Adjuvant activities of COL to boost humoral and cellular immune responses. (A) BALB/c mice (n = 3 each) were left nonimmunized or immunized twice by subcutaneous injections of OVA (400 μg per animal) plus vehicle alone or COL (6 μg per animal). Serum samples collected 7 days after the second immunization were examined for OVA-specific immunoglobulins of the indicated isotypes (mean ± SD from 3 independent animals each). (B) The draining LN cells harvested from the same immunized mice were examined for proliferative responsiveness in the presence or absence of OVA (100 μg/mL) by 3H-thymidine uptake on day 4 (mean ± SD; n = 3 each). Statistically significant differences compared with the control panel immunized with OVA plus vehicle alone are indicated with asterisks (*P < .05, **P < .01).