Immunology (GATE)

HAT (hypoxanthine-aminopterin-thymidine) selection technique is used for generating monoclonal antibodies. Briefly, HAT selection implies the use of HAT medium. Unfused myeloma (HGPRT negative) cells are killed by aminopterin which interferes with the conversion of tetrahydrofoliate to dihydrofoliate and prevents a series of carbon transfers. Unfused normal spleen cells die because they are not able to grow for long periods. Thus, only the fused hybridoma cells survive on this medium.

Basophils are involved in allergic reactions and release histamine (for triggering inflammation) and heparin (for preventing blood clotting).

Eosinophils accumulate in the nasal mucosa during allergic rhinitis. Accumulation of eosinophils in the nasal mucosa is considered a major diagnostic criterion for allergic rhinitis (nasal allergies).

Cytotoxic T-cells cause lysis of virally infected cells, tumour cells and allografts.

Alkaline phosphatase, lysozyme, NADPH oxidase, collagenase, lactoferrin and cathelicidin are contained in the specific granules (or secondary granules) of neutrophils.

In classical complement pathway, C4b2b complex functions as C3 convertase. It cleaves C3 into C3a and C3b.

The classical complement pathway typically requires antigen-antibody complexes (immune complexes) for activation (specific immune response).

C7 protein is associated with a transition of the complex from a hydrophilic to hydrophobic state and allows complex to insert itself into the lipid bilayer.

This is incorrect. Presence of lymphocytes in tumours is often associated with better clinical outcomes.

Macrophages present in the linings of spleen are called medullary sinusoids. 

Ouchterlony test is known as double diffusion in two dimensions. Antigens and antibodies are kept in adjacent wells. They diffuse towards each other, forming a zone of precipitation.

Radioimmunoassay (RIA) is a very sensitive in vitro assay technique used to measure the concentration of antigens. It can detect antigens up to picogram level.

Granzymes function as serine proteases. They supposedly bring about protein lysis and DNA damage.

Alpha-2-macroglobulin inhibits coagulation by inhibiting thrombin. It also inhibits fibrinolysis by inhibiting plasmin.

Mannose binding protein is a major basic protein and is localised in the core of the granules. In the pre-immune host, its function appears to be pattern recognition in the first line of defense.