Influence of progesterone and estrogen on UDP-Glc-glucosiltransferase activity and asymmetric antibodies synthesis

PRADOS MB; GENTILE T; MIRANDA S

CABA

Taller; Taller satélite del II Simposio Latinoamericano de Interacción Materno-Fetal y Placenta; 2005

Facultad de Farmacia y Bioquímica (UBA), Facultad de Medicina (UBA) y CEFYBO (CONICET-UBA)

INFLUENCE OF PROGESTERONE AND ESTROGEN ON UDP-GLC-GLUCOSILTRANSFERASE ACTIVITY AND ASYMMETRIC ANTIBODIES SYNTHESIS MB Prados, T.Gentile, S.Miranda IDEHU(CONICET-UBA) Asymmetric antibodies (AAb) constitute an important factor in materno-fetal tolerance. It has been demonstrated that its synthesis is regulated by IL-6 by means of UDP-glucose-glucosiltransferase (GT). We studied GT activity, AAb production and IL-6 synthesis by a murine hibridoma in the absence or presence of estrogen (E2) (10-7 y 10-8M) or progesterone (Pg) (10-5, 10-6, 10-9, 10-10M) with or without anti/IL-6. GT activity was also analized in peripheral blood B cells. B cells were obtained employing CD19 microbeads. Cell purity was determined by FACS. GT activity was determined as the incorporation of 14C-Glc to denatured thyroglobulin. AAb rate and IL-6 concentration were calculated by ELISA. In the presence of Pg 10-6, 10-9 and 10-10M hybridoma cells showed the same GT activity whereas this activity was significantly increased during the treatment with Pg 10-5M. AAb ratio was similar in the cultures treated with Pg 10-5M and Pg 10-6M but it was significantly higher when the concentration was 10-9M and 10-10M. E2 modulated GT activity and AAb ratio in the conditions tested. Pg but not E2 modified IL-6 level in a hybridoma cell culture. The neutralizing anti-IL-6 antibody did not affect the increase in the AAb ratio induced by Pg 10-10M whereas it abolished the decrease in GT activity and AAb ratio in the presence of Pg 10-6M. B cells isolated from peripheral blood showed a viability and purity index superior to 90%. GT activity in these cells was around 0.92-1,5cpm/mg of microsomal fraction protein. Considering that Pg concentration in decidua is around 10-5M, the increase of GT biological activity observed in this work agrees with the high placental GT mRNA expression reported. This activity level, however, was not accompanied with an increased AAb ratio in vitro, an expected result considering the high asymmetric IgG level found in placenta. The IL-6 level induced by Pg might not affect AAb ratio in vitro, though it may play a role in the modulation of GT activity.