Monoclonal blood group antibodies.

The large volume requirements for high quality AB0 and RhD typing reagents can now be supplied by selected monoclonal antibodies. Superior anti-A and anti-B monoclonal reagents are each prepared from blends of two antibodies to optimise the intensity of agglutination for slide tests and the potency for detection of the weaker sub-groups, including Ax and Bw by tube techniques. Excellent anti-A,B reagents must also be made by blends of at least two antibodies to optimise both A and B reactions, but the need for their continued use is now debatable. The development of high titre IgM monoclonal anti-D reagents offers simple rapid saline RhD typing of both patients and donors, but they cannot reliably detect weak D (Du) and some D variants (Cat. VI). However, this can be achieved by blending IgG (polyclonal) anti-D with the IgM anti-D which can detect these types (in donor bloods) after conversion of negative saline tests to an antiglobulin phase. Selected monoclonal anti-complement blended with conventional anti-IgG can provide excellent polyspecific anti-human globulin reagents free of 'false positives' in routine tests. Monoclonal anti-M and -N require careful pH adjustment for optimum reactions. All anti-N reagents must be carefully diluted for reliable detection of heterozyotes, but with freedom of cross reaction with S + MM cells that have the most 'N' that is not a product of the N gene. Specific anti-M monoclonal antibodies can occur and an example is described that does not agglutinate NN cells even as a neat supernatant.