FIG. 5.

Antitoxin antibody responses and toxin-neutralizing activity in prechallenge samples from vaccinated hamsters. Hamsters were immunized with partially purified C. difficile toxoid by sequential i.m. and r. regimens or i.m. regimens with or without adjuvant. (a) Antitoxin A (solid bars) or B (hatched bars) levels in serum were assessed at 1:50,000 dilution by ELISA. (b) Toxin-neutralizing activity against toxin A (solid bars) or B (hatched bars). (c and d) Toxin A-specific (solid bars) or B-specific (hatched bars) IgA or IgG levels in fecal extracts were analyzed at a 1:10 dilution. See Table 2 for a description of the immunization regimens used.