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Human placental cytotrophoblasts attract monocytes and CD56(bright) natural killer cells via the actions of monocyte inflammatory protein 1alpha.

Drake PM, Gunn MD, Charo IF, Tsou CL, Zhou Y, Huang L, Fisher SJ - J. Exp. Med. (2001)

Bottom Line: This was confirmed by localizing the corresponding mRNA and protein, both in vitro and in vivo.Immunodepletion of MIP-1alpha from cytotrophoblast conditioned medium showed that this chemokine was responsible for a significant portion of the induced monocyte and CD56(bright) NK cell chemotaxis.These data suggest the specific conclusion that cytotrophoblasts can attract monocytes and CD56(bright) NK cells by producing MIP-1alpha and the more general hypothesis that these cells may organize and act on leukocytes at the maternal-fetal interface.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biophysics, University of California at San Francisco, CA 94143, USA.

ABSTRACT
During human pregnancy, the specialized epithelial cells of the placenta (cytotrophoblasts) come into direct contact with immune cells in several locations. In the fetal compartment of the placenta, cytotrophoblast stem cells lie adjacent to macrophages (Hofbauer cells) that reside within the chorionic villus stroma. At sites of placental attachment to the mother, invasive cytotrophoblasts encounter specialized maternal natural killer (NK) cells (CD56(bright)), macrophages, and T cells that accumulate within the uterine wall during pregnancy. Here we tested the hypothesis that fetal cytotrophoblasts can direct the migration of these maternal immune cells. First, we assayed the chemotactic activity of cytotrophoblast conditioned medium samples, using human peripheral blood mononuclear cells as targets. The placental samples preferentially attracted NK cells (both CD56(dim) and CD56(bright)), monocytes, and T cells, suggesting that our hypothesis was correct. A screen to identify chemokine activity through the induction of a Ca(2)+ flux in cells transfected with individual chemokine receptors suggested that cytotrophoblasts secreted monocyte inflammatory protein (MIP)-1alpha. This was confirmed by localizing the corresponding mRNA and protein, both in vitro and in vivo. MIP-1alpha protein in conditioned medium was further characterized by immunoblotting and enzyme-linked immunosorbent assay. Immunodepletion of MIP-1alpha from cytotrophoblast conditioned medium showed that this chemokine was responsible for a significant portion of the induced monocyte and CD56(bright) NK cell chemotaxis. These data suggest the specific conclusion that cytotrophoblasts can attract monocytes and CD56(bright) NK cells by producing MIP-1alpha and the more general hypothesis that these cells may organize and act on leukocytes at the maternal-fetal interface.

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The effects of recombinant MIP-1α on PBMC chemotaxis. (A–C) Results of a representative experiment. (A) Monocyte chemotaxis toward a dilution series of recombinant MIP-1α (rMIP-1α) peaked at a concentration of 10 ng/ml. Addition of a neutralizing anti–MIP-1α IgG (NIgG) returned migration to baseline levels, and a control IgG antibody (CIgG) added at the same concentration had no effect. (B) CD56bright and (C) CD56dim NK cells also responded to recombinant MIP-1α, but their migration did not peak within the range of concentrations tested. Addition of anti–MIP-1α reduced NK cell migration to baseline.
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Figure 8: The effects of recombinant MIP-1α on PBMC chemotaxis. (A–C) Results of a representative experiment. (A) Monocyte chemotaxis toward a dilution series of recombinant MIP-1α (rMIP-1α) peaked at a concentration of 10 ng/ml. Addition of a neutralizing anti–MIP-1α IgG (NIgG) returned migration to baseline levels, and a control IgG antibody (CIgG) added at the same concentration had no effect. (B) CD56bright and (C) CD56dim NK cells also responded to recombinant MIP-1α, but their migration did not peak within the range of concentrations tested. Addition of anti–MIP-1α reduced NK cell migration to baseline.

Mentions: Having shown that cytotrophoblasts produce MIP-1α, we assessed the contribution of this chemokine to the CM activity originally observed: induction of monocyte, NK cell, and T cell chemotaxis. First, we performed control experiments to characterize the chemotactic activity of MIP-1α in our system, using recombinant chemokine with unstimulated PBMCs as targets (Fig. 8). A range of concentrations that encompassed those found in cytotrophoblast CM was tested. This control system also allowed us to demonstrate the efficacy of the function-perturbing anti–MIP-1α antibody that was used in subsequent experiments.


