Recombinant Lactobacillus were treated with and without 250 kU/ml of Lyz in TGF buffer [100 mM Tris-HCl pH.8, 50 mM glucose, 1% FBS (v/v) (Hyclone, South Logan, UT)] for 30 min. Cells were washed and resuspended in TGF buffer with mAb LA2.2 (1:100) for 1 h at room temperature, washed three times with 500 ml TGF buffer and resuspended on 100 ml of the same buffer. Aliquots of 10 ml were placed on slides and air-dried at 37uC for 1 h. Slides were incubated with Alexa Fluor 488labeled goat anti-mouse IgG antibody (1:250) (Molecular Probes, Invitrogen, Carlsbad, CA) in 100 ml TGF buffer at 23uC for 1 h with intermittent gentle mixing. After incubation, slides were washed three times with TGF buffer and fixed with 4% PBSbuffered formaldehyde (methanol free; Ted Pella Inc., Redding, CA) for an additional 15 min at room temperature. Labeled cells were mounted in VectaShield medium containing 4,6-diamidino-2-phenylindole (DAPI; Vector Laboratories, Burlingame, CA) and visualized using a Zeiss inverted Axiovert 200 motorized microscope and analyzed using the Axiovision 4.3 software.