• B-lymphocytes;
  • blocking antibodies;
  • cytokines;
  • placenta

Canellada A, Färber A, Zenclussen AC, Gentile T, Dokmetjian J, Keil A, Blois S, Miranda S, Berod L, Gutiérrez G, Markert UR, Margni RA. Interleukin regulation of asymmetric antibody synthesized by isolated placental B cells. AJRI 2002; 48: 275–282 © Blackwell Munksgaard, 2002

PROBLEM: Protecting antibodies against trophoblast surface molecules were previously described. Here we analysed the synthesis of asymmetric IgG by placental B-lymphocytes.

METHOD OF STUDY: B cells were isolated from human term placenta and cord blood, stimulated with anti-CD40 IgG and cocultured with transfected Fcγ R-expressing mice Ltk-fibroblast. Interleukin-4, IL-6, IL-10, IL-11 and IL-13 were added to cultures for 14 days. Asymmetric IgG were assessed in culture supernatants by concanavalin A (Con A) fixation and enzyme-linked immunosorbent assay.

RESULTS: When IL-6 was added to the cultures, the percentages of asymmetric IgG synthesized by placental B cells were: IL-6: 29 ± 10; IL-6 + IL-10: 24 ± 7; IL-4 + IL-10 + IL-6: 38 ± 9. The last combination induced the highest increase in the asymmetric IgG synthesis as compared with control (19 ± 10%, P < 0.05). Additionally, placental B cells synthesized more asymmetric IgG than umbilical cord blood B-lymphocytes (P=0.0015).

CONCLUSIONS: Isolated placental B-lymphocytes synthesized asymmetric IgG in response to Th2 interleukins, more notably IL-6 in combination with IL-4 and IL-10. The in vitro increase of protective asymmetric IgG synthesis in response to Th2-cytokines support the hypothesis that a local Th2-switch is beneficial for pregnancy outcome.