Evaluation of a modified FTA-ABS test multispot FTA-ABS

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Autoantibodies and the hepatitis-associated antigen in acute infective hepatitis

In 39 unselected patients with acute infective hepatitis diagnosed on clinical, epidemiological, and pathological findings, smooth muscle (S.M.) antibody was found in 87% and hepatitis-associated antigen in 33%. The incidence of S.M. antibody was highest during the first month after the onset of symptoms, and the antibody was preponderantly IgM at this stage.S.M. antibody and hepatitis-associated antigen occurred independently, and unlike hepatitis-associated antigen, which was strongly associated with possible parenteral exposure to infection, the incidence of S.M. antibody was not related to the presumed mode of exposure. It is concluded that production of S.M. antibody is more directly related to liver cell damage than to the presence of hepatitis-associated antigen in the serum.

Multispot immunofluorescence: a simple semi-automatic method of processing large numbers of tests

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Developments in immunofluorescence: the need for standardization

DIFFICULTIES EXPERIENCED BY THE NEWCOMER TO THE FLUORESCENT ANTIBODY STAINING METHOD LARGELY ARISE FROM TWO CAUSES: (1) the many modifications in the procedure which have been suggested over the last decade; (2) the variability of the basic reagent, fluorescent conjugate, in terms of potency and specificity. The ensuing problem of non-reproducibility is clearly an important factor for clinical laboratories now faced with increasing demands for routine tests involving immunofluorescence. In this paper a simple approach to standardization is described which, if adopted, would lead to a more efficient use of the method.

Quantitative studies of immunofluorescent staining. I. Analyses of mixed immunofluorescence

Mixed anti-globulin immunofluorescence (or mixed IF) was analysed 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: (1) the immunoelectrophoretic demonstration of antibodies to human IgG in anti-globulins; (2) titration of the antiglobulins and labelled globulins; and (3) determination of molar fluorescein to protein (F:P) ratios. Titration of anti-globulins (rabbit anti-human IgG) by gel precipitation afforded an assay of `units' of antibody activity. Similarly, `units' of labelled globulin antigen were determined by a 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 immunoglobulin if the latter has an 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.

The Influence of the A-Like Substance of Rabbits on Their Immune Response to Human Blood-Group A-Substance

Purified human blood group A substance from ovarian cysts may be rendered fully antigenic in rabbits by immunising with a streptococcal vaccine in which the organisms are “coated” with the substance. Specific precipitating antibody is obtained both in rabbits whose tissues contain A-like substance, and in rabbits which lack this substance. Evidence is presented that the antibodies produced by the two types of rabbit differ sharply in both specificity and serologic characteristics. Antibody obtained by this method in rabbits whose tissues contain A-like substance cannot be obtained by immunizing with human group-A red cells. The relationship of these findings to the problem of auto-antibody production is discussed.