CD4⁺ T cells in the spleens of naïve or BCG vaccinated mice at 4, 8 and 30 weeks post immunization. (B) Bar graphs show the number of Ag85B-specific CD4⁺ T cells in the spleens of naïve or BCG vaccinated mice at 4, 8 and 30 weeks post vaccination. Results are displayed as mean +SEM of n = 5 for each group, significance expressed relative to naïve: *p<0.05, **p<0.01, ***p<0.001 (one way ANOVA with Tukey post test). The 8 and 30 weeks results are representative of 2 independent experiments.</p

Oral vaccination with Liporale™ BCG induces effector and central memory Ag85B-specific CD4⁺ T cells in the spleen.

<p>Lymphocytes from the spleens of naïve, Liporale™-BCG vaccinated (BCG oral) or subcutaneously vaccinated (BCG s.c.) mice were stained with an Ag85B/MHCII tetramer and enriched for tetramer positive cells by magnetic bead isolation. (A) Representative flow cytometry density plots showing CD62L and CD44 expression on total CD4⁺ T cells from spleens of naïve mice, or Ag85b-specific CD4⁺ T cells from the spleens of BCG vaccinated mice. (B) Bar graphs showing the proportion of naïve (CD62L^hi, CD44^lo), T_EFF/T_EM (CD62L^lo, CD44^hi) or T_CM (CD62L^hi, CD44^hi) CD4⁺ T lymphocytes of total CD4⁺ T cells from naïve mice or Ag85B-specific CD4⁺ T cells from the spleens of BCG vaccinated mice at 4, 8 and 30 weeks post vaccination. Results are displayed as mean + SEM of n = 5 for each group: *p<0.05, **p<0.01, ***p<0.001 (Mann-Whitney test). Eight and 30 weeks results are representative of 2 independent experiments.</p

Oral vaccination with Liporale™-BCG induces long-lived CD4⁺ effector T cells in the lung.

<p>Lymphocytes from the lungs of naïve, Liporale™-BCG vaccinated (BCG oral) or subcutaneous vaccinated (BCG s.c.) mice were analyzed by flow cytometry. (A) Representative flow cytometry plots show the gating strategy used to identify CD4⁺ T cells. (B) Bar graphs show the proportion of naïve (CD62L^hi, CD44^lo), T_EFF/T_EM (CD62L^lo, CD44^hi) or T_CM (CD62L^hi, CD44^hi) CD4⁺ T lymphocytes of total CD4⁺ T cells from the lungs of naïve or BCG vaccinated mice at 4, 8 and 30 weeks post vaccination. Results are displayed as mean + SEM of n = 5 for each group, significance expressed relative to naïve: *p<0.05, **p<0.01, ***p<0.001 (one way ANOVA with Tukey post test). Eight and 30 weeks results are representative of 2 independent experiments.</p

image_2_Langerin+ CD8α+ Dendritic Cells Drive Early CD8+ T Cell Activation and IL-12 Production During Systemic Bacterial Infection.TIF

<p>Bloodstream infections induce considerable morbidity, high mortality, and represent a significant burden of cost in health care; however, our understanding of the immune response to bacteremia is incomplete. Langerin⁺ CD8α⁺ dendritic cells (DCs), residing in the marginal zone of the murine spleen, have the capacity to cross-prime CD8⁺ T cells and produce IL-12, both of which are important components of antimicrobial immunity. Accordingly, we hypothesized that this DC subset may be a key promoter of adaptive immune responses to blood-borne bacterial infections. Utilizing mice that express the diphtheria toxin receptor under control of the langerin promoter, we investigated the impact of depleting langerin⁺ CD8α⁺ DCs in a murine model of intravenous infection with Mycobacterium bovis bacille Calmette–Guerin (BCG). In the absence of langerin⁺ CD8α⁺ DCs, the immune response to blood-borne BCG infection was diminished: bacterial numbers in the spleen increased, serum IL-12p40 decreased, and delayed CD8⁺ T cell activation, proliferation, and IFN-γ production was evident. Our data revealed that langerin⁺ CD8α⁺ DCs play a pivotal role in initiating CD8⁺ T cell responses and IL-12 production in response to bacteremia and may influence the early control of systemic bacterial infections.</p

image_4_Langerin+ CD8α+ Dendritic Cells Drive Early CD8+ T Cell Activation and IL-12 Production During Systemic Bacterial Infection.TIF

