Question

A college student has been called into the student health office because she tested positive for HIV on the enzyme-linked immunosorbent assay (ELISA). The student asks, "What is this Western blot assay going to tell you?" The best response by the health care provider is:_______________.

Answer 1

Answer:

- Basically the western blot assay is an assay that targeted the presence of a specific antibodies to a specific antigen.

Step-by-step explanation:

The western blot assay is a technique which makes use of its specific characteristics of proteins to analyse and identify a particular protein in mixture of different protein extracts.

it analysis depends

→on the molecular sizes of the protein under investigation.

→on the transfer to a solid support, and

→Tracing and marking of protein under investigation by visualisation of corresponding synthetic antibodies which bind with antigen.

The procedure involves denaturation of protein to breakdown the 3-dimensional proteins structure,, which leads to loss of forms and inability to interfere with the analytic process.

This is followed by separation of the proteins into their sizes and therefore forms by Gel Electrophoresis .Specific primary antibody to bind with the specific antigen is designed. The electrophoresis is washed in a solution which contains antibody solution,and the results is transferred to a membrane, with which gives band for each specific protein.

Secondary antibody is introduced into this solution to bind with the primary antibody( the unbound antibody),and its tracing is detected to determine the intended protein. This tracing should appear as single band of antibody-antigen complex.Since an antibody must bind with a specific protein it was designed for.

Step-by-step explanation:

Answer 2

Answer: For detection and confirmation of HIV antibodies in blood samples.

Explanation: As the name implies ELISA( Enzyme-linked immunosorbent assay) is the first test widely used for determining the presence of HIV in a person's serum because of its high sensitivity. In an ELISA, a person's serum is diluted 400 times and applied to a plate to which HIV antigens are attached. If antibodies to HIV are present in the serum, they may bind to these HIV antigens. The plate is then washed to remove all other components of the serum. A specially prepared "secondary antibody" (an antibody that binds to other antibodies) is then applied to the plate, followed by another wash. This secondary antibody is chemically linked in advance to an enzyme.

Thus, the plate will contain enzyme in proportion to the amount of secondary antibody bound to the plate. A substrate for the enzyme is applied, and catalysis by the enzyme leads to a change in color or fluorescence. ELISA results are reported as a number; the most controversial aspect of this test is determining the "cut-off" point between a positive and a negative result. A cut-off point may be determined by comparing it with a known standard. Unknown samples that generate a stronger signal than the known or control sample or are called "positive" while those that generate weaker signal are "negative".