All ABI antibodies work in ELISA; however, it is critical to use an antigen preparation that has enough of the target protein at a sufficient purity to allow the antibody to "find" it. One of the major reasons for an antibody "not working" in ELISA is that quite often the antigen being used has so much non-relevant protein as compared to the target protein that the non-relevant protein occupies most of the available binding sites during coating. The target protein is not able to bind to the microplate plastic in sufficient quantity to allow detection by the antibody, and the results seem to indicate that the antibody did not work. Try a partial purification of the protein or, if the protein is structural (ie., part of the virion), try purified virus rather than an infected cell extract.