“Participation of UDP-glucosa glucosiltransferase in asymmetric antibody synthesis”

M. B. PRADOS, T. GENTILE AND S. MIRANDA.

Córdoba, Argentina

Congreso; VII Congreso Latinoamericano de Inmunología.; 2005

Asociación Latinoamericana de Inmunología (ALAI) en conjunto con la Sociedad Argentina de Inmunología (SAI), la Sociedad Chilena de Inmunología (SOCHIN), la Sociedad Latinoamericana de Histocompatibilidad (SLAH) y el Grupo de Trabajo de Inmunología Pediát

PARTICIPATION OF UDP-GLC-GLUCOSILTRANSFERASE IN ASYMMETRIC ANTIBODIES SYNTHESIS Prados MB, Gentile T, Miranda S IDEHU(CONICET-UBA) VII Congreso Latinoamericano de Inmunología. Córdoba, Argentina. 2005 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-glucosil transferase (GT). The aim of this work was to study GT activity and AAb production 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. Moreover, GT activity was analized in peripheral blood B cells. B cells were obtained employing CD19 microbeads. Cell viability and purity were >90% as determined by FACS (cells analized: CD3+/CD14+/CD19+). GT activity was determined as the incorporation of 14C-Glc to denatured thyroglobulin. AAb proportion was calculated by ELISA. Results show that Pg 10-6, 10-9 y 10-10 M diminished GT activity (-26±5%, -21±3% y -28±4%) and varied AAb proportion (-50±4%, 0±3% y +39±2%). The adition of anti/IL-6 inhibited the effects produced by Pg on GT activity and AAb production only when Pg concentration was 10-6M. Pg 10-5M increased GT activity (18±4%). E2 10-7M increased GT activity in a 22±5% not modifying AAb (0±5%), whereas E2 10-8M diminished GT activity (-28±3%) and AAb (-62±3%), a value that was not modified by the adition of anti/IL-6. B cells showed a GT activity between 0.92-1,5cpm/ug. This work shows that there is a dose dependent regulation of GT activity by E2 and Pg in vitro. Pg might modulate AAb production by two intracellular mechanisms: Pg 10-10 M has an estimulatory effect wich does not depends on IL-6 and GT, whereas Pg 10-6 M has an inhibitory effect regulated by IL-6 and GT. The inhibitory effect produced by E2 (10-8 M) might not depend on IL-6 and GT. Considering that there is a high GT expression in placenta and that Pg levels are around 10-5M at maternofetal interfase, these results suggest that GT might have a role in maternofetal tolerance.