Determining lactococcal agglutination by ELISA

An enzyme-linked immunosorbent assay (ELISA) was developed to determine the susceptibility of Lactococcus cultures to bind bovine milk IgM, IgG and IgA. Agglutination susceptible (agg(+)) cultures bound high (P<0.05) concentrations of IgM, IgG and IgA, whereas agglutination resistant (agg(-)) strains bound less. The agglutination variable (agg(+)) cultures differed from the agglutination resistant (agg(-)) cultures only in their ability to bind IgG. The ELISA was a reliable indicator of agglutination susceptibility for mixed as well as single strain cultures. Laser Scanning Microscopy (LSM) was used to verify results of ELISA. The IgG ELISA described here may provide a rapid, sensitive and a reliable method for identification and selection of agg(-) cultures.