Improvement in sensitivity of enzyme-linked immunosorbent assay for tumour necrosis factor

Various protocols were used in the development of enzyme-linked immunosorbent assays (ELISA) to improve the sensitivity and range of detection of human tumour necrosis factor-alpha (TNF-alpha). ELISA can provide a specific, sensitive and rapid method for detection of TNF-alpha in patient's sera, and it is important that the assay used should be sufficiently sensitive to detect low levels of TNF-alpha. The double sandwich ELISA proved to be the most sensitive, detecting less than 0.080 ng/mL TNF. Of eight different protocols, one assay using a purified monoclonal antibody to human TNF-alpha and rabbit polyclonal anti-TNF-alpha antibody had the greatest sensitivity and range of detection. The study illustrates methods for the development of sensitive immunoassays which may have applications in many assay systems.