N-acetylcysteine added to saliva does not affect IgA concentration or the agglutination of Streptococcus mutans in vitro.

N-acetylcysteine (NAC) or placebo were mixed with parotid or whole saliva to a final concentration of 0.004-10 mg/ml saliva. Placebo and NAC-containing parotid saliva had the same bacterial agglutinating capacity for 4 strains of Streptococcus mutans. Immunoglobulin A (IgA) concentration in whole saliva, using ELISA and single radial immunodiffusion assays, did not reveal any differences between NAC and placebo-treated samples. NAC did not affect the immunoelectrophoretic pattern of IgA.