Morphology of CpG DNA₂₀₀₆–activated CD27⁺ and CD27⁻ B cells. Wright-Giemsa staining was used to demonstrate morphologic differences between the initial CD27⁺ and CD27⁻ peripheral blood B cells as well as differentiation changes following each phase of the culture system for both populations. By the end of phase III, CD27⁺ and CD27⁻ B cells had an identical plasmablast morphology. Results are representative of 4 independent experiments, each from a different blood donor. Images were photographed using a Nikon Labophot microscope (100×/1.17 numerical aperture oil objective) with a Nikon Coolpix digital camera using the manufacturer's software (Nikon, Melville, NY). JPEG images were viewed using Adobe Photoshop CS2 (Adobe Systems, San Jose, CA), and contrast adjustments were made.