Question

The technique for the early detection of a disease based on the principle of antigen-antibody interaction is:

• A. RNAi
• B. EST
• C. PCR
• D. ELISA

Hint:

ELISA works on the principle of antigen-antibody interaction and is a sensitive, early-detection tool in clinical diagnostics.

Answer 1

The Correct Option is D

The correct answer is ELISA

Understanding Techniques for Early Disease Detection

The question asks which technique is used for the early detection of a disease based on the principle of antigen-antibody interaction. Antigen-antibody interactions are central to immunological diagnostic methods, where specific antibodies bind to target antigens to identify the presence of a disease.

Identifying the Correct Technique

Among the listed options, ELISA (Enzyme-Linked Immunosorbent Assay) is the technique that relies on antigen-antibody interactions for detecting diseases. It is widely used for early diagnosis of various conditions, such as infections and autoimmune disorders.

• ELISA: Enzyme-Linked Immunosorbent Assay is a diagnostic tool that detects antigens (e.g., pathogen proteins) or antibodies in a sample by using specific antigen-antibody binding. An enzyme-linked reaction produces a measurable signal, typically a color change, to indicate the presence of the target. ELISA is used for diseases like HIV, hepatitis, and COVID-19 due to its sensitivity and specificity.
• RNAi: RNA interference is a biological process where RNA molecules inhibit gene expression, typically used in research to silence specific genes. It is not a diagnostic technique and does not involve antigen-antibody interactions.
• EST: Expressed Sequence Tag is a short sequence of DNA derived from cDNA, used in genomics to identify gene transcripts. It is a tool for gene discovery, not a diagnostic method or related to antigen-antibody interactions.
• PCR: Polymerase Chain Reaction amplifies DNA segments for detection of genetic material, such as pathogen DNA or RNA. While PCR is used for disease diagnosis (e.g., detecting SARS-CoV-2), it targets nucleic acids, not antigen-antibody interactions.

Based on the principle of antigen-antibody interaction, ELISA is the correct technique for early disease detection.

Comparing Diagnostic Techniques

Here is a comparison of the techniques mentioned in the options:

Technique	Primary Contribution Relevant to Question Context
ELISA	Detects diseases using antigen-antibody interactions; widely used for early diagnosis.
RNAi	Silences genes via RNA; used in research, not diagnostics.
EST	Identifies gene transcripts in genomics; not a diagnostic tool.
PCR	Amplifies DNA for genetic detection; does not use antigen-antibody interactions.

Therefore, ELISA is the technique for early disease detection based on antigen-antibody interactions.

Revision Table: Key Techniques in Molecular Biology and Diagnostics

Technique	Associated Field/Use	Significance
ELISA	Immunology/Diagnostics	Detects antigens/antibodies for diseases like HIV, hepatitis.
RNAi	Molecular Biology/Research	Silences genes to study function or develop therapies.
EST	Genomics/Research	Identifies expressed genes for genomic studies.
PCR	Molecular Biology/Diagnostics	Amplifies DNA for detecting pathogens or genetic markers.

Additional Information on ELISA and Antigen-Antibody Interactions

ELISA, developed in the 1970s, revolutionized medical diagnostics by leveraging the specificity of antigen-antibody interactions. The technique involves immobilizing an antigen or antibody on a solid surface, adding a sample, and using enzyme-linked antibodies to produce a detectable signal. Variants like sandwich, direct, and indirect ELISA allow flexibility in detecting different targets. Its applications extend beyond infectious diseases to include hormone levels, allergies, and cancer markers. The Mahabharata period, while unrelated to modern diagnostics, reflects early Indian knowledge of health and medicine, as seen in references to healing practices in the epic. ELISA’s role in modern medicine underscores the importance of immunological techniques in early disease detection, ensuring timely intervention and improved health outcomes.