Q.66 Which of the following are types of ELISA?
A. Competitive
B. Discontinous
C. Indirect
D. Sandwich
Choose the correct answer from the options given below:
- A, B, C, D
- A, B, C only
- A, D only
- A, C, D only
Correct Answer: A, C, D only
ELISA encompasses competitive, indirect, and sandwich formats as standard types, while “discontinuous” is not a recognized category.
Option Analysis
A. Competitive
True. Competitive ELISA involves sample antigen competing with immobilized antigen for limited antibody binding, producing an inverse signal proportional to analyte concentration.
B. Discontinuous
False. No standard ELISA classification uses “discontinuous”; this term does not appear in immunology literature for assay types.
C. Indirect
True. Indirect ELISA employs an unlabeled primary antibody followed by enzyme-linked secondary antibody, amplifying signal through multiple secondary bindings.
D. Sandwich
True. Sandwich ELISA captures antigen between a plate-bound capture antibody and a labeled detection antibody, offering high specificity for complex samples.
Introduction to ELISA Techniques
Types of ELISA like competitive, indirect, and sandwich dominate biotechnology exams such as GATE Life Sciences, enabling precise antigen/antibody detection. This analysis clarifies which options qualify as true ELISA variants, aligning with your molecular biology exam preparation.
Competitive ELISA Mechanism
In competitive ELISA, labeled antigen competes with sample analyte for antibody sites; higher analyte reduces signal. Ideal for small molecules or haptens due to its flexibility.
Indirect ELISA Advantages
Primary antibody binds antigen, followed by enzyme-conjugated secondary antibody for signal boost. Versatile for antibody detection in serum, though prone to cross-reactivity.
Sandwich ELISA Specificity
Capture antibody coats the plate, trapping antigen; detection antibody completes the “sandwich.” Excels in cytokine quantification from crude samples.
Why Discontinuous Fails
“Discontinuous” lacks recognition among four canonical ELISA types (direct, indirect, sandwich, competitive); possibly confuses with unrelated gel electrophoresis terms.
Option ELISA Type Valid? Primary Use A Competitive Yes Small molecules B Discontinuous No Not a type C Indirect Yes Antibody detection D Sandwich Yes Complex samples
