The efficiency of using ELISpot on enriched IgA
B-cell fractions to enumerate F4-specific IgA
antibody secreting cells (ASCs).
A In one well, only one F4-specific IgA+ ASC was detected from 5 × 105 peripheral blood monomorphonuclear cells (PBMCs) (left) while 18 F4-specific spots were detected from 5 × 105 enriched IgA+ B-cells (right) at 21 days post primary immunization (dppi) of an oral immunized pig having maternal antibodies; each blue spot is counted as one F4-specific IgA+ ASC. B From eight wells, less than seven F4-specific IgA+ ASCs were detected from 4.0 × 106 PBMCs whereas more than 28 F4-specific IgA+ ASCs were detected from 4.0 × 106 enriched IgA+ B-cells at 21 dppi of the three immunized groups. The asterisk indicates a statistical significant difference (p < 0.05) between groups in comparison to the maternal-PBS group.