E1A and E1B transcripts are differentially produced in B and T lymphocytes. (A) Tonsillar B-1a, B-1b, and B-2 cells were sorted based on their membrane expression of CD5 and CD45RA. The numbers of E1A- and E1B-containing transcripts were determined in these 3 subpopulations by quantitative PCR. (B) In situ hybridization analysis of cytospun tonsillar T and B cells (× 400) with sense and antisense probes for E1A (top) and E1B (bottom). The transcripts were revealed using digoxigenin-labeled probes. E1B transcript–containing cells are denoted by the arrows. (C) Localization of E1A and E1B transcript–containing cells (arrows) in tonsil sections (× 100). Germinal center (GC), follicular mantle (FM), and T-cell areas are indicated. Images were captured using a Zeiss Axioplan microscope (Zeiss, Oberkochen, Germany) using 40 ×/0.75 numeric aperture (NA) (B) and 10 ×/0.30 NA (C) objectives. Images were acquired with an Olympus Camedia C-4040 zoom digital camera and Camedia master 2.5 imaging solution, and were processed using Adobe Photoshop (Adobe Systems, San Jose, CA).