The ImmunoComb® is a diagnostic test that looks for specific Antibodies in the blood. Antibodies are components of the immune system that fights foreign entities entering the body. These antibodies can also serve as diagnostic markers that indicate previous exposure to specific pathogen, a disease causing agent. Depending on the combined information on the amount of antibodies, clinical signs and vaccination history the result can indicate vaccine protection, recent infection or past infection.
The ImmunoComb assay is similar in principal to what is called ELISA, an Enzyme Linked Immuno-Sorbent Assay. Yet, in much simpler to operate format.
The ImmunoComb kits contain all the necessary reagents for developing the test in the Vet office, without the need for any equipment required for classic ELISA like special dispensers, automatic washer or electronic reader.
The ImmunoComb is based on two components, the Comb and the Plate.
The Comb's 12 teeth are activated with specific antigens localized to dots on the Comb. Antigens are "building blocks" elements of the tested disease agents.
The plate contains 6 wells filled with different formulated reagents that enable the development of the assay. These reagents have common functions as in classic ELISA, yet as being contained within the development plate, enable simple equipment's free assay development.
How the ImmunoComb® Assay operated and what's happen inside?
The first step of the assay is to add a sample into well A in the plate. The Comb is then inserted into this well. If a single patient is tested, one tooth can be cut out of the 12 teeth Comb. The tooth, partial Comb or the complete comb (depending on the number of patients) is now incubated in well A for several minutes subject to the tested disease and the kit in use.
During the incubation, specific antibodies, if present in the sample, binds to the deposited Antigens on the Comb. This binding is unique like a key and a keyhole. None specific antibodies will bind weakly and will be removed on next steps.
On the second step, the Comb is transferred from well A to Well B. During the incubation in well B, a special wash solution remove the none specific bound antibodies leaving the specific antibodies (if where present in the sample) bound to the Antigen on the Comb.
Next, the Comb is transferred from Well B to Well C. In this well, there is a "Conjugate" a secondary Antibody with chemically tied enzyme. This Conjugate recognize natural antibodies specific to the tested animal. During the incubation in well C, the Conjugates will bind to the Antibodies that remained bound to the Antigens on the Comb.
Imagine a Human tower competition where the father holds on his shoulders the older boy that holds on his shoulders the younger sister. The father is like the Antigen, the boy is the specific antibodies and the young sister is the conjugate.
In the next two steps the Comb is moved to 2 additional wash wells, similar to well B, remove none specific bound materials.
In the last step, the Comb is moved to a substrate solution for short incubation. The substrate formulation contains a colorless chemical that the Conjugate from Well C digest. The digestion carried out by the enzymatic part of the conjugate, creates a dark gray product. This digested colored product will be deposited on the Comb only if the Conjugate is present. The conjugate's digested products will be localized to the Antigens dots on the Comb only if there were specific antibodies in the blood sample.
In analogy to the Human tower competition, the wining family is the one that her younger kid pull a flag from a tall pole. Only a complete tower will enable to reach this height. Therefore, waving the flag, like the colored reaction in the ImmunoComb, indicates that all the essential previous steps took place.
Indirectly, a flag means that a boy must be present in the tower and a gray spot on the ImmunoComb means that specific antibodies to a certain disease agent must be present; hence the patient was exposed to the disease agent.