[Detection of hybrid cells secreting monoclonal immunoglobulins using Staphylococcus aureus agglutination].

A quantitative assay for mouse monoclonal immunoglobulins (Ig) was made possible by a very simple and sensitive co-agglutination test. Staphylococci which were rich in protein A were used in the presence of sheep anti-mouse IgG (H + L) antibodies. The assay was conducted in a single step using micro-haemagglutination plates. Plates were scored after over-night incubation. This method could detect as little as 0.006 microgram of IgG/ml. One set of hybrids was screened both by this method and by an immunoenzymatic assay (ELISA): with one exception, all clones which were found to produce Ig by ELISA were also positive by co-agglutination. Moreover, the co-agglutination method detected 7 additional Ig-secreting cultures. The level of secretion of each positive hybridoma ranged from 0.2 to 2 micrograms/ml. Thus, when compared to ELISA, the co-agglutination test was not only just as sensitive, but was also much simpler and faster.