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Group A Streptococcus evades lysosomal degradation in macrophages (836.3)
Author(s) -
No Hyewon,
Snipper Joshua,
Till Andreas,
Okumura Cheryl
Publication year - 2014
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.28.1_supplement.836.3
Subject(s) - lysosome , green fluorescent protein , colocalization , microbiology and biotechnology , bacteria , immune system , biology , protein degradation , chemistry , enzyme , biochemistry , immunology , gene , genetics
Group A Streptococcus (GAS) has evolved multiple immune evasion strategies in order to successfully establish infections in otherwise healthy individuals. In this study, we sought to create a molecular tool to study intracellular trafficking and degradation of GAS by host phagocytic cells. We created a construct using a tandem red fluorescent protein linked to a pH‐sensitive green fluorescent protein (mWASABI), which degrades upon contact with the low pH environment of the lysosome. We confirmed successful cloning and expression of the construct into GAS and degradation of the green fluorescent protein under low pH conditions. However, to our surprise, infection of THP‐1 macrophage cells with the RFP‐mWASABI expressing bacteria in combination with immunofluorescent assays indicates the failure of the GFP to degrade in host cells despite bacterial colocalization with lysosomes. Our data suggests GAS either disables lysosomal acidification, thus preventing the activation of lysosomal degradative enzymes, or withstands the low pH environment and proteolytic enzymes present in the lysosomes. Current work focuses on elucidating specific bacterial factors involved in lysosomal resistance mechanisms. These studies contribute to our understanding of how GAS has evolved to circumvent cellular defense mechanisms and will aid in improving treatment options for GAS infections.