<p>Bloodstream infections induce considerable morbidity, high mortality, and represent a significant burden of cost in health care; however, our understanding of the immune response to bacteremia is incomplete. Langerin⁺ CD8α⁺ dendritic cells (DCs), residing in the marginal zone of the murine spleen, have the capacity to cross-prime CD8⁺ T cells and produce IL-12, both of which are important components of antimicrobial immunity. Accordingly, we hypothesized that this DC subset may be a key promoter of adaptive immune responses to blood-borne bacterial infections. Utilizing mice that express the diphtheria toxin receptor under control of the langerin promoter, we investigated the impact of depleting langerin⁺ CD8α⁺ DCs in a murine model of intravenous infection with Mycobacterium bovis bacille Calmette–Guerin (BCG). In the absence of langerin⁺ CD8α⁺ DCs, the immune response to blood-borne BCG infection was diminished: bacterial numbers in the spleen increased, serum IL-12p40 decreased, and delayed CD8⁺ T cell activation, proliferation, and IFN-γ production was evident. Our data revealed that langerin⁺ CD8α⁺ DCs play a pivotal role in initiating CD8⁺ T cell responses and IL-12 production in response to bacteremia and may influence the early control of systemic bacterial infections.</p

image_3_Langerin+ CD8α+ Dendritic Cells Drive Early CD8+ T Cell Activation and IL-12 Production During Systemic Bacterial Infection.TIF

<p>Bloodstream infections induce considerable morbidity, high mortality, and represent a significant burden of cost in health care; however, our understanding of the immune response to bacteremia is incomplete. Langerin⁺ CD8α⁺ dendritic cells (DCs), residing in the marginal zone of the murine spleen, have the capacity to cross-prime CD8⁺ T cells and produce IL-12, both of which are important components of antimicrobial immunity. Accordingly, we hypothesized that this DC subset may be a key promoter of adaptive immune responses to blood-borne bacterial infections. Utilizing mice that express the diphtheria toxin receptor under control of the langerin promoter, we investigated the impact of depleting langerin⁺ CD8α⁺ DCs in a murine model of intravenous infection with Mycobacterium bovis bacille Calmette–Guerin (BCG). In the absence of langerin⁺ CD8α⁺ DCs, the immune response to blood-borne BCG infection was diminished: bacterial numbers in the spleen increased, serum IL-12p40 decreased, and delayed CD8⁺ T cell activation, proliferation, and IFN-γ production was evident. Our data revealed that langerin⁺ CD8α⁺ DCs play a pivotal role in initiating CD8⁺ T cell responses and IL-12 production in response to bacteremia and may influence the early control of systemic bacterial infections.</p

image_1_Langerin+ CD8α+ Dendritic Cells Drive Early CD8+ T Cell Activation and IL-12 Production During Systemic Bacterial Infection.TIF

<p>Bloodstream infections induce considerable morbidity, high mortality, and represent a significant burden of cost in health care; however, our understanding of the immune response to bacteremia is incomplete. Langerin⁺ CD8α⁺ dendritic cells (DCs), residing in the marginal zone of the murine spleen, have the capacity to cross-prime CD8⁺ T cells and produce IL-12, both of which are important components of antimicrobial immunity. Accordingly, we hypothesized that this DC subset may be a key promoter of adaptive immune responses to blood-borne bacterial infections. Utilizing mice that express the diphtheria toxin receptor under control of the langerin promoter, we investigated the impact of depleting langerin⁺ CD8α⁺ DCs in a murine model of intravenous infection with Mycobacterium bovis bacille Calmette–Guerin (BCG). In the absence of langerin⁺ CD8α⁺ DCs, the immune response to blood-borne BCG infection was diminished: bacterial numbers in the spleen increased, serum IL-12p40 decreased, and delayed CD8⁺ T cell activation, proliferation, and IFN-γ production was evident. Our data revealed that langerin⁺ CD8α⁺ DCs play a pivotal role in initiating CD8⁺ T cell responses and IL-12 production in response to bacteremia and may influence the early control of systemic bacterial infections.</p