RT Journal Article SR Electronic T1 The Development of Optimally Responsive Plasmodium-specific CD73+CD80+ IgM+ Memory B cells Requires Intrinsic BCL6 expression but not CD4+ Tfh cells JF bioRxiv FD Cold Spring Harbor Laboratory SP 564351 DO 10.1101/564351 A1 Gretchen Harms Pritchard A1 Akshay T. Krishnamurty A1 Jason Netland A1 E. Nicole Arroyo A1 Kennidy K. Takehara A1 Marion Pepper YR 2019 UL http://biorxiv.org/content/early/2019/03/01/564351.1.abstract AB Humoral immunity depends upon the development of long-lived, antibody-secreting plasma cells and rapidly responsive memory B cells (MBCs). The differentiation of high affinity, class-switched MBCs after immunization is critically dependent upon BCL6 expression in germinal center (GC) B cells and CD4+ T follicular helper (Tfh) cells. It is less well understood how more recently described MBC subsets are generated, including the CD73+CD80+ IgM+ MBCs that initially form antibody-secreting effector cells in response to a secondary Plasmodium infection. Herein, we interrogated how BCL6 expression in both B and CD4+ T cells influenced the formation of heterogeneous Plasmodium-specific MBC populations. All Plasmodium-specific CD73+CD80+ MBCs required BCL6 expression for their formation, suggesting germinal center dependence. Further dissection of the CD4+ T and B cell interactions however revealed that somatically hypermutated CD73+CD80+ IgM+ MBCs can form not only in the absence of germinal centers, but also in the absence of CXCR5+ CD4+ Tfh cells.