Figure 3. Prolactin increases the number of B cells co-expressing κ and λ light chains.

Flow-cytometric analysis showed that prolactin-treated mice (n=5) have a higher number of κ and λ dual-expressing T1 (A) and T2 B cells (B) than placebo-treated mice (n=5) (p=0.003 and p=0.004, respectively). C) Detection of κ⁺λ⁺ B cells by immunocytochemistry. The images a (phase-contrast), b (λ⁺ cells (green)), c (κ⁺ cells (red)) and d (the merged images) are from mice treated with placebo, and e, f, g and h show the phase-contrast, λ⁺ cells (green), κ⁺ cells (red) and merged images, respectively, from prolactin-treated mice. The arrows point out κ⁺λ⁺ cells. i) Confocal microscopy demonstrates that κ (iii) and λ (ii) light chains are co-expressed on the surface of the same B cell of a prolactin-treated mouse (iv). D). Effect of prolactin on λ⁺ B cells in the splenic B cell subsets. Placebo-treated mice showed a significant drop in the percentage of λ⁺ B cells during their maturation from T1 (5.9±0.63) to follicular (FO) (2.37± 0.58) B cells (p=0.0001). In prolactin-treated mice, the drop in the percentage of λ⁺ B cells from T1 to FO B cells was not statistically significant..