Steroid sensitivity of thymocyte subpopulations during intrathymic differentiation. Effects of 17 beta-estradiol and dexamethasone on subsets expressing T cell antigen receptor or IL-2 receptor.
We have studied the effects of the steroid hormones, 17 beta-estradiol and dexamethasone, on the relative proportion of thymocyte expression of CD4 (L3T4), CD8 (Ly-2), TCR and IL-2R, used to identify different stages of thymocyte differentiation. After short-term in vivo steroid treatment, a significant decrease in the number and proportion of the CD4+/CD8+, double positive subpopulation was observed in parallel with a proportional increase in the percentage of the CD4+/CD8- single positive, of the CD4-/CD8-, double negative and, to a lesser extent, of the CD8+/CD4- subsets. Either steroid treatment increased the proportion of cells expressing either the epsilon-chain of the CD3 complex and/or the beta-chain of the TCR (beta-TCR) (TCR+/CD3+) and the 55 kDa protein of the IL-2R (IL-2R+), related to the increase of CD4+ SP thymocytes and of DN cells, respectively. Furthermore, the increased proportion of CD3+ cells could also be partially related to the increase of both the CD4+ and DN subsets. A decrease of the effect on either DN/IL-2R+ cells or CD4+ SP cells was selectively observed after long-term treatments with 17 beta-estradiol or DEX, respectively. It is concluded that after short-term administration, different steroid hormones mediate a similar selective depletion of DP, TCR-/CD3-, IL2R- cells presumably in an intermediate stage of differentiation. However, either steroid effects evolve differently in long-term treatment schedules, resulting in different effects on early (DN/IL2R+) and late (SP/IL2R-) steps of thymocyte differentiation.
Screpanti
I
I
Department of Experimental Medicine, University La Sapienza, Rome, Italy.
Morrone
S
S
Meco
D
D
Santoni
A
A
Gulino
A
A
Paolini
R
R
Crisanti
A
A
Mathieson
B J
BJ
Frati
L
L
D000818:Animals; D000945:Antigens, Differentiation, T-Lymphocyte; D002454:Cell Differentiation / Q000187:drug effects; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D007958:Leukocyte Count / Q000187:drug effects; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008970:Molecular Weight; D010641:Phenotype; D011948:Receptors, Antigen, T-Cell / Q000032:analysis* / Q000187:drug effects; D015375:Receptors, Interleukin-2 / Q000032:analysis* / Q000187:drug effects; D013601:T-Lymphocytes / Q000145:classification* / Q000378:metabolism / Q000502:physiology; D013950:Thymus Gland / Q000187:drug effects / Q000378:metabolism / Q000502:physiology*; D013997:Time Factors
D000945:Antigens, Differentiation, T-Lymphocyte; D011948:Receptors, Antigen, T-Cell; D015375:Receptors, Interleukin-2; D004958:Estradiol; D003907:Dexamethasone