Abstract: Streptococcus mutans in saliva or dental plaque collected from the oral cavity can be measured by the method of the present invention conveniently with high sensitivity without the performance of any complex procedure, such as culturing. The reactivity of the antibody of the present invention against Streptococcus mutans is 1000-fold or more greater than its reactivity against each of Streptococcus gordonii, Streptococcus salivarius, Streptococcus oralis, Streptococcus mitis, and Streptococcus sanguis.

Abstract: The present invention provides an immunological method for the assay of Streptococcus sobrinus participating in dental caries, an antibody for use in the method, and a diagnostic kit. As the antibody, there is used an antibody whose binding ability for Streptococcus sobrinus is not less than 100 times that for Streptococcus mutans.

Abstract: There are provided: an immunological reagent for diagnosis of or the evaluation of the effect of a medicine for dialysis-related amyloidosis, which includes an antibody which reacts specifically with a carboxymethylated .alpha.-amino acid, a carboxymethylated protein, or a carboxymethylated peptide; or, an immunological reagent for diagnosis of or the evaluation of the effect of a medicine for diabetes mellitus and diabetes mellitus complications, which includes an antibody which reacts specifically with an N.sup..alpha. -carboxymethylated .alpha.-amino acid, an N.sup..alpha. -carboxymethylated protein, or an N.sup..alpha. -carboxymethylated peptide. Methods using the immunological reagents are provided: for determination of carboxymethylated hemoglobin as a marker for dialysis-related amyloidosis; or, for determination of N.sup..alpha. -carboxymethylated hemoglobin as a marker for diabetes mellitus or diabetes mellitus complications.