J Res Notes | Volume 1, Issue 1 | Research Article | Open Access

Disruption of Brucella Suis InvA and InvB Encoding Putative Invasion Proteins Affects Growth in Culture, Uptake and Persistence in Macrophages, and Persistence in CD1 Mice

Aloka B Bandara^1*, Victor Dobrean², Nammalwar Sriranganathan², Gerhardt G Schurig² and Stephen M Boyle²

¹Department of Human Nutrition, Foods and Exercise, Virginia Polytechnic Institute and State University, USA
²Department of Biomedical Sciences and Pathobiology, Virginia Polytechnic Institute and State University, USA

^*Correspondance to: Aloka B Bandara 

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Abstract

An intracellular bacterial pathogen requires four steps for a successful infection: Adherence, Invasion, establishment, and dissemination within the host. Putative Invasion (Inv) proteins or nudix hydrolases are believed to contribute in these infection steps. The genome of Brucella suis strain 1330 carries (i) an InvA gene that is homologous to InvA or nudix hydrolases; and (ii) and an InvB gene that is homologous to InvB of other bacteria. We investigated the role of B. suis InvA and InvB on in vitro growth and multiplication in macrophages, and in vivo persistence in CD1 mice. The InvA and InvB genes of B. suis strain 1330 were disrupted by allelic exchange to construct isogenic InvA and InvB mutant strains, respectively. The wild-type InvA and InvB genes were introduced into the mutant strains to generate isogenic, complemented mutant strains. Compared to the wild type, both mutants grew slower in enriched broth or on agar medium. The mutant strains were less capable of InvAding and persisting in J774.1 macrophage cell line in vitro. The InvB mutant cleared from spleens of inoculated CD1 mice faster than the wild type or the InvA mutant. Mice inoculated with the attenuated InvB mutant expressed specific serum antibodies of immunoglobulin 2a isotype and exhibited substantial protection against challenge with virulent B. suis strain 1330. Disruption of B. suis InvA and InvB impaired the strains’ growth in culture, uptake into and survival in macrophage cell line, and persistence in mice. The InvB mutant strain induced immunity and protection in mice against B. suis challenge. The out-bred CD1 mouse model was useful in studying B. suis pathogenesis.

Keywords:

Brucella; Invasion protein; Nudix hydrolase; Persistence; Protection

Citation:

Bandara AB, Dobrean V, Sriranganathan N, Schurig GG, Boyle SM. Disruption of Brucella Suis InvA and InvB Encoding Putative InvAsion Proteins Affects Growth in Culture, Uptake and Persistence in Macrophages, and Persistence in CD1 Mice. J Res Notes. 2018;1(1):1004.