FIG. 1.
Frequency of spontaneously secreting IgG AFCs (a to e) and memory B-cell-derived IgG AFCs (f to j) isolated from the peripheral blood of 12-month-old toddlers prior to and 1 week following a primary and secondary dose of Pnc7, as determined by ELISPOT assay. Immunizations were given on day 0 (d0) and day 56 (black arrows), with blood draws performed on days 0, 6 or 7, 56, and 62 or 63. IgG AFCs specific for the control antigen (tetanus toxoid) and the vaccine antigens (diphtheria toxoid and polysaccharide serotypes 4, 14, and 23F) were enumerated. The data represent the numbers of IgG AFCs/106 cultured PBMCs, and the bars represent the medians.