l-Serine Auxotrophy Impairs Brucella Intracellular Replication
Brucella is a facultative intracellular pathogen able to invade and proliferate within a wide range of cell types. l-Serine biosynthesis is a major anabolic pathway in most organisms, but its contribution to Brucella persistence has not been characterized. In this issue, Révora et al. (e00840-19) show that disruption of the phosphorylated pathway for l-serine biosynthesis causes auxotrophy. The mutants can be internalized but are unable to proliferate intracellularly. Exogenous l-serine supplementation reverts auxotrophy and allows replication to resume. The results reveal a limited availability of l-serine within the host cell, highlighting the relevance of this biosynthetic pathway for Brucella pathogenesis.
Immunotherapy for the Management of Respiratory Fungal Infection
The immune response elicited by Pneumocystis drives Pneumocystis pneumonia (PcP)-associated respiratory dysfunction, and the inability of current treatment regimens to adequately control immunopathogenesis is likely responsible for many treatment failures. In this issue, Hoy et al. (e00640-19) demonstrate that combination therapy consisting of passive anti-Pneumocystis antibody and a clinically used immunomodulatory agent promotes rapid recovery from fulminant PcP. The efficacy of this treatment is likely mediated by several mechanisms, including opsonization of Pneumocystis, masking of immunopathogenic fungal antigens, and altering macrophage polarization and phagocytic function. These findings illustrate a potential role for passive antibody in the management of fungal infection.
- Copyright © 2020 American Society for Microbiology.
