Figure 2.

Secretion of interferon-γ (IFN-γ) or interleukin-17A (IL-17A) by antigen-specific CD4⁺ T cells following in vitro recall stimulation with pooled peptide fractions or Porphyromonas gingivalis. CD4⁺ T cells were purified from mice inoculated with pooled peptide in conjunction with lipopolysaccharide and incomplete Freund's adjuvant. 5 × 10⁵ CD4⁺ T cells were co-cultured with 3 × 10⁵ irradiated naive splenocytes in the presence of an appropriate pooled peptide fraction or P. gingivalis as recall antigen. Black bars represent the number of CD4⁺ T cells expressing IFN-γ or IL-17A per well. The recall antigen used is indicated below each bar and the makeup of the pooled peptide used to inoculate each mouse is given to the right of each graph pair. Mice inoculated with lipopolysaccharide plus incomplete Freund's adjuvant were the source of CD4⁺ T cells used as negative controls (open bars). Data represent the means of duplicate wells. One-tailed Student's t-test was used to determine if recall sample means were significantly larger than the re-stimulation without antigen (negative control: No Ag). P values < 0.05 or < 0.01 are indicated by a single or double asterisk, respectively. Data for all three P. gingivalis strains were pooled for this analysis.