Metabolic shift induced by systemic activation of T cells in PD-1-deficient mice perturbs brain monoamines and emotional behavior

Abstract Infection of susceptible mouse strains with Plasmodium berghei ANKA (PbA) is a valuable experimental model of cerebral malaria (CM). Two major pathologic features of CM are the intravascular sequestration of infected erythrocytes and leukocytes inside brain microvessels. We have recently shown that only the CD8+ T-cell subset of these brain-sequestered leukocytes is critical for progression to CM. Chemokine receptor–5 (CCR5) is an important regulator of leukocyte trafficking in the brain in response to fungal and viral infection. Therefore, we investigated whether CCR5 plays a role in the pathogenesis of experimental CM. Approximately 70% to 85% of wild-type and CCR5+/- mice infected with PbA developed CM, whereas only about 20% of PbA-infected CCR5-deficient mice exhibited the characteristic neurologic signs of CM. The brains of wild-type mice with CM showed significant increases in CCR5+ leukocytes, particularly CCR5+ CD8+ T cells, as well as increases in T-helper 1 (Th1) cytokine production. The few PbA-infected CCR5-deficient mice that developed CM exhibited a similar increase in CD8+ T cells. Significant leukocyte accumulation in the brain and Th1 cytokine production did not occur in PbA-infected CCR5-deficient mice that did not develop CM. Moreover, experiments using bone marrow (BM)–chimeric mice showed that a reduced but significant proportion of deficient mice grafted with CCR5+ BM develop CM, indicating that CCR5 expression on a radiation-resistant brain cell population is necessary for CM to occur. Taken together, these results suggest that CCR5 is an important factor in the development of experimental CM.

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Loss of Immunological Tolerance in Gimap5-Deficient Mice Is Associated with Loss of Foxo in CD4+ T Cells

The Journal of Immunology ◽

10.4049/jimmunol.1101206 ◽

2011 ◽

Vol 188 (1) ◽

pp. 146-154 ◽

Cited By ~ 20

Author(s):

H. Ibrahim Aksoylar ◽

Kristin Lampe ◽

Michael J. Barnes ◽

David R. Plas ◽

Kasper Hoebe

Keyword(s):

T Cells ◽

Cd4 T Cells ◽

Immunological Tolerance ◽

Deficient Mice

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A role for CD9 molecules in T cell activation.

Journal of Experimental Medicine ◽

10.1084/jem.184.2.753 ◽

1996 ◽

Vol 184 (2) ◽

pp. 753-758 ◽

Cited By ~ 63

Author(s):

X G Tai ◽

Y Yashiro ◽

R Abe ◽

K Toyooka ◽

C R Wood ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Immune Responses ◽

T Cell Activation ◽

Cell Activation ◽

Expression Cloning ◽

Wild Type ◽

Almost All ◽

Antigen Presenting ◽

Deficient Mice

Costimulation mediated by the CD28 molecule plays an important role in optimal activation of T cells. However, CD28-deficient mice can mount effective T cell-dependent immune responses, suggesting the existence of other costimulatory systems. In a search for other costimulatory molecules on T cells, we have developed a monoclonal antibody (mAb) that can costimulate T cells in the absence of antigen-presenting cells (APC). The molecule recognized by this mAb, 9D3, was found to be expressed on almost all mature T cells and to be a protein of approximately 24 kD molecular mass. By expression cloning, this molecule was identified as CD9, 9D3 (anti-CD9) synergized with suboptimal doses of anti-CD3 mAb in inducing proliferation by virgin T cells. Costimulation was induced by independent ligation of CD3 and CD9, suggesting that colocalization of these two molecules is not required for T cell activation. The costimulation by anti-CD9 was as potent as that by anti-CD28. Moreover, anti-CD9 costimulated in a CD28-independent way because anti-CD9 equally costimulated T cells from the CD28-deficient as well as wild-type mice. Thus, these results indicate that CD9 serves as a molecule on T cells that can deliver a potent CD28-independent costimulatory signal.

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Tissue-specific expression of B7x protects from CD4 T cell–mediated autoimmunity

Journal of Experimental Medicine ◽

10.1084/jem.20100639 ◽

2011 ◽

Vol 208 (8) ◽

pp. 1683-1694 ◽

Cited By ~ 44

Author(s):

Joyce Wei ◽

P’ng Loke ◽

Xingxing Zang ◽

James P. Allison

Keyword(s):

T Cells ◽

Pancreatic Islets ◽

Peripheral Tolerance ◽

Wild Type ◽

Autoimmune Encephalomyelitis ◽

Specific Expression ◽

Tissue Specific ◽

Disease Induction ◽

Deficient Mice ◽

Experimental Autoimmune

B7x, an inhibitory member of the B7/CD28 superfamily, is highly expressed in a broad range of nonhematopoietic organs, suggesting a role in maintaining peripheral tolerance. As endogenous B7x protein is expressed in pancreatic islets, we investigated whether the molecule inhibits diabetogenic responses. Transfer of disease-inducing BDC2.5 T cells into B7x-deficient mice resulted in a more aggressive form of diabetes than in wild-type animals. This exacerbation of disease correlated with higher frequencies of islet-infiltrating Th1 and Th17 cells. Conversely, local B7x overexpression inhibited the development of autoimmunity, as crossing diabetes-susceptible BDC2.5/B6g7 mice to animals overexpressing B7x in pancreatic islets abrogated disease induction. This protection was caused by the inhibition of IFN-γ production by CD4 T cells and not to a skewing or expansion of Th2 or regulatory T cells. The suppressive function of B7x was also supported by observations from another autoimmune model, experimental autoimmune encephalomyelitis, in which B7x-deficient mice developed exacerbated disease in comparison with wild-type animals. Analysis of central nervous system–infiltrating immune cells revealed that the loss of endogenous B7x resulted in expanded Th1 and Th17 responses. Data from these two autoimmune models provide evidence that B7x expression in the periphery acts as an immune checkpoint to prevent tissue-specific autoimmunity.

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