Confocal microscopic examination of Leishmania major rosettes labeled with Poly α 2,8 N-acetyl neuraminic acid (PSA) and PSA containing de-N-acetyl neuraminic acid (NeuPSA). A, light micrograph with DAPI-fluorescent labeling overlay; B, anti-PSA mAb 2-1-B/DAPI labeling; C, anti-NeuPSA mAb SEAM 2/DAPI labeling; D, composite of mAb 2-1-B/mAb SEAM 2/DAPI labeling. Individual promastigote cells within the rosette expressing PSA, NeuPSA or both can be observed. Scale bars, 10 µm.