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Low dose Leishmania major promotes a transient T helper cell type 2 response that is down-regulated by interferon gamma-producing CD8+ T cells.

Uzonna JE, Joyce KL, Scott P - J. Exp. Med. (2004)

Bottom Line: An unresolved issue in the field of T helper (Th) cell development relates to the findings that low doses of antigen promote Th2 cell development in vitro, whereas several classic in vivo studies suggest the opposite.In the absence of CD8+ T cells, the Th2 response was maintained.Thus, the discrepant results seen between in vivo and in vitro studies on the effects of antigen dose on Th cell differentiation may depend upon whether CD8+ T cells participate in the immune response.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia 19104, USA.

ABSTRACT
An unresolved issue in the field of T helper (Th) cell development relates to the findings that low doses of antigen promote Th2 cell development in vitro, whereas several classic in vivo studies suggest the opposite. Here we resolve this paradox by studying the early immune response in mice after infection with different doses of Leishmania major. We found that low parasite doses induced a Th2 response in C57BL/6 (B6) mice, whereas high doses induced a Th1 response. However, the Th2 response in low dose-infected mice was transient and the animals healed. The appearance of a Th1 response after low dose infection was dependent upon the concomitant activation of interferon gamma-producing CD8+ T cells. In the absence of CD8+ T cells, the Th2 response was maintained. However, either neutralization of interleukin (IL)-4 or administration of IL-12 promoted a Th1 response after low dose infection of CD8-deficient mice, indicating that the required role for CD8+ T cells was limited to modulation of CD4+ T cell responses. Thus, the discrepant results seen between in vivo and in vitro studies on the effects of antigen dose on Th cell differentiation may depend upon whether CD8+ T cells participate in the immune response.

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Parasite dose influences the development of CD4+ T cell responses in vivo. (A) Antigen-specific proliferation by CD4+ T cells is diminished in low dose–infected mice. B6 mice were infected intradermally with a low (103) or high (106) dose of L. major. 3 wk after infection, mice were killed and cells isolated from the retromaxillary draining lymph node (dLN) were CFSE labeled, stimulated for 5 d with SLA, and analyzed for proliferation by flow cytometry by gating on live CD4+ cells. (B) Low dose L. major infection induces an early CD4+ Th2 response. Cells from A above were also stained for intracellular IFN-γ and IL-4. (C) Levels of IFN-γ and IL-4 in 72-h culture supernatant fluids of lymph node cells from A above. (D and E) The early low dose–induced Th2 response in B6 mice is transient. B6 mice infected with a low or high dose of L. major were monitored weekly for the development and progression of cutaneous lesion (D). 16 wk after infection and resolution of lesion, mice were killed and cells from the dLN were stimulated with SLA for 72 h. The supernatant fluid was then assayed for IFN-γ and IL-4 by ELISA (E). Representative data from three experiments with similar results are presented.
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fig1: Parasite dose influences the development of CD4+ T cell responses in vivo. (A) Antigen-specific proliferation by CD4+ T cells is diminished in low dose–infected mice. B6 mice were infected intradermally with a low (103) or high (106) dose of L. major. 3 wk after infection, mice were killed and cells isolated from the retromaxillary draining lymph node (dLN) were CFSE labeled, stimulated for 5 d with SLA, and analyzed for proliferation by flow cytometry by gating on live CD4+ cells. (B) Low dose L. major infection induces an early CD4+ Th2 response. Cells from A above were also stained for intracellular IFN-γ and IL-4. (C) Levels of IFN-γ and IL-4 in 72-h culture supernatant fluids of lymph node cells from A above. (D and E) The early low dose–induced Th2 response in B6 mice is transient. B6 mice infected with a low or high dose of L. major were monitored weekly for the development and progression of cutaneous lesion (D). 16 wk after infection and resolution of lesion, mice were killed and cells from the dLN were stimulated with SLA for 72 h. The supernatant fluid was then assayed for IFN-γ and IL-4 by ELISA (E). Representative data from three experiments with similar results are presented.

Mentions: To investigate the influence of parasite dose on the development of CD4+ T cells in vivo, B6 mice were infected with either 103 or 106 L. major intradermally in the ear. After 3 wk, cells from the draining lymph nodes of infected mice were CFSE labeled to monitor proliferation and stimulated with SLA. CD4+ T cells from mice infected with a high dose of parasites exhibited substantial antigen-specific proliferation (Fig. 1 A). In addition, intracellular cytokine staining indicated that a large percentage of the CD4+ T cells produced IFN-γ, whereas few cells produced IL-4 (Fig. 1 B). In contrast, cells from low dose–infected mice proliferated less well, and a smaller percentage of cells made IFN-γ. However, a significantly higher percentage of cells from low dose–infected mice made IL-4. This pattern of response was also observed when cytokine production was measured by ELISA. Cells from low dose–infected mice produced more IL-4 and less IFN-γ, whereas those from high dose–infected mice produced no IL-4, but high levels of IFN-γ (Fig. 1 C). Thus, at this early time point, the CD4+ T cell response in B6 mice infected with low doses of L. major is strongly biased toward a Th2 response. Nevertheless, as reported previously (13, 15), low dose infections were associated with healing and effective parasite control several weeks after infection (Fig. 1 D and unpublished data). Furthermore, when the immune response was assessed in the healed mice, both low and high dose–infected mice exhibited an enhanced IFN-γ response, indicating that the dominant CD4+ Th2 response seen in low dose–infected mice was transient (Fig. 1 E).


Low dose Leishmania major promotes a transient T helper cell type 2 response that is down-regulated by interferon gamma-producing CD8+ T cells.

