PROBLEM: The in vivo effect of soluble factors present in placental culture supernatants (PCSs) on the synthesis of rat immunoglobulin E (IgE) and IgG2a isotypes was investigated.
METHOD OF STUDY: Batches of Wistar SPF rats immunized with a 10-μg dose of ovalbumin and Al(OH)3 were used: group I, consisted of virgin rats; group II, virgin females injected simultaneously with PCSs; and group III, pregnant females. As controls, nonimmunized batches were included. Serum samples were collected at days 0 (basal) and 10 after antigen challenge, determining levels of total and specific antiovalbumin of both IgE and IgG2a by enzyme-linked immunoadsorbent assay (ELISA).
RESULTS: In vivo and at least at the doses administered, PCSs exert an inhibitory effect on the synthesis of specific and total anti-ovalbumin IgE during the course of immune response to such challenge. However, PCSs did not modify serum values of total and specific IgG2a.
CONCLUSIONS: These results suggest that PCSs exert selective influence on the synthesis of diverse immunoglobulin isotypes during immune response, through the balance of cytokines synthesized by placental cells.