EphB6-null mutation results in compromised T cell function
Hongyu Luo, … , Johanne Tremblay, Jiangping Wu
Hongyu Luo, … , Johanne Tremblay, Jiangping Wu
Published December 15, 2004
Citation Information: J Clin Invest. 2004;114(12):1762-1773. https://doi.org/10.1172/JCI21846.
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Article Immunology

EphB6-null mutation results in compromised T cell function

Abstract

So far, there is very limited knowledge about the role of Eph kinases, the largest family of receptor tyrosine kinases, in the immune system. Here, using EphB6–/– mice, we demonstrated that in vitro and in vivo T cell responses such as lymphokine secretion, proliferation, and the development of delayed-type skin hypersensitivity and experimental autoimmune encephalitis in EphB6–/– mice were compromised. On the other hand, humoral immune responses, such as serum levels of different Ig isotypes and IgG response to tetanus toxoid, were normal in these mice. Mechanistically, we showed that EphB6 migrated to the aggregated TCRs and rafts after TCR activation. Further downstream, in the absence of EphB6, ZAP-70 activation, LAT phosphorylation, the association of PLCγ1 with SLP-76, and p44/42 MAPK activation were diminished. Thus, we have shown that EphB6 is pivotal in T cell function.

Authors

Hongyu Luo, Guang Yu, Johanne Tremblay, Jiangping Wu

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Figure 7

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Intracellular signaling events downstream of EphB6. Bar graphs show the ...
Intracellular signaling events downstream of EphB6. Bar graphs show the density ratios of phosphorylated molecules versus total protein (as loading controls) of the molecule. (A) EphB6 was required for optimal LAT phosphorylation. EphB6+/+ or EphB6–/– thymocytes were cross-linked with anti-CD3 and anti-CD4 mAbs for 0–5 minutes, as indicated. The cell lysates were immunoblotted (Blot) with Ab against phosphorylated LAT (p-LAT) first (upper panel); the membrane was stripped and reblotted with Ab against LAT (lower panel). (B) EphB6 was required for optimal ZAP-70 phosphorylation. EphB6+/+ or EphB6–/– thymocytes were cross-linked with anti-CD3 and anti-CD4 mAbs for 0 minutes (resting) or 1 minute (activated). The cell lysates were immunoblotted (Blot) with Ab against phosphorylated ZAP-70 (p-ZAP-70) first (upper panel); the membrane was stripped and reblotted with Ab against ZAP-70 (lower panel). (C) EphB6 was not necessary for ZAP-70 membrane translocation. EphB6+/+ or EphB6–/– thymocytes were cross-linked with anti-CD3 and anti-CD4 for 0 minutes (resting) or 20 minutes (activated). The whole-cell lysates, cytosolic protein, and membrane protein, as indicated, were immunoblotted with Ab against ZAP-70. (D) EphB6 augmented binding of SLP-76 with PLCγ1 after TCR activation. EphB6+/+ or EphB6–/– thymocytes were cross-linked with anti-CD3 and anti-CD4 mAbs for 2 minutes. The lysates were immunoprecipitated (IP) with anti-PLCγ1 and blotted with anti–SLP-76 (upper panel). The same membrane was stripped and blotted again with anti-PLCγ1 (lower panel). (E) EphB6 was required for optimal Erk1/2 activation. EphB6+/+ or EphB6–/– thymocytes were cross-linked with anti-CD3 and anti-CD4 mAbs for 0–5 minutes, as indicated. The cell lysates were immunoblotted with Ab against phosphorylated Erk1/2 first (p-Erk1/2, upper panel); the same membrane was stripped and reblotted with Ab against Erk1/2 (lower panel).