“Biological activity of UDP-Glc-glucosil transferase (GT) in human circulating B lymphocytes and term placenta”

PRADOS MB, LITWIN S, BARRIENTOS G, GENTILE T AND MIRANDA S.

Graz, Austria

Congreso; 4th European Congress of Reproductive Immunology; 2006

European Society for Reproductive and Developmental Immunology (ESRADI)

BIOLOGICAL ACTIVITY OF UDP-glucose-glucosil transferase (GT) IN HUMAN CIRCULATING B LYMPHOCYTES AND TERM PLACENTA. VARIATIONS WITH PROGESTERONE LEVELS. Prados MB, Litwin S, Barrientos G, Gentile T, Miranda S. IDEHU(CONICET-UBA). Junín 956-4Piso. Buenos Aires-ARGENTINA. 4th European Congress of Reproductive Immunology, Graz, Austria (julio 2006) The role of GT in the quality control of secretor proteins has been ascertained. However, its physiological role remains unknown. We have previously reported that IL-6 levels can modulate its activity in vitro. Here we analyze the enzymatic activity in placenta and circulating B cells and its variations with progesterone (P4) levels. GT activity was determined in murine hybridoma cells cultures in the absence or presence of P4 (10-5;10-6;10-9;10-10M) with or without antiIL-6, in B lymphocytes obtained from woman donors blood and in placental cell suspensions obtained from human term placenta. GT activity was assessed as the incorporation of 14C-Glc to denatured thyroglobulin. The concentration of plasma P4 and of IL-6 in culture supernatants were determined by specific capture immunoassays. In vitro assays showed that GT activity and IL-6 level varied depending on the dose of the added P4. However, after neutralizing IL-6, control cultures and those with P4 10-5M and 10-6M showed similar GT activity. Circulating LB cells showed a wide range of GT activity, which appeared to be related with the plasma P4 levels. Intermediate GT values were detected in placental homogenates. Our results indicate that GT activity can be detected in human term placenta and circulating B cells. In vitro assays showed that the effect of P4 on GT would be mediated by IL-6.