Production and characterization of polyclonal and monoclonal antibodies against Aflatoxin B1 oxime-BSA in an enzyme-linked immunosorbent assay

Aspergillus-specific antibodies - Targets and applications

Aspergillus is a fungal genus comprising several hundred species, many of which can damage the health of plants, animals and humans by direct infection and/or due to the production of toxic secondary metabolites known as mycotoxins. Aspergillus-specific antibodies have been generated against polypeptides, polysaccharides and secondary metabolites found in the cell wall or secretions, and these can be used to detect and monitor infections or to quantify mycotoxin contamination in food and feed. However, most Aspergillus-specific antibodies are generated against heterogeneous antigen preparations and the specific target remains unknown. Target identification is important because this can help to characterize fungal morphology, confirm host penetration by opportunistic pathogens, detect specific disease-related biomarkers, identify new candidate targets for antifungal drug design, and qualify antibodies for diagnostic and therapeutic applications. In this review, we discuss how antibodies are raised against heterogeneous Aspergillus antigen preparations and how they can be characterized, focusing on strategies to identify their specific antigens and epitopes. We also discuss the therapeutic, diagnostic and biotechnological applications of Aspergillus-specific antibodies.

Aflatoxins B1 in different grades of chillies (Capsicum annum L.) in India as determined by indirect competitive-ELISA

Samples of the three grades of chilli pod (grades 1 to 3) were collected during surveys in 1998 and 1999 from the principal market yards and cold storage facilities of the major chilli-growing areas of Andhra Pradesh (AP), India. Chilli powders were collected from different supermarkets in Hyderabad, AP. They were analysed for aflatoxin B1 (AFB1) content by an indirect competitive ELISA. To avoid the influence of interfering substances present in chilli extracts, it was necessary to prepare the aflatoxin standards in methanol extracts of chillies free from aflatoxins. For nine representative samples there was good agreement between ELISA and HPLC estimations of AFB1 and the results suggested that the ELISA procedure adopted was dependable. Of the 182 chilli samples tested, 59% of the samples were contaminated with AFB1 and 18% contained the toxin at non-permissible levels. The highest AFB1 concentration of 969 microg/kg was found in one sample representing grade 3. Overall the maximum percentage of chilli pods showing AFB1 levels higher than 30 microg/kg (non-permissible levels) was in grade 3. Chilli pods stored in refrigerated rooms showed the lowest proportion of samples containing aflatoxin. Nearly 9% of the chilli powders sold in supermarkets contained non-permissible aflatoxin levels. This report highlights the importance of using grade 1 chilli pods to minimize aflatoxin contamination.

Production and characterization of monoclonal antibodies for aflatoxin B1

Hybridomas that secreted antibodies for aflatoxin B1 were selected using two immunization protocols referred to as A and B. Protocol A is a standard immunization method and resulted in the selection of only two clones that produced monoclonal antibodies against aflatoxin B1. In protocol B a unique immunization schedule which resulted in the generation of 10 hybridomas is described. Of the 10, one antibody was highly specific to B1, four antibodies reacted equally strongly with B1, G1 and weakly with B2. Another four reacted strongly with B1 and weakly with B2 and G1. One clone reacted equally strongly with B1, G1 and B2. Interestingly all the 10 antibodies showed little or no cross-reaction with G2.