Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.|Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.|Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.|Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.|Department of Microbiology, Immunology, & Molecular Genetics, University of California Los Angeles, Los Angeles, CA, USA.