Antibodies against the antibiotics: an overview

Antibiotics are small molecules used in the treatment of diseases due to pathogenic microorganisms such as bacteria, viruses, fungi. They have different mechanisms of actions and by exploiting their selective toxicity on the infecting microorganism they do not necessarily damage the host cell. Assay for antibiotic concentrations in blood, urine and other body fluids is motivated primarily in conjunction with antibiotic pharmacology and pharmacokinetics to: a) establish the therapeutic levels of the drug; b) monitor antibiotics with narrow toxic/therapeutic ratios; c) detect accumulation of the antibiotic metabolites. The assay used to measure a wide variety of antibiotics is based on the intrinsic capability of these molecules to inhibit the growth of a suitable microorganism. In the last few years other types of tests, e.g., enzyme immunoassays, have been developed based on polyclonal and monoclonal antibodies. Antibodies against non antigenic molecules like antibiotics can be raised by using as antigen the antibiotic (hapten), conjugated with a carrier protein. Polyclonal antibodies containing mixed populations of antibodies (against different antigenic sites of the hapten, the carrier and the site of conjunction between the hapten and the carrier) are largely used to set up enzyme immunoassays for antibiotics. Monoclonal antibodies by recognizing one antigenic site of the hapten have a better specificity but sometimes less affinity than polyclonals. In the case of antibiotics, to raise monoclonal antibodies with good affinity it is important to use targeted immunization and screening strategies that utilize the antibiotic conjugated in different ways to different carriers.(ABSTRACT TRUNCATED AT 250 WORDS)