Development and characterisation of an ultrasensitive monoclonal antibody for chloramphenicol

In this study, a highly sensitive monoclonal antibody (McAb) against chloramphenicol (CAP) was successfully raised and characterised by indirect competitive enzyme-linked immunosorbent assay (ic-ELISA). Three antigens coupled with different proteins were synthesised and determined by the UV-vis method. After five rounds of immunisation, antisera were collected from six Balb/C mice and screened by ic-ELISA. The standard inhibition curve of one CAP McAb (labelled 6F11) showed the best sensitivity to CAP after optimisation of the principal working conditions. The half-maximal inhibition concentration (IC₅₀) was calculated to be 0.01 ng/mL and the linear working range was from 0.0028 ng/mL to 0.040 ng/mL with a correlation coefficient of 0.996. This McAb showed high specificity, with negligible cross-reactivities detected towards CAP analogues (florfinicol, florfinicol amine, thiamphenicol). The recovery rate was 98.9–106.8% while the coefficient of variation was 4.45–6.05%. The IC₅₀ value and other parameters obtained for this CAP McAb suggest that it is likely to have a promising future in further applications in combination with different analytical techniques.