Kinetics of the germinal center response after immunization.

<p>Cells from popliteal draining lymph nodes harvested at various times after immunization with VEE/SIN-H, FI-MV, SRBCs (positive control) or PBS were analyzed for GC B cells by flow cytometry. Cells were stained with antibody to CD19 and PNA at day 7 (<b>A</b>) and periodically over an 80-day time course (<b>B</b>). All flow cytometry data points represent values from cells pooled from 2 mice.</p

Measles virus-specific antibody response to immunization.

<p>Sera collected from individual mice immunized with VEE/SIN-H or FI-MV were assessed for quantity and quality of MV-specific antibody. MV-specific total IgG (<b>A</b>), IgG1 (<b>B</b>) and IgG2a (<b>C</b>) were measured by EIA. Avidity of MV-specific antibody was evaluated by a modified EIA and data are presented as an avidity index (<b>D</b>). Fifty percent plaque reduction neutralization titers (PRNT) for the Chicago-1 strain of MV on Vero cells are expressed as geometric means (<b>E</b>). Data points represent the mean +/- S.D. of three individual mice. (* <i>P</i><0.05; Student's <i>t</i> test)</p

Hemagglutinin-specific antibody-secreting cell recall responses.

<p>Mice immunized with FI-MV, VEE/SIN-H or mock-immunized with PBS were given VEE/SIN-H at day 81 after primary immunization, bled at days 4 and 8 post-secondary immunization and sacrificed at day 12. EIAs were performed to measure serum antibody with reactivity against MVL (* <i>P</i><0.05; Student's <i>t</i> test) (<b>A</b>) and H (<b>B</b>) induced in the recall response up to 12 days after administering VEE/SIN-H. ASCs in the draining LNs were assayed for total IgG and MV-specific antibody secretion by ELISpot (<b>C, D</b>) 12 days after secondary immunization. Serum antibody data points represent the mean +/− S.D. of 3 individual mice. IgG ELISpots were performed in triplicate (error bars represent S.D. of assay replicates) with cells pooled from 3 mice.</p

Measles virus-specific T cell responses after immunization.

<p>IFN-γ (<b>A</b>) and IL-4–secreting cells (<b>B</b>) from the dLN were measured at day 7 after immunization with VEE/SIN-H or FI-MV. Media-only stimulation represents <i>ex vivo</i> spontaneous secretion. This value has been subtracted from the MVL stimulation values. At days 7, 14 and 21 after immunization, cells from dLNs (<b>C, D</b>) and the spleen (<b>E, F</b>) were evaluated for IFNγ and IL-4 secretion after <i>ex vivo</i> stimulation with MVL antigen in ELISpot assays. Spot-forming cells are per 5×10⁵ total cells. Assays were performed in triplicate (error bars represent S.D. of assay replicates) with cells pooled from 3 mice.</p

Protein-specific antibody responses to vaccine antigens.

<p>Serum IgG specific for MV H (<b>A</b>), F (<b>B</b>) and N (<b>C</b>) proteins over a 125-day time course measured by EIA. H-specific ASCs from the bone marrow measured by ELISpot at day 125, represented as an index of total spot number multiplied by spot area (<b>D</b>). Serum antibody data points represent the mean +/− S.D. of 3 individual mice. IgG ELISpot data are generated from cells pooled from 3 mice.</p