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Failure of Rearranged TCR Transgenes to Prevent Age-Associated Thymic Involution

1999; American Association of Immunologists; Volume: 163; Issue: 8 Linguagem: Inglês

10.4049/jimmunol.163.8.4262

1550-6606

H. Daniel Lacorazza, José A. Guevara Patiño, Marc E. Weksler, Dorel L. Radu, Janko Nikolić‐Žugić,

Immune Cell Function and Interaction

After puberty, the thymus undergoes a dramatic loss in volume, in weight and in the number of thymocytes, a phenomenon termed age-associated thymic involution. Recently, it was reported that age-associated thymic involution did not occur in mice expressing a rearranged transgenic (Tg) TCRalphabeta receptor. This finding implied that an age-associated defect in TCR rearrangement was the major, if not the only, cause for thymic involution. Here, we examined thymic involution in three other widely used MHC class I-restricted TCRalphabeta Tg mouse strains and compared it with that in non-Tg mice. In all three TCRalphabeta Tg strains, as in control mice, thymocyte numbers were reduced by approximately 90% between 2 and 24 mo of age. The presence or absence of the selecting MHC molecules did not alter this age-associated cell loss. Our results indicate that the expression of a rearranged TCR alone cannot, by itself, prevent thymic involution. Consequently, other presently unknown factors must also contribute to this phenomenon.