Age-associated changes in CD90 expression on thymocytes and in TCR-dependent stages of thymocyte maturation in male rats.
To elucidate the effects of ageing on T-cell-maturation, in 3- and 18-month-old rats, we analysed the expression of: (i) CD4/CD8/TCRalphabeta and (ii) Thy-1, which is supposed to be a regulator of TCRalphabeta signalling, and thereby the thymocyte selection thresholds. Since an essential role for TCRalphabeta signalling in the development of CD4+25+T(reg)-cells was suggested, the frequency of these cells was also quantified. We demonstrated that, as for mice, early thymocyte differentiational steps within the CD4-8- double negative (DN) developmental stage are age-sensitive. Furthermore, we revealed that TCRalphabeta-dependent stages of T-cell development are affected by ageing, most likely due to an impaired expression of Thy-1 on TCRalphabeta(low) thymocytes entering selection processes. The diminished frequency of the post-selection CD4+8+ double positive (DP) cells in aged rats, together with an overrepresentation of mature single positive (SP) cells, most probably suggests more efficient differentiational transition from the DP TCRalphabeta(high) to the SP TCRalphabeta(high) developmental stage, which is followed by an increase in pre-migration proliferation of the mature SP cells. Moreover, the study indicated impaired intrathymic generation of CD4+25+T(reg)-cells in aged rats, thus providing a possible explanation for the increased frequency of autoimmune diseases in ageing.
Leposavić
Gordana
G
Institute of Immunology and Virology Torlak, Immunology Research Center Branislav Janković, Belgrade, Serbia and Montenegro. gordana.leposavic@pharmacy.bg.ac.yu
Pesić
Vesna
V
Kosec
Dusko
D
Radojević
Katarina
K
Arsenović-Ranin
Nevena
N
Pilipović
Ivan
I
Perisić
Milica
M
Plećas-Solarović
Bosiljka
B
D000375:Aging / Q000276:immunology*; D000818:Animals; D000954:Antigens, Surface / Q000235:genetics / Q000502:physiology; D017209:Apoptosis / Q000502:physiology; D001327:Autoimmune Diseases / Q000276:immunology; D015704:CD4 Antigens / Q000235:genetics / Q000502:physiology; D016827:CD8 Antigens / Q000235:genetics / Q000502:physiology; D002465:Cell Movement; D049109:Cell Proliferation; D005786:Gene Expression Regulation; D053645:Interleukin-2 Receptor alpha Subunit / Q000235:genetics / Q000502:physiology; D037181:Lectins, C-Type / Q000235:genetics / Q000502:physiology; D008297:Male; D055651:NK Cell Lectin-Like Receptor Subfamily B; D051381:Rats; D017208:Rats, Wistar; D016693:Receptors, Antigen, T-Cell, alpha-beta / Q000235:genetics / Q000502:physiology*; D018800:Thy-1 Antigens / Q000235:genetics / Q000378:metabolism*; D013950:Thymus Gland / Q000166:cytology* / Q000276:immunology
D000954:Antigens, Surface; D015704:CD4 Antigens; D016827:CD8 Antigens; D053645:Interleukin-2 Receptor alpha Subunit; D037181:Lectins, C-Type; D055651:NK Cell Lectin-Like Receptor Subfamily B; D016693:Receptors, Antigen, T-Cell, alpha-beta; D018800:Thy-1 Antigens