A study was conducted to determine the effect of
monophosphoryl lipid A (MPL) and
trehalose dimycolate (TDM) as adjuvants on the protective responses in BALB/c mice vaccinated with Brucella abortus
salt-extractable
protein (BCSP) or
proteinase-K-treated B abortus
lipopolysaccharide (PKLPS). Mice were vaccinated with different doses of BCSP or PKLPS given alone or in combination with MPL or TDM. Mice were challenge-exposed 4 weeks later with virulent B abortus strain 2308. Two weeks after challenge exposure, the number of B abortus colony-forming units (CFU) per spleen, spleen weights, and spleen cell
interleukin 1 production were measured. Serum
IgG and
IgM concentrations specific for vaccinal immunogens were measured before and after challenge exposure with B abortus. Spleen weights and mean B abortus CFU per
vaccine group were significantly lower in BCSP- and PKLPS-vaccinated mice, compared with those of nonvaccinated control mice.
Monophosphoryl lipid A enhanced the suppression of splenic
infection when given with the BCSP
vaccine, but not when given with the PKLPS
vaccine.
Trehalose dimycolate had no effect on mean CFU when given with BCSP, but incorporation of TDM resulted in a significant increase in mean CFU when given with PKLPS. Spleen weights in BCSP- or PKLPS-vaccinated mice were not different when these
vaccines were combined with MPL or TDM. Because of the wide variation in the results, we could not conclude that vaccination with BCSP or PKLPS alone, or in combination with MPL altered spleen cell
interleukin-1 production in B abortus-infected mice.(ABSTRACT TRUNCATED AT 250 WORDS)