Kimia Klinik: Imunoassay

Summary

In this video, the topic of immunoassays is discussed, focusing on the technique used to detect specific antigen-antibody interactions. The video covers key concepts such as antibodies, haptens, and labeling techniques. It explains how immunoassays, including qualitative tests like Western Blot and quantitative tests like ELISA, are used in clinical diagnostics. The video highlights the importance of specific antibody-antigen interactions and the methods for detecting them, such as enzyme-linked assays. Practical applications of these techniques, such as HIV detection and pregnancy testing, are also explored, showcasing their broad use in clinical labs.

Takeaways

• 😀 Immunoassay is an analytical technique that uses the immune system's specific binding between antigens and antibodies for detection.
• 😀 Immunoassay can be qualitative or quantitative, and it's widely applied in clinical diagnosis.
• 😀 Antibodies are compounds produced by the immune system to fight foreign substances. There are monoclonal and polyclonal antibodies, with monoclonal recognizing a single antigen and polyclonal recognizing multiple antigens.
• 😀 A hapten is a small foreign molecule that can activate the immune system when bound to a larger molecule like a protein.
• 😀 The term 'label' in immunoassays refers to a compound attached to aid in the detection or reaction process.
• 😀 The binding between antigen and antibody can be influenced by ionic charges, such as cations or anions, and polymer effects that speed up immune complex formation.
• 😀 Western Blot is used in qualitative analysis and involves transferring proteins onto a membrane for detection using labeled antibodies.
• 😀 In Western Blot, detection can be done using radioactive or enzyme labels, with the direct method using enzyme-labeled antibodies and indirect method using secondary labeled antibodies.
• 😀 ELISA (Enzyme-Linked Immunosorbent Assay) is commonly used for quantitative analysis, detecting and counting specific antigens in samples.
• 😀 There are three types of ELISA: Direct, Indirect, and Sandwich. Sandwich ELISA is the most sensitive and often used for detecting diseases like pregnancy and HbA1c.
• 😀 ELISA is widely used in clinical laboratories for detecting various antigens causing diseases, making it a versatile and reliable tool for clinical diagnostics.

Q & A

What is immunoassay?

Immunoassay is an analytical technique that uses the body's immune system to form specific binding between an antigen and antibody. This analysis can be qualitative or quantitative and is widely used for diagnosing patients.

What are antibodies and what is their role in immunoassays?

Antibodies are compounds secreted by B-cells to combat foreign substances entering the body. In immunoassays, antibodies specifically recognize antigens, forming a complex that can be analyzed. There are two main types of antibodies: monoclonal and polyclonal.

What is the difference between monoclonal and polyclonal antibodies?

Monoclonal antibodies recognize only one type of epitope on an antigen, while polyclonal antibodies can recognize multiple epitopes on the same or different antigens.

What are haptens, and how do they work in immunoassays?

Haptens are small foreign substances that can activate the immune system when bound to a larger molecule like a protein. Though they are small, their binding with a larger molecule can trigger an immune response.

What is the role of 'labels' in immunoassays?

In immunoassays, a label refers to the attachment of another compound that helps detect or react with the antigen-antibody complex, assisting in the detection process.

What types of bonds can form between antigens and antibodies in immunoassays?

The types of bonds between antigens and antibodies can include van der Waals, hydrophobic, and ionic bonds. These bonds affect the formation of immune complexes.

What is Western Blot, and how is it used in immunoassays?

Western Blot is a qualitative immunoassay used to detect proteins. After proteins are separated by SDS-PAGE, they are transferred to a membrane where specific antibodies are added to detect the presence of antigens. Detection can be done through radioactive or enzymatic methods.

How does the detection process differ between direct and indirect methods in immunoassays?

In the direct method, the antibody added is labeled with an enzyme to detect antigen presence. In the indirect method, a secondary antibody labeled with an enzyme is used to detect the primary antibody bound to the antigen.

What are the three main types of ELISA?

The three main types of ELISA are direct, indirect, and sandwich ELISA. Each method differs in how the antibodies and antigens are added, as well as how detection is carried out.

What is the advantage of sandwich ELISA over other types?

Sandwich ELISA has higher sensitivity and specificity, making it ideal for detecting antigens even in impure samples. This method is widely used in clinical labs for detecting various antigens, including in tests for diseases like HIV.