A second mutation has recently been identified in the previously described Brucella abortus htrA mutant PHE1. As a result of this finding, a new B. abortus htrA mutant, designated RWP11, was constructed to evaluate the biological function of the Brucella HtrA protease. RWP11 is more sensitive to oxidative killing in vitro and less resistant to killing by cultured murine neutrophils and macropha...

brucellosis, caused by brucella spp., is an important zoonotic disease that causes abortion and infertility in cattle and undulant fever in humans. various studies have examined cell-free native and recombinant proteins as candidate protective antigens in animal models. among brucella immunogenes, antigen based on ribosomal preparation has been widely investigated. in this study, the immunogeni...

Few data are available on the prevalence and relevance of chlamydiae in wild mammals, and even fewer studies have been conducted to determine the prevalence of Chlamydophila abortus in wildlife hosts, most probably due to the absence of suitable species-specific serological assays for testing sera from wild animals. In light of this, we have developed two in-house blocking-ELISA tests for detec...

In pregnant ruminants, Brucella abortus localizes and replicates within the rough endoplasmic reticulum of trophoblastic epithelial cells. In this study, Vero cells were exposed to B. abortus to investigate its internalization and intracellular growth in nonphagocytic cells. A new double-fluorescence staining procedure to discriminate between extracellular and intracellular bacteria was develop...

Brucella abortus strain RB51 is an attenuated rough mutant used as the live vaccine against bovine brucellosis in the United States and other countries. We previously reported the development of strain RB51 as a bacterial vaccine vector for inducing Th1-type immune responses against heterologous proteins. Because safety concerns may preclude the use of strain RB51-based recombinant live vaccine...

Brucella spp. are pathogenic bacteria that cause brucellosis, an animal disease which can also affect humans. Although understanding the pathogenesis is important for the health of animals and humans, little is known about virulence factors associated with it. In order for chronic disease to be established, Brucella spp. have developed the ability to survive inside phagocytes by evading cell de...

Cellular immune responses are a critical part of the host's defense against intracellular bacterial infections. Immunity to Brucella abortus crucially depends on antigen-specific T cell-mediated activation of macrophages, which are the major effectors of cell-mediated killing of this organism. T lymphocytes that proliferate in response to B. abortus were characterized for phenotype and cytokine...

Brucella abortus readily multiplies in professional or nonprofessional phagocytes in vitro and is highly virulent in mice. Isogenic mutants of B. abortus biovar 1 strain IVKB9007 lacking the ATP/GDP-binding protein motif A (P-loop) (named looP; designated here the IVKB9007 looP::Tn5 mutant) and the ATP-binding/permease protein (cydC; designated here the IVKB9007 cydC::Tn5 mutant) were identifie...

Brucella taxonomy is perpetually being reshuffled, at both the species and intraspecies levels. Biovar 7 of Brucella abortus was suspended from the Approved Lists of Bacterial Names Brucella classification in 1988, because of unpublished evidence that the reference strain 63/75 was a mixture of B. abortus biovars 3 and 5. To formally clarify the situation, all isolates previously identified as ...

Brucella abortus is a facultative intracellular bacterial pathogen that causes abortion in domestic animals and undulant fever in humans. Recent studies have revealed that Toll-like receptor (TLR)-initiated immune response to Brucella spp. depends on myeloid differentiation factor 88 (MyD88) signaling. Therefore, we decided to study the role of the interleukin-1 receptor-associated kinase 4 (IR...