ANTAGONISM BETWEEN 2 IMMUNOGENS EXTRACTED FROM BRUCELLA (CELL-WALL PEPTIDOGLYCAN AND LIPOPOLYSACCHARIDE FRACTIONS) AND INACTIVITY OF THE BRUCELLIN ALLERGEN IN IMMUNIZATION OF THE MOUSE

  • 1 January 1980
    • journal article
    • research article
    • Vol. A131  (2) , 157-169
Abstract
Three fractions extracted from Brucella possessing immunogenic activity were tested either as unique antigens or in combinations using various dose levels. Immunity in the mouse was tested 1 mo. after vaccination by the i.p. administration of a virulent strain of B. abortus and the spleen count of Brucella 15 days after challenge. The brucellin protein fraction, the cutaneous hypersensitivity reagent, did not elicit an immune response in the mouse and did not interfere with immunization PG [peptidoglycan] (cell wall PG extracted with SDS [sodium dodecyl sulfate]) and LPS [lipopolysaccharide] fractions. The PG fractions, extracted either from B. abortus (PG-F8) or from B. melitensis (PG-F7), conferred good dose-dependent immunity used on their own. The LPS fraction (B. melitensis) on its own also conferred good immunity but the dose-response curve was less regular. Immunity induced by either fraction was not affected by the presence of an oil adjuvant. Various dose-ratio combinations of PG and LPS were studied with respect to their interactions in 3 successive factorial experiments. The interactions were consistently significant and largely negative. According to the dose of each fraction and the ratio, the immunity was either equivalent to that produced by the most active fraction in the combination (no additive effect) or less (antagonism). The antagonism between 2 vaccinal fractions extracted from the same bacteria pleads in favor of purified vaccines.