The heart of IMMULITE 1000 is the proprietary Test Unit, which offers a breakthrough in automated bead washing. The Test Unit, containing an assay-specific coated bead, serves as the reaction vessel for all sample processing. Spinning the Test Unit at high speed efficiently expels fluid into the integral sump chamber. The tube design allows for multiple discrete washes within seconds, ensuring excellent separation of unbound material for highly sensitive assays. IMMULITE 1000's unique wash technique produces extremely low and consistent nonspecific binding, which is critical for assay performance.

Sustained Chemiluminescence
IMMULITE 1000's enzyme-amplified chemiluminescence translates into lower detection limits compared to conventional "flash" chemiluminescence. Rather than one or two photons per immuno-binding event, thousands of photons are emitted per binding event with the IMMULITE 1000 reaction. Automatic light signal attenuation effectively broadens the range of luminometer readings 100-fold. The sustained signal produced by the enzyme-enhanced chemistry allows multiple readings to be taken for more precise measurements.

Bet v 1-Specific IMMULITE® inhibitions:  It was noticed that most patients, except #2220029, displayed mild oral allergy syndrome (OAS) symptoms aÑ–er consumption of cashew nut and hazelnut, next to the more severe gastrointestinal complaints. As all children are birch pollen-sensitised we speculated that the observed clinical symptoms as well as the measured IMMULITE® sIgEinhibitions in some patients might be explained by a secondary (crossreactive) reaction on Bet v 1-homologues in cashew nut, hazelnut and peanut. Нerefore, an inhibition assay with nBet v 1 protein was performed on 4 of the 5 patients (for 3330002 not enough serum was leÑ–).

The Immulite system uses enzyme-amplified chemiluminescent technology. The mechanism involves hydrolysis of a stable chemiluminescent substrate, adamantyl dioxetane phosphate, through the action of the enzyme alkaline phosphatase. This process results in the constant production of the unstable adamantly dioxetane anion. Constant production of the anion gives rise to sustained emission of light that provides a longer window for more numerous and precise readings than can be performed with other luminescent methods, which rely on their characteristic “flash” of light. The emitted light is quantified by use of the Immulite luminometer.

The Immulite LH assay, a solid-phase, two-site IRMA, is an example of this system. The solid phase consists of a polystyrene bead that is coated with a polyclonal antibody directed against LH. The bead is sealed into an Immulite test unit; the LH standard or serum sample and the monoclonal antibody conjugated to alkaline phosphatase are then added simultaneously. During a 30-minute incubation period at 37ºC, LH is bound to the polyclonal antibody coating the bead and to the monoclonal antibody–enzyme conjugate in the form of a sandwich complex. After unbound antibody is removed by a wash and centrifugation, the amount of bound complex, which is directly proportional to the LH (standard or sample), is quantified by use of the chemiluminescent substrate described earlier. The new Immulite system (Immulite 1000) is used by many laboratories and permits the simultaneous assay of more than 10 different hormones.

Media Contact: 
Allison Grey 
Journal Manager 
Journal of Clinical chemistry and Laboratory Medicne
|Email: jcclm@molecularbiol.com