Antibodies were raised in goat to human IgA. There is low background fluorescence in normal tissue in contrast to cases of autoimmune desease where IgA is depostited. No cross reactivity with albumine fractions of human serum. No cross reactivity with albumin fractions of animal species.
From the crude polyclonal the cross reactive antibodies were extracted by incubation with Sepharose-bound human IgM and IgG.
Specific antibodies were absorpted by incubation with Sepharose-bound human IgA.
Specific antibodies were eluted by acidic buffer at pH 2.5 followed by neutralisation and dialysis.
After repeated binding with immobilized human IgA a minimum of 65% protein bound.
The purified polyclonal was conjugated to fluorescein isothiocyanate isomer I followed by gel-filtration and ion-exchange chromatography to clear unbound conjugate.
F/P ratio is 4-6 mol Fluorescein per 1 mol of goat IgG.