The Inhibitory Effects of Progesterone on Human T Cell Proliferative Signals

• Main Authors: Wen-Feng Lee, 李文峰
• Other Authors: Eileen Jea Chien, Ph.D.
• Format: Others
• Language: zh-TW
• Published: 2002
• Online Access: http://ndltd.ncl.edu.tw/handle/965kar

碩士 === 國立陽明大學 === 生理學研究所 === 90 === Fetal alloantigens encoded by genes inherited from the father should provoke responses by maternal T cells leading to fetal loss. However, progesterone may be an immunomodulator is important for the survival of the implanting embryo and maintenance of early pregnancy. Our previous studies demonstrate that both Ca2+ influx and alkalinization are early proliferative signals in T cells activated by a mitogen, phytohemagglutinin (PHA). Progesterone, at concentrations found in placenta, inhibits the proliferation of lymphocytes by mitogens. The aim of this study was to investigate whether progesterone affected T cell activation signals on intracellular calcium ([Ca2+]I), pH (pHi) as to influence PHA-induced IL-2, IL-4 secretion, CD25, CD28, CD152 expression and proliferation. T cells were isolated from human peripheral blood. The [Ca2+]i and the pHi were measured using the fluorescent dyes, Fura-2 and BCECF, respectively. PHA was used as a control. The expressions of NFkB and IL-2Ra mRNA were analyzed by RT-PCR (reverse transcriptase-polymerase chain reaction). The expressions of T cell surface antigens, CD25, CD28, and CD152 (CTLA-4), were detected by the flow cytometry. The IL-2, IL-4 secretion were measured by ELISA (enzyme-linked immunosorbent assay). The proliferation was determined by [3H]-thymidine incorporation into T cells. The results indicated that 1) progesterone (100 mM) resulted in an elevation of [Ca2+]i in T cells within 15 min, from a resting level of 95.2±10.42 nM to 141.9±12.8 nM (n=10，p<0.001), and a decrease of pHi (acidification) within 30 min, from 7.312±0.077 to 6.952±0.079 (n=10，p<0.001). 2) The responses on acidification and the [Ca2+]i increase by progesterone were suppressed by progesterone antagonist, RU486. The [Ca2+]i increased by progesterone was dependent on Ca2+ influx, whereas, acidification was PKC、Ca2+、Na+-dependent. PHA did not affect progesterone-induced acidification, but progesterone could suppress PMA or PHA-induced alkalinization. 3) The peak expressions of NFkB and IL-2Ra mRNA were at 0.5 hr and 2 hr after progesterone administration. 4) PHA stimulated the expressions of CD25, CD28, CD152 and secretions in IL-2, IL-4, but progesterone could significantly suppress PHA-induced CD25, CD28 expression and IL-2, IL-4 secretion in T cells. 5) Progesterone alone did not influence [3H]-thymidine incorporation into T cells. However, progesterone could suppress PHA-induced [3H]-thymidine uptake. In conclusion, progesterone stimulates intracellular calcium elevation, acidification and NFkB mRNA expression but Inhibits PHA-induced alkalinization, IL-2, IL-4 secretion, CD25, CD28 expression and proliferation in T cells. These results implied that acidification by progesterone might be an essential mechanism to suppress PHA-induced T cell activation.