Estradiol-dependent perforin expression by human regulatory T-cells.
BACKGROUND
CD4+CD25+FoxP3+ regulatory T-cells (nT(Reg)) have been shown to suppress immune responses to autoantigens and to other diverse antigens, this suppression is mainly mediated by a cell contact-dependent mechanism not yet fully defined. It has been reported that both human natural and induced T(Reg) exert cytotoxic activity against autologous target cells, which suggests that the perforin/granzyme pathway may be a relevant candidate mechanism for the suppressive function of T(Reg). Previous reports have shown that oestradiol (E2) modulates T(Reg) percentages and function.


METHODS
We have evaluated in pregnant and non-pregnant subjects perforin intracellular expression in CD4+CD25+FoxP3+ regulatory T-cells by flow cytometry in whole blood, ex-vivo purified nT(Reg) and ex-vivo purified nT(Reg) after TCR and E2 stimulation. The expression of cellular degranulation markers was also phenotypically determined.


RESULTS
We show that E2 expands T(Reg), enhances in vitro T(Reg) function and induces a T(Reg) phenotype in activated responder (CD4+CD25) T-cells, further increasing the expression of perforin on T(Reg) than in vitro T-cell receptor activation alone. We found surface lysosomal-associated membrane glycoproteins (LAMP)-1 and LAMP-2 expression by T(Reg), which is a sign of cell degranulation and therefore of cytotoxicity exerted by these cells.


CONCLUSIONS
Our data demonstrates the presence of functional T(Reg) cytotoxic properties in biological systems and support the concept that E2 enhances the number and function of T(Reg) suggesting the potential interaction between E2 and immunoregulatory mechanisms.
Department of Immunology, Hospital General Universitario Gregorio Marañón, Madrid, Spain.
Larissa
L
Valor
Roseta
R
Teijeiro
Carol
C
Aristimuño
Florence
F
Faure
Bárbara
B
Alonso
Clara
C
de Andrés
Marta
M
Tejera
Nieves
N
López-Lazareno
Eduardo
E
Fernández-Cruz
Silvia
S
Sánchez-Ramón
D000328:Adult; D000818:Animals; D004958:Estradiol / Q000276:immunology / Q000378:metabolism / Q000494:pharmacology*; D005260:Female; D005434:Flow Cytometry; D051858:Forkhead Transcription Factors / Q000276:immunology / Q000378:metabolism; D053804:Granzymes / Q000276:immunology / Q000378:metabolism; D006801:Humans; D007108:Immune Tolerance; D008213:Lymphocyte Activation / Q000276:immunology*; D051379:Mice; D008810:Mice, Inbred C57BL; D054353:Perforin / Q000276:immunology / Q000378:metabolism*; D011247:Pregnancy; D011948:Receptors, Antigen, T-Cell / Q000378:metabolism; D013223:Statistics as Topic; D050378:T-Lymphocytes, Regulatory / Q000276:immunology* / Q000378:metabolism*
D051858:Forkhead Transcription Factors; D011948:Receptors, Antigen, T-Cell; D054353:Perforin; D004958:Estradiol; D053804:Granzymes