IDEHU   05542
INSTITUTO DE ESTUDIOS DE LA INMUNIDAD HUMORAL PROF. RICARDO A. MARGNI
Unidad Ejecutora - UE
artículos
Título:
Partial protection against Brucella infection in mice by immunization with nonpathogenic alpha proteobacteria
Autor/es:
DELPINO, MARIA VICTORIA; ESTEIN SILVIA,; ALBERTO FOSSATI, CARLOS; PABLO CESAR BALDI
Revista:
CLINICAL AND DIAGNOSTIC LABORATORY IMMUNOLOGY.
Editorial:
American Society for Microbiology
Referencias:
Lugar: Washington, DC; Año: 2007 vol. 14 p. 1296 - 1301
ISSN:
1071-412X
Resumen:
Previous findings indicate that Brucella antigens and those from nonpathogenic alpha-proteobacteria (NPAP) are cross-recognized by the immune system. We hypothesized that immunization with NPAP would protect mice from Brucella infection. Mice were immunized subcutaneously with heat-killed Ochrobactrum anthropi, Sinorhizobium meliloti, Mesorhizobium loti, Agrobacterium tumefaciens or B. melitensis H38 (standard positive control) before intravenous challenge with Brucella abortus 2308. Cross-reacting serum antibodies against Brucella antigens were detected at the moment of challenge in all NPAP-immunized mice. Thirty days after B. abortus challenge, splenic CFU counts were significantly lower in mice immunized with O. anthropi, M. loti and B. melitensis H38 than in the PBS controls [protection levels (log) 0.80, 0.66 and 1.99, respectively]. In mice immunized intraperitoneally with cytosoluble extracts from NPAP or Brucella abortus, protection levels were 1.58 for the latter, 0.63 for O. anthropi, and 0.40 for M. loti. To test whether the use of live NPAP would increase protection further, mice were both immunized and challenged through the oral route. Immunization with NPAP induced a significant increase of serum IgG, but not serum or fecal IgA, against Brucella antigens. After challenge anti-Brucella IgA increased significantly in serum and feces in mice orally immunized with O. anthropi. For all NPAP, protection levels were higher than those obtained with systemic immunizations, but were lower than those obtained by oral immunization with heat-killed B. abortus. These results show that immunization with NPAP, especially O. anthropi, confers partial protection against Brucella challenge. However, such protection is lower than that conferred by immunization with whole Brucella or its cytosoluble fraction.