Page 131 - LECTURE NOTES
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The indirect method can be constructed to react with human IgG or IgM
molecules use in antibody assays
o The major indicator systems include immunofluorescence assay (FA),
enzyme immunoassay (EIA), and radioimmunoassay (RIA)
Ex. The EIA procedure can be adapted to perform:
i. An enzyme linked immunosorbent assay (ELISA) where on
unlabelled antibody (the capture antibody) is bound to a solid
phase (e.g., a latex bead or the bottom of a micro titer plate well)
to “capture” the antigen and a second enzyme- labeled antibody
is added to detect the captured antigen
ii. Immunoperoxidase (IP) methods to demonstrate specific viral
antigen by light microscopy in tissues from biopsy or autopsy
specimens or cells form viral cell cultures.
Serologic Methods – detection of rising titers of antibody between acute &
convalescent stages of infection
Measurement of IgG antiviral antibodies is used to determine
immunity, while quantization of IgG or IgM antibodies can diagnose
current or recent infection. Generally IgM antibodies denote a new
or recent infection.
Classical techniques which measure only IgG or ‘total” antibodies
o Neutralization tests
o Complement fixation (CF)
o Hemaglutination inhibitation (HI)
Newer techniques, which are modified to detect either IgG or IgM are;
o Immunofluorescent Assay (FA)
o Enzyme linked immunosorbent assay (EIA)
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