Immunosero Quiz 2

Immunologic Reactions

Reactions involving antigens and antibodies, classified into primary, secondary, and tertiary.

Primary Phase

The stage of immunologic reactions where antigens and antibodies combine, typically non-visible.

Secondary Phase

The stage where visible antigen-antibody reactions occur, such as agglutination or precipitation.

Tertiary Phase

The stage where biological effects such as phagocytosis and opsonization are observable.

Direct

The test that detects a known antigen on the specimen using a known anti-sera.

Indirect

The test that detects unknown antibodies on the patient serum using a known commercial antigen.

Precipitation Test

A test that measures the formation of a visible precipitate in a fluid medium when antigen and antibody react.

Nephelometry

A technique measuring scattered light to determine the concentration of insoluble complexes formed by antigen-antibody reactions.

Turbidimetry

A method that measures the decrease in light intensity in a solution of antigen-antibody complexes.

The _____ the light intensity, the ____ the concentration of complexes.

Lower, Higher

• Size of particles

• Temperature

• Gel viscosity and hydration

Factors that affects Immunodiffusion:

Radial Immunodiffusion (RID)

A single diffusion, double dimension immunodiffusion technique.

Fahey and Mckelvey

• The kinetic method of RID.

• read after 18 hours.

• multiple measurements are also performed.

Mancini

• The Endpoint method of RID.

• IgG is read at 24-48 hrs.

• IgM is read at 50-72 hrs.

Oudin test

The most simple single diffusion, single dimension immunodiffusion technique.

Antigen diffuse towards the agar gel, no electrical current needed.

Result is a Precipitin Line

Ouchterlony test

A double, diffusion, double dimension immunodiffusion technique.

widely used for comparing antigens.

Identity

they will form a smooth arc in an Ouchterlony test.

Partial Identity

A spur- shaped line appears in the ouchterlony test.

Non-Identity

A crossing lines form in the ouchterlony test.

Oakley and Futhrope

A double (linear) diffusion, single dimension Ouchterlony test method.

Prozone phenomenon

A condition where excess antibodies prevent precipitation, leading to unbound antibodies being detectable in the supernatant.

Serum Dilution

Remedy for Prozone phenomenon

Zone of Equivalence

The optimal mixing point of antigen and antibody where maximal precipitation occurs.

Postzone phenomenon

Occurs when excess antigens inhibit precipitation, leading to unbound antigens detectable in the supernatant.

Repeat the test after a week to give time for the antigen to reproduce.

Remedy for Postzone phenomenon

Immunoelectrophoresis

A technique combining electrophoresis with immunodiffusion to analyze serum proteins.

Rocket electrophoresis

One dimension, Electroimmunodiffusion technique.

It is a quick and simple in determining the concentration of specific antigens in a unknown sample.

The height of rocket is _______ to the concentration of antigen.

Directly proportional

Counterimmunoelectrophoresis (CIE)

Modification of Ouchterlony

Antigen and antibody puts onto the wells and Antibody migrates towards the cathode (-) and antigen to anode (+)

Grading of Agglutination

Smooth suspension

0

Grading of Agglutination

Barely discernible clumps

1+

Grading of Agglutination

numerous small clumps

2+

Grading of Agglutination

Several large clumps

3+

Grading of Agglutination

One solid clump

4+

Complement Fixation Test

A test that uses complement proteins to detect the presence of specific antibodies in a sample.

No Agglutination

The positive result for agglutination inhibition.

Agglutination

The negative result for Agglutination inhibition.

Indirect Antiglobulin Tests (IAT)

Identifies reactions of reagent RBC antigen with specific antibody when the reaction occurs in vitro.

Direct Antiglobulin test (DAT)

Detects specific antibodies or other serum proteins that bind to a px’s erythrocytes.

Labeled Immunoassay

A more specific and more sensitive compared to agglutination and precipitation reaction.

Referred to as receptor-ligand assays.

Fluorescent Antibody Test

A test that uses fluorescently labeled antibodies to detect specific antigens or antibodies.

Fluorescent isothiocyanate

Green fluorescence dye commonly used label in Fluorescent Antibody Test.

Tetramethyl Rhodamine

Red-orange fluorescence dye used for labeling.

phycocyanin

A red fluorescence dye used for labelling.

Fluorescence in situ Hybridization (FISH)

Test used to detecting and locating a specific DNA sequence on a metaphase chromosome and interphase of nucleus.

Competitive RIA

One of the most sensitive techniques for measuring hormones, drugs, and vitamins at concentration of <0.001.

Principle:

binding of radiolabeled Ag and unlabeled Ag to the limited supply of high affinity Ab.

Non-competitive RIA

Aka Sandwich Assay or IRMA

Bound radiolabeled Ab is directly proportional to the px’s Ag present in supernatant fluid.

Enzyme Immunoassay (EIA)

A technique that uses enzyme-labeled antibodies for the quantitative or qualitative measurement of antigens.

Western Blot

An analytical technique used to detect specific proteins in a sample, used as a confirmatory test for HIV.

PCR (Polymerase Chain Reaction)

A widely used method for amplifying specific DNA sequences.

Flow Cytometry

A technique for analyzing the physical and chemical characteristics of cells or particles suspended in a fluid.

Immunochromatography

A rapid test that employs antigen-antibody reactions, often used in point-of-care testing.