Effect of aging on T lymphocyte activation

Studies of the early stages of T-cell activation reveal that T cells from a ged mice show multiple abnormalities within the first few minutes after sti mulation, including decline in the activation of the Raf-1/MEK/ERK kinases and in JNK protein kinase. Zap-70 kinase associated with the CD3 zeta chain shows a 2-fold increase with age in resting CD4 T cells, despite a three-f old decline with age in the levels of tyrosine phosphorylation of CD3 zeta; nonetheless, there is no effect of aging on Zap-70 kinase function in acti vated T cells as measured by in vitro kinase methods. Age-related impairmen t of the translocation of PKC theta from cytoplasm to the site of T-cell in teraction with antigen-presenting cells may underlie downstream defects in the activation cascade. (C) 2000 Elsevier Science Ltd. All rights reserved.