Figure 2.

Effect of LF and RA on Ig germ-line transcript expression and activity of the GLα promoter. (a) Diagram of DNA recombination occurring while switching to IgA. (b) Normal splenic B cells were cultured with LPS (12.5 μg mL⁻¹), LF (60 μg mL⁻¹), and RA (25 nM). After 2 days of culture, total RNA was isolated and the GLT, PSTα, CTα, AID, and β-actin levels were measured by RT-PCR. (c) CH12F3-2A B lymphoma cells were transfected with the M-GLα-luc reporter (10 μg) prior to treatment with LF (60 μg mL⁻¹) and RA (10 μM) for 18 h. Promoter activity was determined by luciferase activity. The data represent the mean of triplicate samples ± SEM. GLTs, germ-line transcripts; LF, lactoferrin; RA, retinoic acid; LPS, lipopolysaccharide; PSTα, α post-switch transcript; RLA, relative luciferase activity. **P < 0.01.