• Vaccine Name: live attenuated Brucella abortus INTA2 vaccine
• Target Pathogen: Brucella spp.
• Target Disease: Brucellosis
• Vaccine Ontology ID: VO_0009144
• Type: Live attenuated vaccine
• Status: Research
• Host Species for Licensed Use: Cattle
• Host Species as Laboratory Animal Model: Mus musculus (BALB/c mice); BALB/c mice; Bos taurus (heifers)
• Antigen: bp26; bmp18; luc (marker gene) | bp26 gene replaced by luciferase coding gene
• Preparation: Live attenuated double mutant strain with bp26 replaced by luciferase gene and partial deletion of bmp18, lacking drug resistance markers. (Campos et al, 2002)
  Live attenuated mutant strain with bp26 replaced by luciferase gene. (Fiorentino et al, 2008)
• Description: Brucella abortus INTA2 is a novel mutant strain constructed by inactivation of two B. abortus strain 19 genes, bp26 and bmp18, replacing bp26 with the luciferase gene as a marker, aiming to reduce residual virulence and allow differentiation from field strains. Efficacy: INTA2 showed significantly reduced bacterial load in spleens during early infection and no splenomegaly, indicating reduced residual virulence; provided similar protection levels against virulent challenge as strain 19. Immune response: INTA2 induced O-side antibodies but did not express BP26, enabling differentiation of vaccinated animals from those infected with field strains by measuring anti-BP26 antibodies via agglutination test or ELISA. (Campos et al, 2002)
  Brucella abortus M1-luc is a mutant strain derived from strain 19 vaccine in which most of bp26 sequence has been replaced by the luciferase coding gene. Efficacy: Protection against abortion was 81.8% in heifers vaccinated with M1-luc, comparable to 78.6% protection with S19 vaccine. (Fiorentino et al, 2008)

Mouse Response

• Host Strain: BALB/c
• Immune Response: INTA2 induced O-side antibodies but did not express BP26, enabling differentiation of vaccinated animals from those infected with field strains by measuring anti-BP26 antibodies via agglutination test or ELISA. (Campos et al, 2002)
• Challenge Protocol: Inoculation of BALB/c mice with strain INTA2; evaluation of bacterial colonization in spleens, splenomegaly, and protection against virulent challenge compared to strain 19. (Campos et al, 2002)
• Efficacy: INTA2 showed significantly reduced bacterial load in spleens during early infection and no splenomegaly, indicating reduced residual virulence; provided similar protection levels against virulent challenge as strain 19. (Campos et al, 2002)
• Description: Inoculation of BALB/c mice with strain INTA2; evaluation of bacterial colonization in spleens, splenomegaly, and protection against virulent challenge compared to strain 19. (Campos et al, 2002)