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Expression of leukosialin (CD43) defines a major intrahepatic T cell subset associated with protective responses in visceral leishmaniasis.

Nico D, Maran N, Santos L, Ramos-Junior ES, Mantuano NR, Coutinho JL, Vale AM, Freire-de-Lima CG, Todeschini A, Rodrigues JC, Palatnik-de-Sousa CB, Morrot A - Parasit Vectors (2015)

Bottom Line: IFN-γ-producing T cells are involved in protection against the disease.We further showed that expression of CD43 defines a major intrahepatic CD4⁺ and CD8⁺ T cell subsets with pro-inflammatory phenotypes and leads to increased levels of IFN-γ secretion by activated splenocytes.Our findings point to a role of CD43 in the development of host resistance to visceral leishmaniasis.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), CCS - Sala D1-035, Av. Carlos Chagas Filho, 373 - Cidade Universitária, CEP 21.941-902, Ilha do Fundão, Rio de Janeiro, RJ, Brazil. morrot@micro.ufrj.br.

ABSTRACT

Background: Leishmaniasis is a neglected vector-borne tropical disease caused by Leishmania protozoa that are transmitted to mammalian hosts by infected sand flies. Infection is associated with distinct clinical manifestations that include cutaneous, mucocutaneous and visceral lesions. Visceral leishmaniasis (VL) is the most severe form of the disease and is considered second in terms of mortality and fourth in terms of morbidity among tropical diseases. IFN-γ-producing T cells are involved in protection against the disease.

Methods: CD43⁺/⁺ and CD43⁻/⁻ mice on a C57BL/6 background were intravenously injected with 5 × 10 ⁷ amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection the clinical signs of disease were examined; the splenocytes were isolated and assayed for cytokine production; and the livers were removed for phenotypic analysis of T cell subsets by flow cytometry.

Results: We report that mice lacking CD43 display increased susceptibility to infection by Leishmania (L.) infantum chagasi, with higher parasite burdens than wild-type mice. The increased susceptibility of CD43⁻/⁻ mice were associated with a weakened delayed hypersensitivity response and reduced levels of IgG2a antibodies to leishmania antigens. We further showed that expression of CD43 defines a major intrahepatic CD4⁺ and CD8⁺ T cell subsets with pro-inflammatory phenotypes and leads to increased levels of IFN-γ secretion by activated splenocytes.

Conclusions: Our findings point to a role of CD43 in the development of host resistance to visceral leishmaniasis.

No MeSH data available.


Related in: MedlinePlus

Splenocytes from CD43-deficient mice produce low levels of IFN-γ. CD43+/+ and CD43−/− mice were infected intravenously with 5 × 107 amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection splenocytes were isolated and assayed for cytokine production. After 3 days of in vitro culture with freeze and thawed lysates of Leishmania (L.) infantum chagasi promastigotes, as described in the Methods sections, splenocyte supernatants were harvested for determination of (A) IFN-γ, (B) TGF-β and (C) IL-10 by ELISA. The y-axis represents the levels of cytokines, detected by specific ELISA assays, expressed in ng/ml. Asterisks represent statistical significance between groups (p < 0.05). All experiments were repeated at least 3 times.
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Fig3: Splenocytes from CD43-deficient mice produce low levels of IFN-γ. CD43+/+ and CD43−/− mice were infected intravenously with 5 × 107 amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection splenocytes were isolated and assayed for cytokine production. After 3 days of in vitro culture with freeze and thawed lysates of Leishmania (L.) infantum chagasi promastigotes, as described in the Methods sections, splenocyte supernatants were harvested for determination of (A) IFN-γ, (B) TGF-β and (C) IL-10 by ELISA. The y-axis represents the levels of cytokines, detected by specific ELISA assays, expressed in ng/ml. Asterisks represent statistical significance between groups (p < 0.05). All experiments were repeated at least 3 times.

Mentions: A major factor that is believed to contribute to healing in leishmaniasis is the development of a strong IFN-γ response, which induces IgG2a production [23]. We therefore compared the cytokine responses to infection with Leishmania (L.) infantum chagasi parasites by analyzing the cytokines in supernatants of splenocytes isolated from infected wild-type and knockout mice stimulated with whole parasite antigens for 3 days. Splenocytes obtained from infected wild-type mice at 30 DPI when stimulated with parasite antigen mounted a typical protective pro-inflammatory response characterized by high levels of IFN-γ and low levels of TGF-β (Figure 3A, B). In contrast, the splenocytes from infected CD43−/− mice produced reduced levels of IFN-γ and high levels of TGF-β upon stimulation with parasite antigens (Figure 3A, B). This clearly demonstrates that CD43-deficient mice have impaired immune response generation after infection with Leishmania (L.) infantum chagasi. In fact, splenocytes from CD43−/− mice spontaneously secreted TGF-β as seen in the unstimulated controls (Figure 3B) and did not decrease the production of IL-10 upon stimulation with parasite antigens as compared to wild-type cells (Figure 2C). We did not detect significant levels of TNF-α in the culture supernatants (Data not shown).Figure 3


Expression of leukosialin (CD43) defines a major intrahepatic T cell subset associated with protective responses in visceral leishmaniasis.

