Detection of Neisseria meningitidis group A, Haemophilus influenzae type b, and Streptococcus pneumoniae antigens in cerebrospinal fluid specimens by antigen capture enzyme-linked immunosorbent assays.

Antigen capture enzyme-linked immunosorbent assay was compared to coagglutination and counterimmunoelectrophoresis for the detection of meningococcal, Haemophilus, and pneumococcal antigens. Enzyme-linked immunosorbent assay detected 1 ng of purified meningococcal and Haemophilus polysaccharides per ml and 5 ng of pneumococcal polysaccharide per ml; coagglutination detected 20, 25, and 30 ng/ml, respectively, of these polysaccharides; and counterimmunoelectrophoresis detected 10, 50, and 60 ng/ml. Double-antibody sandwich-antiglobulin enzyme-linked immunosorbent assays, which employed antibodies produced in two animal species, differentiated 100% of the cerebrospinal fluid (CSF) specimens from meningococcal meningitis patients and 95% of the CSFs from Haemophilus patients from heterologous control CSFs. Double-antibody sandwich procedures, which use the same antiserum preparation for coating the wells of microtiter plates and for alkaline phosphatase-conjugated immunoglobulin, differentiated meningococcal CSFs from control specimens but were unable to effectively differentiate the Haemophilus or pneumococcal specimens from control CSFs. Coagglutination detected specific antigen in 92% of the meningococcal CSFs, 80% of the Haemophilus CSFs, and 92% of the pneumococcal specimens. The comparable percentages for counterimmunoelectrophoresis were 76, 95, and 71%.