Drugs affecting the release of rheumatoid factor in a plaque-forming cell assay.

Addition of propranolol to the agarose phase of a plaque-forming cell (PFC) assay for rheumatoid factor (RF) caused reduction in the number of plaques seen. This reduction in rheumatoid factor plaque-forming cell (RF PFC) did not depend upon an effect at the beta-adrenergic receptor, since d- and 1-propranolol reduced equally well. Furthermore, in a series of polycyclic compounds with varying beta-receptor blocking capabilities there was no agreement between plaque reduction and blocking. When propranolol was tested in the agarose in an anti-sheep erythrocyte (SRC) plaque assay (anti-SRC PFC), it had no inhibitory effect, but it was capable of inhibiting the generation of new anti-SRC PFC in an in vitro culture. Propranolol is thought to exert these effects through its membrane stabilizing (anesthetic) properties.