Effect of serum–antigen incubation times on the expression of non-specific inhibitors of rubella hemagglutination

Abstract

Under certain conditions, serum very low-density lipoproteins (VLDL) and high-density lipoproteins (HDL) can inhibit rubella hemagglutination. The level of this non-specific hemagglutination-inhibition (HI) activity increases as the incubation period between serum and antigen is increased. Treatment of serum with heparin–MnCl2 does not precipitate HDL, and may not effect complete removal of all VLDL. This treatment method, therefore, should be considered a source of false-positive reactions, especially when extended serum–antigen incubation periods are used to enhance HI activity and to detect low levels of IgM.