Choose the correct answer from the options given below:

• (1) (A)-(III), (B)-(IV), (C)-(I), (D)-(II)
• (2) (A)-(III), (B)-(I), (C)-(IV), (D)-(II)
• (3) (A)-(III), (B)-(IV), (C)-(II), (D)-(I)
• (4) (A)-(II), (B)-(I), (C)-(IV), (D)-(III)

  The correct answer is option (2): (A)-(III), (B)-(I), (C)-(IV), (D)-(II).

  This matching question tests knowledge of immunological techniques in biotechnology, key for exams like GATE Life Sciences.

  Matching Explanations

  (A) Use of Hypoxanthine and Thymidine → (III) Hybridoma

  Hypoxanthine and thymidine form part of HAT medium (with aminopterin) used in hybridoma technology to select fused myeloma-spleen cells for monoclonal antibody production. Unfused myeloma cells lack HGPRT and die without the salvage pathway provided by HT, while unfused B cells don’t proliferate long-term.

  (B) Characterization of γ-Globulin Serum Proteins → (I) Immunoprecipitation

  Immunoprecipitation isolates and characterizes γ-globulins (immunoglobulins in serum) by forming antigen-antibody complexes that precipitate, often analyzed via electrophoresis or diffusion for purity and identity.

  (C) Formation of Chemiluminescent Product → (IV) ELISA

  Chemiluminescent ELISA uses HRP enzyme with luminol substrate; oxidation produces light-emitting intermediates detected by luminometer for high-sensitivity quantification.

  (D) Detection and Quantification of Number of Cells Producing Cytokines → (II) ELISPOT Assays

  ELISPOT captures cytokines secreted by individual cells on a coated membrane, forming visible spots per cytokine-producing cell for direct enumeration at single-cell resolution.

  Option Analysis

  Option	A-III	B-IV	C-I	D-II	B-I	C-IV	D-II	B-IV	C-II	D-I	A-II	B-I	C-IV	D-III	Correct?
  (1)	✓	✗	✗	✓											No
  (2)	✓	✓		✓	✓	✓	✓								Yes
  (3)	✓	✗						✓	✗	✓					No
  (4)	✗	✓			✓	✓					✓		✓	✗	No

  Option (2) uniquely matches all pairs correctly based on technique principles.​

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  Introduction to Key Immunological Techniques in GATE Life Sciences

  Hypoxanthine thymidine hybridoma ELISPOT ELISA immunoprecipitation techniques are essential for matching questions in competitive exams like GATE Life Sciences, testing biotech and immunology knowledge. This article solves Q.71 with detailed explanations.​

  HAT Medium in Hybridoma Technology

  Hybridoma production uses HAT (hypoxanthine-aminopterin-thymidine) medium where hypoxanthine and thymidine enable salvage pathway nucleotide synthesis in fused cells only.

  Immunoprecipitation for γ-Globulin Analysis

  Immunoprecipitation characterizes serum γ-globulins by precipitating immune complexes, vital for antibody studies.

  Chemiluminescent Detection in ELISA

  ELISA employs chemiluminescence via luminol-HRP reaction for sensitive signal amplification in immunoassays.

  ELISPOT for Cytokine-Secreting Cells

  ELISPOT quantifies cytokine-producing cells by spotting secreted factors, outperforming bulk ELISA for frequency analysis.

  Exam Tips for Matching Questions

  Practice linking techniques to principles: HAT for selection, IP for precipitation, chemiluminescence for ELISA, spots for ELISPOT.​