Protection of Mice against Brucellosis by Vaccination withBrucella melitensisWR201(16MΔpurEK)

Abstract

Human brucellosis can be acquired from infected animal tissues by ingestion, inhalation, or contamination of the conjunctiva or traumatized skin by infected animal products. A vaccine to protect humans from occupational exposure or from zoonotic infection in areas where the disease is endemic would reduce an important cause of morbidity worldwide. Vaccines currently used in animals are unsuitable for human use. We tested a live, attenuated, purine-auxotrophic mutant strain of Brucella melitensis, WR201, for its ability to elicit cellular and humoral immune responses and to protect mice against intranasal challenge with B. melitensis 16M. Mice inoculated intraperitoneally with WR201 made serum antibody to lipopolysaccharide and non-O-polysaccharide antigens. Splenocytes from immunized animals released interleukin-2 (IL-2), gamma interferon, and IL-10 when cultured with Brucella antigens. Immunization led to protection from disseminated infection but had only a slight effect on clearance of the challenge inoculum from the lungs. These studies suggest that WR201 should be further investigated as a vaccine to prevent human brucellosis.

Nasal vaccination stimulates CD8+ T cells for potent protection against mucosal Brucella melitensis challenge

“…Consequently, parenteral vaccination proved ineffective for brucellae clearance from the lungs. 37,38 Furthermore, the few studies that have tested mucosal routes of vaccination to protect against pulmonary disease were discouraging. One such study tested oral immunization with γ-irradiated Brucella neotomae, and found that bacterial colonization of spleen and lung tissues was reduced only by 15.8-fold.…”

CD8 Knockout Mice Are Protected from Challenge by Vaccination with WR201, a Live Attenuated Mutant ofBrucella melitensis

“…B. melitensis 16M and WR201 from our culture collection were prepared as described previously [ 12 ]. WR201 from stocks frozen in 50% glycerol was incubated overnight in Brucella broth in a shaker flask at 37°C.…”

“…CFU concentration was verified by serial dilution and plating on Brucella agar. Rough Brucella lysate (RFBL) and Brucella LPS were prepared as previously described [ 12 ].…”

“…Immunization with B. melitensis WR201, an attenuated purine auxotroph, protects mice against intranasal challenge with virulent B. melitensis 16M [ 12 ]. Protection is associated with production of anti-lipopolysaccharide (LPS) antibodies and production of IFN- γ by antigen-stimulated immune spleen cells.…”

Pathologic changes associated with brucellosis experimentally induced by aerosol exposure in rhesus macaques ( Macaca mulatta )

“…Data from other studies 5,6 have revealed that at least 2 vaccines that are candidates for use in humans are immunogenic and protective against respiratory challenge in mice. A number of studies [7][8][9][10][11] have indicated that nonhuman primates are susceptible to infection with virulent or attenuated strains of Brucella organisms administered by oral, SC, or respiratory routes.…”