Engagement of transgenic Ly49A inhibits mouse CD4 cell activation by disrupting T cell receptor, but not CD28, signaling.
Islet specific CD4 cells expressing inhibitory receptors may be a useful therapeutic tool for treating type 1 diabetes (T1D). Engagement of transgenic Ly49A inhibits CD4 cell activation and delays onset of T1D in mice. However, in vitro studies suggest the inhibitory effect of Ly49A is incomplete. Here we report that following simultaneous TCR and Ly49A engagement, phosphorylation of Zap70, Erk1/2 and c-Jun were significantly diminished. Kinetic studies indicated that Ly49A did not simply delay activation but had a long-lasting effect. In contrast, when only costimulatory signals were provided through CD28, Ly49A engagement did not block p38 MapK or Akt phosphorylation. Likewise, expression of the downstream targets Bcl-xl and Baff were unaffected. Together these data suggest that engagement of Ly49A selectively inhibits signals downstream of the TCR but spares those unique to CD28. These results suggest that when considering its use as an immunotherapy, the potency of inhibitory receptors such as Ly49A may be further improved by pairing them with costimulatory blockade.
Department of Medical Microbiology, Southern Illinois University School of Medicine, Springfield, IL 62794, USA.
Jianmei W
JW
Leavenworth
Mary E
ME
Pauza
D000818:Animals; D018106:CD28 Antigens / Q000276:immunology / Q000378:metabolism*; D015496:CD4-Positive T-Lymphocytes / Q000276:immunology / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000276:immunology; D003922:Diabetes Mellitus, Type 1 / Q000276:immunology; D048049:Extracellular Signal-Regulated MAP Kinases / Q000276:immunology / Q000378:metabolism; D008213:Lymphocyte Activation; D051379:Mice; D008822:Mice, Transgenic; D055650:NK Cell Lectin-Like Receptor Subfamily A / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051058:Oncogene Protein v-akt / Q000276:immunology / Q000378:metabolism; D010766:Phosphorylation / Q000502:physiology; D016755:Proto-Oncogene Proteins c-jun / Q000276:immunology / Q000378:metabolism; D011948:Receptors, Antigen, T-Cell / Q000276:immunology / Q000378:metabolism*; D015398:Signal Transduction / Q000502:physiology; D051746:ZAP-70 Protein-Tyrosine Kinase / Q000276:immunology / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000276:immunology / Q000378:metabolism
D018106:CD28 Antigens; C527088:Klra1 protein, mouse; D055650:NK Cell Lectin-Like Receptor Subfamily A; D016755:Proto-Oncogene Proteins c-jun; D011948:Receptors, Antigen, T-Cell; D051746:ZAP-70 Protein-Tyrosine Kinase; C497262:Zap70 protein, mouse; D051058:Oncogene Protein v-akt; D048049:Extracellular Signal-Regulated MAP Kinases; D048051:p38 Mitogen-Activated Protein Kinases