A sensitive and specific enzyme immunoassay for cyclomaltoheptaose and some derivatives

A monoclonal antibody to cyclomaltoheptaose (beta-cyclodextrin): Characterization and use for immunoassay of beta-cyclodextrin and its derivatives

Cyclomaltoheptaose (beta-cyclodextrin, beta-CD) is a promising compound for application in various industrial fields because of its ability to entrap various compounds into its hydrophobic cavity. A monoclonal antibody (A7) to beta-CD was generated by using a conjugate of glucosaminylmaltosyl-beta-CD and bovine serum albumin as an antigen. The A7 monoclonal antibody was IgM/kappa and reacted with beta-CD with high specificity. The epitope recognized by the A7 monoclonal antibody seemed to be located on the secondary hydroxyl groups of the rim side of the beta-CD molecule. The dissociation constant of the complex of beta-CD and the immobilized A7 monoclonal antibody was determined to be 1.2 x 10(-4) M. A competitive ELISA using the A7 monoclonal antibody enabled determination of beta-CD and its derivatives with a detection limit of 0.05 muM. This immunoassay was useful to determine beta-CD in biological fluids such as human plasma and urine after appropriate pretreatment of the samples.

A sensitive and specific enzyme immunoassay for the detection of methyl ether derivatives of cyclomaltoheptaose

We have raised antibodies against two methylated derivatives of beta-CD, heptakis(2,6-di-O-methyl)cyclomaltoheptaose (Dimeb) and heptakis(2,3,6-tri-O-methyl)cyclomaltoheptaose (Trimeb). These antibodies were used to develop two specific and sensitive enzyme immunoassays, presenting a detection limit close to 500 and 30 pg/mL for Trimeb and Dimeb, respectively. Cross reactivities of different linear and cyclic maltooligosaccharides were investigated, demonstrating a high specificity against the structural features of the secondary hydroxyls rim. Several commercial Dimeb samples, containing different mixtures of partially methylated beta-cyclodextrin derivatives including RAMEB, which contains only a few amount of pure Dimeb, could be easily evaluated by the Dimeb immunoassay. Both of these assays have been shown to allow accurate measurement in plasma and urine, thus appearing as useful tools for further applications in biological material.

Pharmacological in vitro evaluation of new substance P-cyclodextrin derivatives designed to drug targeting towards NK1-receptor bearing cells

Some biological properties of new bifunctional conjugates designed for drug targeting were evaluated through in vitro experiments. Eight peptidylcyclodextrin compounds were used, which correspond to modified beta- or gamma-cyclodextrin (CD) grafted on neuropeptide substance P (SP) or a shorter derivative (SP(4-11)). Using anti-SP and anti-CD antibodies as molecular probes, we showed that the main structural features of the two moieties of these adducts were preserved. Binding experiments, using CHO cells expressing the human SP-specific NK1 receptor, demonstrated the functionality of all peptidylcyclodextrin derivatives, which exhibited IC50 values in a 10(-9)-10(-7) M range. All compounds were able to induce a pharmacological response, triggering phosphatidylinositol turnover with EC50 values in the same range as the natural ligand. Moreover, autoradiography analysis of rat spinal corn sections proved that [125I]SP binding was dose-dependently displaced by one selected compound (a gamma-CD-SP), showing a similar affinity of this adduct for the rat neurokinin 1 receptor. Our observations demonstrate that these peptidylcyclodextrins efficiently target NK1 receptor-expressing cells.

Differential modulation of alpha, beta and gamma enolase isoforms in regenerating mouse skeletal muscle

Nothing is known about the expression of the glycolytic enzyme enolase in skeletal muscle alterations such as myofiber degeneration and regeneration. Enolase is a dimeric enzyme which exhibits cell type specific isoforms. The embryonic form, alphaalpha, remains expressed in most adult tissues, whereas a transition towards specific isoforms occurs during ontogenesis in two cell types with high energy requirements: alphagamma and gammagamma in neurons, alphabeta and betabeta in striated muscle cells. During murine myogenesis, beta enolase transcripts are detected early in the forming muscles, and the beta gene is further upregulated at specific stages of muscle development. The alpha and beta subunits exhibit characteristic developmental microheterogeneity patterns. High levels of beta enolase subunits characterize the glycolytic fast-twitch fibers of adult muscles. We have investigated the expression of enolase subunits in a mouse experimental model of muscle regeneration. Following a single intramuscular injection of the necrotic agent cardiotoxin, we observed a rapid decrease in the level of the major muscle enolase subunit beta, accounting for the drop in total enolase activity that correlated with the degeneration of myofibers. Concomitant with the regeneration of new fibers, beta subunit levels began to increase, reaching normal values by 30 days after injury. Changes in the embryonic and ubiquitous subunit, alpha, mimicked those occurring during development by two aspects: modifications in electrophoretic variants and redistribution between soluble and insoluble compartments of muscle extracts. Imunocytochemical analyses of alpha and beta enolase subunits first revealed a homogeneous labeling within myofibers. Striations characteristic of normal adult muscle tissue were visible again by day 14 after injury. A perinuclear alpha and beta immunoreactivity was often observed in regenerating myofibers but its functional significance remains to be elucidated. Double labeling experiments with anti-gamma enolase and FITC-alpha bungarotoxin allowed us to follow the neuromuscular junction remodeling that occurs during muscle regeneration despite the absence of nerve injury.

Pharmacokinetic analysis of 6-monoamino-beta-cyclodextrin after intravenous or oral administration to rats using a specific enzyme immunoassay

We have developed a highly sensitive enzyme immunoassay for 6-monoamino-beta-CD (mono(6-amino-6-deoxy)cyclomaltoheptaose) and its parent compound (beta-CD) with a detection limit in the 100 pg/mL range. The polyclonal antibodies obtained are highly specific for the beta-cyclodextrin core and do not recognize other cyclic cyclodextrins (i.e., alpha- and gamma-CD) or linear analogues. This enzyme immunoassay can be used to quantify 6-monoamino-beta-CD in rat urine and plasma. Using this immunoassay, we have evaluated the main pharmacokinetic parameters of 6-monoamino-beta-CD after iv administration to the rat of a 25 mg/kg dose. Since this method is strictly specific to the native beta-CD form, we have demonstrated that the molecule rapidly disappeared from plasma but is probably distributed in the tissues. The urinary route appears as the predominant way of elimination since almost all the administered drug is recovered in urine. Finally, analysis of the same molecule after oral administration to the rat (25 mg/kg) demonstrates low plasma levels and that about 1% of the administered dose is excreted in urine. These experiments demonstrate the high stability of the beta-CD core irrespective of the method of administration. This immunological method could provide relevant information on the fate of beta-CD and some derivatives for drug delivery using different modes of administration (oral, parenteral, transmucosal, or dermal).