Uzonna JE, Joyce KL, Scott P - J. Exp. Med. (2004)

Parasite dose influences the development of CD4+ T cell responses in vivo. (A) Antigen-specific proliferation by CD4+ T cells is diminished in low dose–infected mice. B6 mice were infected intradermally with a low (103) or high (106) dose of L. major. 3 wk after infection, mice were killed and cells isolated from the retromaxillary draining lymph node (dLN) were CFSE labeled, stimulated for 5 d with SLA, and analyzed for proliferation by flow cytometry by gating on live CD4+ cells. (B) Low dose L. major infection induces an early CD4+ Th2 response. Cells from A above were also stained for intracellular IFN-γ and IL-4. (C) Levels of IFN-γ and IL-4 in 72-h culture supernatant fluids of lymph node cells from A above. (D and E) The early low dose–induced Th2 response in B6 mice is transient. B6 mice infected with a low or high dose of L. major were monitored weekly for the development and progression of cutaneous lesion (D). 16 wk after infection and resolution of lesion, mice were killed and cells from the dLN were stimulated with SLA for 72 h. The supernatant fluid was then assayed for IFN-γ and IL-4 by ELISA (E). Representative data from three experiments with similar results are presented.
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Related In: Results  -  Collection

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getmorefigures.php?uid=PMC2211781&req=5

fig1: Parasite dose influences the development of CD4+ T cell responses in vivo. (A) Antigen-specific proliferation by CD4+ T cells is diminished in low dose–infected mice. B6 mice were infected intradermally with a low (103) or high (106) dose of L. major. 3 wk after infection, mice were killed and cells isolated from the retromaxillary draining lymph node (dLN) were CFSE labeled, stimulated for 5 d with SLA, and analyzed for proliferation by flow cytometry by gating on live CD4+ cells. (B) Low dose L. major infection induces an early CD4+ Th2 response. Cells from A above were also stained for intracellular IFN-γ and IL-4. (C) Levels of IFN-γ and IL-4 in 72-h culture supernatant fluids of lymph node cells from A above. (D and E) The early low dose–induced Th2 response in B6 mice is transient. B6 mice infected with a low or high dose of L. major were monitored weekly for the development and progression of cutaneous lesion (D). 16 wk after infection and resolution of lesion, mice were killed and cells from the dLN were stimulated with SLA for 72 h. The supernatant fluid was then assayed for IFN-γ and IL-4 by ELISA (E). Representative data from three experiments with similar results are presented.
Mentions: To investigate the influence of parasite dose on the development of CD4+ T cells in vivo, B6 mice were infected with either 103 or 106 L. major intradermally in the ear. After 3 wk, cells from the draining lymph nodes of infected mice were CFSE labeled to monitor proliferation and stimulated with SLA. CD4+ T cells from mice infected with a high dose of parasites exhibited substantial antigen-specific proliferation (Fig. 1 A). In addition, intracellular cytokine staining indicated that a large percentage of the CD4+ T cells produced IFN-γ, whereas few cells produced IL-4 (Fig. 1 B). In contrast, cells from low dose–infected mice proliferated less well, and a smaller percentage of cells made IFN-γ. However, a significantly higher percentage of cells from low dose–infected mice made IL-4. This pattern of response was also observed when cytokine production was measured by ELISA. Cells from low dose–infected mice produced more IL-4 and less IFN-γ, whereas those from high dose–infected mice produced no IL-4, but high levels of IFN-γ (Fig. 1 C). Thus, at this early time point, the CD4+ T cell response in B6 mice infected with low doses of L. major is strongly biased toward a Th2 response. Nevertheless, as reported previously (13, 15), low dose infections were associated with healing and effective parasite control several weeks after infection (Fig. 1 D and unpublished data). Furthermore, when the immune response was assessed in the healed mice, both low and high dose–infected mice exhibited an enhanced IFN-γ response, indicating that the dominant CD4+ Th2 response seen in low dose–infected mice was transient (Fig. 1 E).

Bottom Line: An unresolved issue in the field of T helper (Th) cell development relates to the findings that low doses of antigen promote Th2 cell development in vitro, whereas several classic in vivo studies suggest the opposite.In the absence of CD8+ T cells, the Th2 response was maintained.Thus, the discrepant results seen between in vivo and in vitro studies on the effects of antigen dose on Th cell differentiation may depend upon whether CD8+ T cells participate in the immune response.

View Article: PubMed Central - PubMed

Affiliation: Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania, 3800 Spruce Street, Philadelphia 19104, USA.

ABSTRACT
An unresolved issue in the field of T helper (Th) cell development relates to the findings that low doses of antigen promote Th2 cell development in vitro, whereas several classic in vivo studies suggest the opposite. Here we resolve this paradox by studying the early immune response in mice after infection with different doses of Leishmania major. We found that low parasite doses induced a Th2 response in C57BL/6 (B6) mice, whereas high doses induced a Th1 response. However, the Th2 response in low dose-infected mice was transient and the animals healed. The appearance of a Th1 response after low dose infection was dependent upon the concomitant activation of interferon gamma-producing CD8+ T cells. In the absence of CD8+ T cells, the Th2 response was maintained. However, either neutralization of interleukin (IL)-4 or administration of IL-12 promoted a Th1 response after low dose infection of CD8-deficient mice, indicating that the required role for CD8+ T cells was limited to modulation of CD4+ T cell responses. Thus, the discrepant results seen between in vivo and in vitro studies on the effects of antigen dose on Th cell differentiation may depend upon whether CD8+ T cells participate in the immune response.

Show MeSH
Related in: MedlinePlus