Figure 4. IL4Ra signaling restrains memory B cell development at the CD23⁺ LZ stage.

(A-I) Immunized Il4ra^+/+ and Il4ra^−/− mice were analyzed on day 13. (A, B) Representative FACS profiles (A) and frequencies of CXCR4^lo CD86^hi LZ cells (B) in GC B cells. (C, D) Representative FACS profiles (C) and frequencies of CD23⁺ cells (D) in LZ GC B cells. (E, F) Representative FACS profiles (E) and frequencies of CD31⁺ cells (F) in CD23⁺ LZ GC B cells. (G, H) Representative FACS profiles (G) and frequencies of CD31⁺ CCR6⁺ cells (H) in GC B cells. (I) Frequencies NP⁺ memory B cells in B220⁺ GL7⁻ non-GC B cells. Data are pooled from two experiments. (J) Immunized Il4ra^+/+ and Il4ra^−/− mice were treated with EdU on day 11 post immunization and were analyzed on day 14. Frequencies of NP⁺ EdU⁺ memory B cells in B220⁺ GL7⁻ non-GC B cells. Data are pooled from two experiments. (K-N) Immunized mice received IL4-αIL4 complex or saline on day 11, 12, 13 post immunization and were analyzed on day 14. (K, L) Frequencies of CD23⁺ cells in LZ GC B cells (K left), CD31⁺ cells in CD23⁺ LZ GC B cells (K right), and CD31⁺CCR6⁺ cells in GC B cells (L). (M, N) Frequencies of NP⁺ memory B cells (M) and IgG1⁺ CD73⁺ memory B cells (N) in CD19⁺ GL7⁻ non-GC B cells. Each symbol represents one mouse. (K-M) One of three experiments with similar result is shown. (N) Data are pooled from three experiments. See also Figure S3.