Cross-reactivity study procedure

As mentioned earlier, the purpose of this review is not to detail the actual methods used for tissue cross-reactivity studies but rather to highlight the many important factors that must be taken under consideration during the conduct, evaluation, and regulatory review and of the study. Specific details for tissue collection, generation of control materials, and staining procedures themselves are readily available in the literature. 

For monoclonal antibodies, the immunological properties of the antibody should be described in detail, including its antigenic specificity, complement binding, and any unintentional reactivity and/or cytotoxicity towards human tissues distinct from the intended target. Such cross-reactivity studies should be carried out by appropriate immunohistochemical procedures using a range of human tissues. 

A third collaborative study (10) was conducted examining the Immuno Dot Screen Cup (Afla-20, IDS Cup), a test kit containing antibodies with considerable cross reactivity with aflatoxins B2 and G,. The manufacturer s procedure was also modified to increase the reliability of detection at 20 ng/g total aflatoxins, and to broaden the applicability to include peanut butter samples. 

Immunofluorescent detection of TS protein was done with the use of monoclonal antibodies, developed by in vivo immunization of Balb/c mice with homogeneous recombinant rat hepatoma TS protein as an antigen. The specific anti-rat TS antibodies recognized also T. spiralis TS, as indicated by cross-reactivity on Western blot. Localization of the enzyme was based on analysis of pictures collected by confocal microscopy. Two types of T spiralis muscle larvae preparations were studied muscle larvae isolated from mouse muscles by a procedure destroying nurse cells and muscle larvae remaining in nurse cells, isolated as an intact nurse cell preparation. 

Highly purified h-TSH and b-TSH showed no cross reactivity by gel diffusion methods and radioimmunological precipitation techniques (U2). However, in several bioassay procedures limited cross reactivity has been shown between anti-b-TSH antibodies (L4, M9, U2) and human TSH. A radioimmune assay described by Lemarchand-Beraud (L2) is based on the use of anti-b-TSH antibodies developed in rabbits. Recently cross reactivity has been reported between h-TSH and antibodies to porcine TSH (F9). Radioimmunoassay procedures were used in these studies. It would appear that there may be two groups of antigenic sites on human TSH, one specific and one shared in common with b-TSH and p-TSH. 

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