Human placental cytotrophoblasts attract monocytes and CD56(bright) natural killer cells via the actions of monocyte inflammatory protein 1alpha.

Drake PM, Gunn MD, Charo IF, Tsou CL, Zhou Y, Huang L, Fisher SJ - J. Exp. Med. (2001)

The effects of recombinant MIP-1α on PBMC chemotaxis. (A–C) Results of a representative experiment. (A) Monocyte chemotaxis toward a dilution series of recombinant MIP-1α (rMIP-1α) peaked at a concentration of 10 ng/ml. Addition of a neutralizing anti–MIP-1α IgG (NIgG) returned migration to baseline levels, and a control IgG antibody (CIgG) added at the same concentration had no effect. (B) CD56bright and (C) CD56dim NK cells also responded to recombinant MIP-1α, but their migration did not peak within the range of concentrations tested. Addition of anti–MIP-1α reduced NK cell migration to baseline.
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Related In: Results  -  Collection

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Figure 8: The effects of recombinant MIP-1α on PBMC chemotaxis. (A–C) Results of a representative experiment. (A) Monocyte chemotaxis toward a dilution series of recombinant MIP-1α (rMIP-1α) peaked at a concentration of 10 ng/ml. Addition of a neutralizing anti–MIP-1α IgG (NIgG) returned migration to baseline levels, and a control IgG antibody (CIgG) added at the same concentration had no effect. (B) CD56bright and (C) CD56dim NK cells also responded to recombinant MIP-1α, but their migration did not peak within the range of concentrations tested. Addition of anti–MIP-1α reduced NK cell migration to baseline.
Mentions: Having shown that cytotrophoblasts produce MIP-1α, we assessed the contribution of this chemokine to the CM activity originally observed: induction of monocyte, NK cell, and T cell chemotaxis. First, we performed control experiments to characterize the chemotactic activity of MIP-1α in our system, using recombinant chemokine with unstimulated PBMCs as targets (Fig. 8). A range of concentrations that encompassed those found in cytotrophoblast CM was tested. This control system also allowed us to demonstrate the efficacy of the function-perturbing anti–MIP-1α antibody that was used in subsequent experiments.

Bottom Line: This was confirmed by localizing the corresponding mRNA and protein, both in vitro and in vivo.Immunodepletion of MIP-1alpha from cytotrophoblast conditioned medium showed that this chemokine was responsible for a significant portion of the induced monocyte and CD56(bright) NK cell chemotaxis.These data suggest the specific conclusion that cytotrophoblasts can attract monocytes and CD56(bright) NK cells by producing MIP-1alpha and the more general hypothesis that these cells may organize and act on leukocytes at the maternal-fetal interface.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry and Biophysics, University of California at San Francisco, CA 94143, USA.

ABSTRACT
During human pregnancy, the specialized epithelial cells of the placenta (cytotrophoblasts) come into direct contact with immune cells in several locations. In the fetal compartment of the placenta, cytotrophoblast stem cells lie adjacent to macrophages (Hofbauer cells) that reside within the chorionic villus stroma. At sites of placental attachment to the mother, invasive cytotrophoblasts encounter specialized maternal natural killer (NK) cells (CD56(bright)), macrophages, and T cells that accumulate within the uterine wall during pregnancy. Here we tested the hypothesis that fetal cytotrophoblasts can direct the migration of these maternal immune cells. First, we assayed the chemotactic activity of cytotrophoblast conditioned medium samples, using human peripheral blood mononuclear cells as targets. The placental samples preferentially attracted NK cells (both CD56(dim) and CD56(bright)), monocytes, and T cells, suggesting that our hypothesis was correct. A screen to identify chemokine activity through the induction of a Ca(2)+ flux in cells transfected with individual chemokine receptors suggested that cytotrophoblasts secreted monocyte inflammatory protein (MIP)-1alpha. This was confirmed by localizing the corresponding mRNA and protein, both in vitro and in vivo. MIP-1alpha protein in conditioned medium was further characterized by immunoblotting and enzyme-linked immunosorbent assay. Immunodepletion of MIP-1alpha from cytotrophoblast conditioned medium showed that this chemokine was responsible for a significant portion of the induced monocyte and CD56(bright) NK cell chemotaxis. These data suggest the specific conclusion that cytotrophoblasts can attract monocytes and CD56(bright) NK cells by producing MIP-1alpha and the more general hypothesis that these cells may organize and act on leukocytes at the maternal-fetal interface.

Show MeSH