QUANTITATIVE STUDIES OF IMMUNOFLUORESCENT STAINING .I. ANALYSES OF MIXED IMMUNOFLUORESCENCE

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  • 1 January 1967
    • journal article
    • research article
    • Vol. 12  (3) , 327-+
Abstract
Mixed anti-globulin immunofluorescence (or mixed IF) was analyzed using the following model system: calf thyroid sections, human anti-nuclear factor (ANF), rabbit antisera to human IgG and fluorescein-labelled human IgG. This system was characterized on the basis of: the immunoelectro-phoretic demonstration of antibodies to human IgG in anti-globulins; titration of the antiglobulins and labelled globulins; and determina-tion of molar fluorescein to protein (F: P) ratios. Titration of anti-globulins (rabbit anti-human IgG) bu gel precipitation afforded an assay of "units" of antibody activity. Similarly, "units" of labelled globulin antigen were determined by gel precipitation titration. Block titrations of these components of the indicator system against ANF serum yielded constant titres or "plateaux" of nuclear staining over a range of units of anti-globulin and of labelled immunoglobulin. Thus, the following predictions can be made. Optimal mixed IF staining may be attained with 4 units or more of an anti-globulin (anti-human IgG) and with 1 unit or more of a fluorescein-labelled human immunoglobu-lin if the latter has F: P ratio in the range of about 1:1 to 3:1. The titre of the ANF appears to be proportional to the F: P ratio over this range.