IMMUNOLOGICAL TESTS

SEROLOGICAL TESTSDiagnostic Immunological tests: Direct tests detect antigens (from patient

sample) Indirect tests detect antibodies (in patient's

serum)

DIAGNOSTIC IMMUNOLOGY: PRECIPITATION REACTIONS

Precipitation Reactions:

Involve soluble antigens with antibodies

Precipitin Ring test

Figure 18.3

PRECIPITATION TESTSExamples

Immunodiffusion: antibody and antigen react in agar to make ppt band or ring.

Immunoelectrophoresis: complex mixture of antigens separated, then reacted with antibody.

IMMUNOLOGIC TESTS:

Immunoelectrophoresis:

AGGLUTINATION REACTIONS Inexpensive, Simple,

Sensitive Involve particulate

antigens and antibodies

Antigens may be: On a cell (direct

agglutination) Attached to latex

spheres (indirect or passive agglutination)

Figure 18.4

HEMAGGLUTINATION Hemagglutination involves agglutination of RBCs.

Figure 18.7

PROZONE EFFECT

The lack of agglutination at high concentrations of antibodies is called the prozone effect.

Lack of agglutination in the prozone is due to antibody excess resulting in very small complexes that do not clump to form visible agglutination.

NEUTRALIZATION REACTIONS Antibodies help eliminate the harmful effect of a

virus or exotoxin Viral hemagglutination inhibition tests for the

presence of antibodies in a patients serum by the antibodies' ability to prevent viruses from agglutinating RBCs.

Figure 18.8b

ANTIBODY TITER

Is the concentration of antibodies against a particular antigen

Figure 18.5

COMPLEMENT FIXATION

Figure 18.9.1

COMPLEMENT FIXATION

Figure 18.9.2

FLUORESCENT ANTIBODY TECHNIQUES (DIRECT)

Figure 18.10a

FLUORESCENT ANTIBODY TECHNIQUES (INDIRECT)

Figure 18.10b

ENZYME-LINKED IMMUNOSORBENT ASSAY(DIRECT ELISA)

Figure 18.12a

ENZYME-LINKED IMMUNOSORBENT ASSAY (INDIRECT ELISA)

Figure 18.12b

IMMUNOLOGIC TESTS: 6) WESTERN

BLOT Used to id specific

proteins in mixtures Proteins are separated

on SDS-PAGE Proteins then

transferred to membrane

Membrane flooded w/ radio-labelled or enz-linked poly/monoclonal Ab’s specific for protein

SEROLOGICAL TESTS

Figure 18.13

SEROLOGICAL TESTS: SUMMARY

Precipitation: Soluble antigens Agglutination: Particulate antigens Hemagglutination: Agglutination of RBCs Neutralization (inhibition): Inactivates toxin or virus Fluorescent-antibody technique: Antibodies linked to

fluorescent dye Complement fixation: RBCs are indicator ELISA: Enzyme linked to antibody amplifies results for

easier visibility and more sensitivity.

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