Serology Day 2 - Serological techniques, TORCH, syphilis Flashcards
Immunofixation Electrophoresis
Serum run on different rows of gel, anti-antibodies used to see each type of immunoglobulins in each row
Titer results
Dilution factor of last dilution that shows positive result
Pre-zone
More antibodies than antigen
Post-zone
More antigen than antibody
Zone of equivalence
Antigen and antibody concentrations close enough to form immune complexes
Precipitation assays
soluble antigen reacts with soluble antibody (turbidity/nephelometry)
Ouchterlony formation patterns
Identity: solid bent line between antibody, unkown antigen, and standard antigen
Non-identity: crossed lines, little similarity between standard and unkown antigen
Partial identity: lines close but obviously distinct, standard and unknown antigen have similar epitopes
Radial immunodiffusion
Agar has antibody in it, patient sample added to well, allowed to difuse
Ring is formed, diameter of ring is proportional to concentration
Immunoelectrophoresis
Antigens run on gel first, trough cut and antibody added which diffuses
Hypogammaglobulinemia
Low amounts of Ig’s
A-gammaglobulinemia
Absence of Ig’s
Hypergammopathy
Too many Ig’s
Direct agglutination
Antigen directly combines with antibody
Indirect agglutination
Carrier molecule coated with antigen, reacts with antibody in more visible way
Hemmaglutination
ABO blood group assay
Flocculation test
Precipitate of fine particles, use indirect method
Complement fixation test
No hemolysis = complement reacted with Ag/Ab complex (Ab is present in patient)
Hemolysis = complement not fixed onto Ag/Ab complex, no Ab in patient
Western Blot
Proteins, using electrophoresis the use anti-protein antibody
Southern Blot
DNA, using electrophoresis and radioisotopes
Heterophile antibodies
IgM’s produced in infection that are capable of binding to unrelated antigens from other species
Forssman antibody
Antibody developed during mono infection also reacts against guinea pig kidney and sheep RBC
Heterophile antibody tests
Paul Bunnell, Dadisohn Differential
TORCH
Toxoplasmosis Other Rubella Cytomegalovirus Herpes
Toxoplasma gondii
Asymptomatic to mono-like symptoms (birth defects cause hydrocephalus)
Domestic cat is host, difficult to culture, use EIA to test
Cytomegalovirus
Part of herpes family (stays latent mostly, mild mono-like symptoms when reactivates), almost everyone has it (passed by fluids)
Rubella
“3 day measles”, serious birth defects like CHF, considered immune at 1:8 titer, 4 fold increase shows recent infection
Herpes
Genital virus, can pass to baby during birth if mom is active, can kill infant
Syphilis bacterium
Treponema pallidum (a spirochete)
Syphillis (background info)
Can be destroyed by heat, cold, and drying
Need direct contact with open lesion to pass on, can pass to infants during birth
Treat with penicillin
Syphillis clinical presentation
Primary: chancre (gential lesion)
Secondary: malaise, asymptomatic
Tertiary: inflammation, neurosyphillis
Syphillis screening
Start with non-treponemal antibodies (reagin), then look for treponemal antibodies
Nontreponemal tests
Venereal Disease Research Laboratory (VDRL) and Rapid plasma reagin (RPR)
VDRL test
Looking for flocculation on slide, can do quantitative to monitor treatment, CSF can only be tested via VDRL
RPR test
Looking for flocculation, sensitive, faster than VDRL
Treponemal tests
Fluorescent treponemal absorption (FTA-ABS) and T pallidum particle agglutination (TP-PA)
FTA-ABS test
Incubate with sorbent (remove cross-reacting antibodies), incubated on slide with killed T pallidum, use fluorescent anti-human Ig antibody to view
TP-PA test
Patient serum incubated wit gel particled covered in T pallidum antigen, smooth mat on surface of well is positive rxn, button is negative rxn
Typical antibody patterns in syphillis
Treponemal antibodies stay high throughout all stages, even after treatment
Nontreponemal antibodies decrease as disease become latent (treated drops lower than untreated)
