Monoclonal antibodies cross-reactivity

Table II. Tetryl Monoclonal Antibody Cross-Reactivity...

To improve the specific response against microcystin immimoconjugates, synthetic lipopeptides were used as adjuvants and were found to invoke a greater immune response than the use of classical adjuvants such as Freunds adjuvant. However, an ELISA for the detection of free microcystin was not developed using these antibodies. Cross-reactivities of various microcystin variants and nodn-larin with monoclonal antibodies have been found affecting to the specificity of these antibodies for the recognition of the mentioned toxins. The number of purified microcystin variants that have been tested by ELISA using monoclonal antibodies shows marked differences between methods. 

A specific antibody is desirable because it enables an IA to be performed with limited or no sample clean-up. For reagent-excess methods, it is very important to choose specific antibodies. Cross-reactivity of polyclonal antiserum from each blood collection or each clone of monoclonal antibodies is tested against known metabolites, drug degradants, concomitant drugs, and the protein carrier... 

A two-site immunometric assay of undecapeptide substance P (SP) has been developed. This assay is based on the use of two different antibodies specifically directed against the N- and C-terminal parts of the peptide (95). Affinity-purified polyclonal antibodies raised against the six amino-terminal residues of the molecule were used as capture antibodies. A monoclonal antibody directed against the carboxy terminal part of substance P (SP), covalently coupled to the enzyme acetylcholinesterase, was used as the tracer antibody. The assay is very sensitive, having a detection limit close to 3 pg/mL. The assay is fiiUy specific for SP because cross-reactivity coefficients between 0.01% were observed with other tachykinins, SP derivatives, and SP fragments. The assay can be used to measure the SP content of rat brain extracts. 

A wide selection of monoclonal and polyclonal anti-Ca -ATPase antibodies have become available in recent years. Studies with these antibodies defined the localization of Ca " -ATPase in the sarcoplasmic reticulum of developing and mature skeletal muscles [60,262-270] and established a pattern of cross reactivity with various Ca -ATPase isoenzymes in the sarco(endo)plasmic reticulum [270-286] and in the plasma membrane [284,287-290] of skeletal, cardiac and smooth muscles. Antibodies have also proved useful in the quantitation of Ca -ATPase, both in muscles of diverse fiber types [291-294] and in COS-1 cells transfected with Ca -ATPase cDNA [97,103,126,127,129,215],... 

Table 2 Cross-reactivity of racemic ractopamine and ractopamine glucuronide metabolites to a monoclonal antibody developed against racemic ractopamine...

Donohue-Rolfe, Arthur, David W.K. Acheson, Anne V. Kane, and Gerald T. Keusch. "Purification of Shiga Toxin and Shiga-Like Toxins I and II by Receptor Analog Affinity Chromatography with Immobilized PI Glycoprotein and Production of Cross-Reactive Monoclonal Antibodies." Infection and Immunity 57 (December 1989) 3888-893. 

Lymphocytes, the effector cells of the acquired immune system, include morphologically indistinguishable T and B cells, the former divided into CD4+ T helper cells and CD8+ cytotoxic T cells. Since the functions of those cell subsets differ so drastically, it became important to develop tools to distinguish them from each other. Efforts to identify cell subsets according to their expression of different surface antigens have been successful, including various Cluster of Determination (CD) markers (Table 23.1). In addition, cross-reactive monoclonal antibodies, and subsequently developed species-specific polyclonal and monoclonal antibodies towards the major histocompatibility complex (MHC) have been used to label cells in circulation and in tissue sections (Table 23.1). 

Preclinical studies should address the potential toxicity due to inappropriate release of the conjugated toxin. Preclinical toxicology of monoclonal antibodies may not require extensive animal studies but should be examined for cross-reactivity with antigenic epitopes present on normal cells in vitro and for the presence of human or rodent vimses. Early clinical trial should involve biodistribution studies with radiolabelled material. 

Another indicator that the SEs share similar structures is evidenced by cross-reactivity and neutralization with antibodies. Several years ago, when there were less SEs known, these molecules were considered serologically distinct entities as determined by antisera and relatively insensitive immunodiffusion assays. However, subsequent studies employing a more sensitive technique (ELISA) with polyclonal and monoclonal antibodies clearly reveal that common epitopes do indeed exist between these toxins. 

Other anticoccidials for which immunoassays have been developed include the polyethers salinomycin and lasalocid, and the quinazoline drug halofuginone. Concern over the potential toxicity of salinomycin has led to development of two competitive ELISAs for detecting and measuring salinomycin residues in poultry tissues. In the first ELISA (96), 16 monoclonal antibodies were prepared and evaluated for their ability to produce a rapid and low-cost screening procedure for residues of salinomycin in poultry liver. In the second (97), the antibodies produced showed cross-reactivity with narasin but not with lasalocid, madura-... 

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