Abstract
This work comprises studies into the application of the enzyme-linked immunosorbent assay for ABH grouping as it applies to forensic serology. The detection of groups A, B and H substance in liquid saliva and bloodstains on cotton cloth were studied by ELISA. Assays were developed to group A and B substance in 0.40 $________mu$l of liquid saliva using commercial polyclonal antisera in a two-stage indirect ELISA. The use of human immune sera to group ABH substance in extracts of bloodstains was confounded by reaction of anti-human Ig conjugates with immunoglobulin from the stain extract co-immobilizing with extracted blood group substance. Several anti-ABH monoclonal antibodies were used to successfully type groups A, B and O secretor saliva and groups A$________sb1$, B and A$________sb1$B bloodstains extracted with a combination of detergents and ammonia. Group O stains were not detectable because the anti-H reagent was of insufficient titre. The MAb were purified on immunoadsorbents and by size exclusion chromatography and partially characterised. Attempts were made to conjugate purified MAb to alkaline phosphatase by the glutaraldehyde, the SPDP method (3-(2-pyridyldithio) propionic acid N-hydroxy succinimide ester) and using the avidin-biotin system. The latter was most successful although problems were encountered with endogenous biotin. The implications of these findings and suggestions for further study are discussed.