Nico D, Maran N, Santos L, Ramos-Junior ES, Mantuano NR, Coutinho JL, Vale AM, Freire-de-Lima CG, Todeschini A, Rodrigues JC, Palatnik-de-Sousa CB, Morrot A - Parasit Vectors (2015)

Splenocytes from CD43-deficient mice produce low levels of IFN-γ. CD43+/+ and CD43−/− mice were infected intravenously with 5 × 107 amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection splenocytes were isolated and assayed for cytokine production. After 3 days of in vitro culture with freeze and thawed lysates of Leishmania (L.) infantum chagasi promastigotes, as described in the Methods sections, splenocyte supernatants were harvested for determination of (A) IFN-γ, (B) TGF-β and (C) IL-10 by ELISA. The y-axis represents the levels of cytokines, detected by specific ELISA assays, expressed in ng/ml. Asterisks represent statistical significance between groups (p < 0.05). All experiments were repeated at least 3 times.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC4340829&req=5

Fig3: Splenocytes from CD43-deficient mice produce low levels of IFN-γ. CD43+/+ and CD43−/− mice were infected intravenously with 5 × 107 amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection splenocytes were isolated and assayed for cytokine production. After 3 days of in vitro culture with freeze and thawed lysates of Leishmania (L.) infantum chagasi promastigotes, as described in the Methods sections, splenocyte supernatants were harvested for determination of (A) IFN-γ, (B) TGF-β and (C) IL-10 by ELISA. The y-axis represents the levels of cytokines, detected by specific ELISA assays, expressed in ng/ml. Asterisks represent statistical significance between groups (p < 0.05). All experiments were repeated at least 3 times.
Mentions: A major factor that is believed to contribute to healing in leishmaniasis is the development of a strong IFN-γ response, which induces IgG2a production [23]. We therefore compared the cytokine responses to infection with Leishmania (L.) infantum chagasi parasites by analyzing the cytokines in supernatants of splenocytes isolated from infected wild-type and knockout mice stimulated with whole parasite antigens for 3 days. Splenocytes obtained from infected wild-type mice at 30 DPI when stimulated with parasite antigen mounted a typical protective pro-inflammatory response characterized by high levels of IFN-γ and low levels of TGF-β (Figure 3A, B). In contrast, the splenocytes from infected CD43−/− mice produced reduced levels of IFN-γ and high levels of TGF-β upon stimulation with parasite antigens (Figure 3A, B). This clearly demonstrates that CD43-deficient mice have impaired immune response generation after infection with Leishmania (L.) infantum chagasi. In fact, splenocytes from CD43−/− mice spontaneously secreted TGF-β as seen in the unstimulated controls (Figure 3B) and did not decrease the production of IL-10 upon stimulation with parasite antigens as compared to wild-type cells (Figure 2C). We did not detect significant levels of TNF-α in the culture supernatants (Data not shown).Figure 3

Bottom Line: IFN-γ-producing T cells are involved in protection against the disease.We further showed that expression of CD43 defines a major intrahepatic CD4⁺ and CD8⁺ T cell subsets with pro-inflammatory phenotypes and leads to increased levels of IFN-γ secretion by activated splenocytes.Our findings point to a role of CD43 in the development of host resistance to visceral leishmaniasis.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Imunologia, Instituto de Microbiologia, Universidade Federal do Rio de Janeiro (UFRJ), CCS - Sala D1-035, Av. Carlos Chagas Filho, 373 - Cidade Universitária, CEP 21.941-902, Ilha do Fundão, Rio de Janeiro, RJ, Brazil. morrot@micro.ufrj.br.

ABSTRACT

Background: Leishmaniasis is a neglected vector-borne tropical disease caused by Leishmania protozoa that are transmitted to mammalian hosts by infected sand flies. Infection is associated with distinct clinical manifestations that include cutaneous, mucocutaneous and visceral lesions. Visceral leishmaniasis (VL) is the most severe form of the disease and is considered second in terms of mortality and fourth in terms of morbidity among tropical diseases. IFN-γ-producing T cells are involved in protection against the disease.

Methods: CD43⁺/⁺ and CD43⁻/⁻ mice on a C57BL/6 background were intravenously injected with 5 × 10 ⁷ amastigotes of Leishmania (L.) infantum chagasi, and 30 days after infection the clinical signs of disease were examined; the splenocytes were isolated and assayed for cytokine production; and the livers were removed for phenotypic analysis of T cell subsets by flow cytometry.

Results: We report that mice lacking CD43 display increased susceptibility to infection by Leishmania (L.) infantum chagasi, with higher parasite burdens than wild-type mice. The increased susceptibility of CD43⁻/⁻ mice were associated with a weakened delayed hypersensitivity response and reduced levels of IgG2a antibodies to leishmania antigens. We further showed that expression of CD43 defines a major intrahepatic CD4⁺ and CD8⁺ T cell subsets with pro-inflammatory phenotypes and leads to increased levels of IFN-γ secretion by activated splenocytes.

Conclusions: Our findings point to a role of CD43 in the development of host resistance to visceral leishmaniasis.

No MeSH data available.


Related in: MedlinePlus