DTH and antibody responses to Ph. sergenti salivary proteins.

BALB/c mice (six mice per group) were immunized in the right ear three times at two week intervals with plasmids encoding for fourteen Ph. sergenti salivary proteins (10μg), Ph. sergenti salivary gland homogenate (SGH, 0.5 pair), empty plasmid (VR1020, 10μg) or PBS (control) in total volume of 10 μl with PBS. Two weeks after the last immunization, the contralateral ear was intradermal challenged with 0.5 pairs of Ph. sergenti SGH. Data shown are from one representative of two independent experiments. (A) Delayed-type hypersensitivity response (DTH) generated at 48 h after Ph. sergenti SGH inoculation was determined. (B) Total IgG antibody response to Ph. sergenti SGH was determined by ELISA in immunized BALB/c. Statistical significance of the difference compared to the control empty-plasmid group (VR1020) is shown for each of the immunized groups. Dashed line, the cut off value determined as the mean + 3 SD of the response of the empty-plasmid control group.