A general strategy to control antibody specificity against targets showing molecular and biological similarity: Salmonella case study.

The control of antibody specificity plays pivotal roles in key technological fields such as diagnostics and therapeutics. During the development of immunoassays (IAs) for the biosensing of pathogens in food matrices, we have found a way to rationalize and control the specificity of polyclonal antibodies (sera) for a complex analytical target (the Salmonella genus), in terms of number of analytes (Salmonella species) and potential cross-reactivity with similar analytes (other bacteria strains). Indeed, the biosensing of Salmonella required the development of sera and serum mixtures displaying homogeneous specificity for a large set of strains showing broad biochemical variety (54 Salmonella serovars tested in this study), which partially overlaps with the molecular features of other class of bacteria (like specific serogroups of E. coli). To achieve a trade-off between specificity harmonisation and maximization, we have developed a strategy based on the conversion of the specificity profiles of individual sera in to numerical descriptors, which allow predicting the capacity of serum mixtures to detect multiple bacteria strains. This approach does not imply laborious purification steps and results advantageous for process scaling-up, and may help in the customization of the specificity profiles of antibodies needed for diagnostic and therapeutic applications such as multi-analyte detection and recombinant antibody engineering, respectively.

Production of polyclonal antibodies directed to recombinant methionyl bovine somatotropin.

The administration of recombinant methionyl bovine somatotropin (rMbST) to dairy cows to increase milk yield remains a common practice in many countries including the USA, Brazil, Mexico, South Africa and Korea, whereas it has been forbidden within the European Union (EU) since 1999. A rapid screening immunoanalytical method capable of the unequivocal determination of rMbST in milk would be highly desirable in order to effectively monitor compliance with the EU-wide ban for home-made or imported dairy products. For decades, the production of specific antibodies for this recombinant isoform of bovine somatotropin (bST) has remained elusive, due to the high degree of sequence homology between both counterparts (e.g. methionine for rMbST in substitution of alanine in bST at the N-terminus). In this study, we compared several immunizing strategies for the production of specific polyclonal antibodies (pAbs), based on the use of the full-length recombinant protein, an rMbST N-terminus peptide fragment and a multiple antigen peptide (MAP) which consists of an oligomeric branching lysine core attached to the first two N-terminus amino acids of rMbST, methionine and phenylalanine (MF-MAP). The immunization with KLH-conjugated MF-MAP led to the production of the pAb with the highest rMbST/bST recognition ratio amongst the generated battery of antibodies. The pAb exhibited a specific binding ability to rMbST in a competitive antigen-coated ELISA format, which avidity was further improved after purification by rMbST N-terminus peptide-based affinity chromatography. These results suggest that immunodiscrimination between structurally related proteins can be achieved using immuno-enhanced immunogens such as MAPs.

Study of the pharmacokinetic interaction between simvastatin and prescription omega-3-acid ethyl esters.

The coadministration of prescription omega-3-acid ethyl esters (P-OM3) with a statin may present a treatment option for patients with mixed hyperlipidemia. This open-label, randomized, 2-way crossover, drug-drug interaction study evaluated the impact of P-OM3 capsules on plasma simvastatin pharmacokinetics in 24 healthy volunteers. Under fasted conditions, 80 mg simvastatin was administered with or without 4 g P-OM3 for two 14-day periods. After 14 days of dosing to achieve steady state, no significant differences were found in either the extent (AUC(tau)) or rate (Cmax) of exposure to simvastatin or its major beta-hydroxy metabolite after coadministration of P-OM3 with simvastatin compared with administration of simvastatin alone. At steady state, the coadministration of P-OM3 capsules did not appear to affect the pharmacokinetics of simvastatin tablets. The combination of P-OM3 capsules and simvastatin appeared to be well tolerated.