Murine memory B cells are multi-isotype expressors.
Flow cytometric analyses of the surface immunoglobulins of murine memory B cells revealed the existence of populations expressing multiple isotypes, including an IgM+/IgG+ population that could be stimulated in vitro with antigen to secrete both IgM and IgG. Female BALB/c mice were immunized with R-phycoerythrin (RPE), a fluorescent photosynthetic accessory protein from red algae. Pooled splenocytes from these mice at different stages of immunization were stained with RPE as well as with allophycocyanin- and fluorescein-conjugated anti-isotype antibodies and analysed on a two-laser FACS. RPE-binding cell sub-populations were defined and selectively sorted to verify their phenotype and to demonstrate that the various subpopulations (IgM+/IgG+, IgM+/IgG-, IgM-/IgG+) had different isotype-secretion patterns when challenged with RPE in vitro. These results re-affirm the notion that a transcriptional processing mechanism may be responsible for the simultaneous expression of multiple isotypes in memory cells.
Wu
C J
CJ
Department of Cellular and Development Biology, Harvard University, Cambridge, Massachusetts 02138.
Karttunen
J T
JT
Chin
D H
DH
Sen
D
D
Gilbert
W
W
D000818:Animals; D016175:B-Lymphocyte Subsets / Q000276:immunology*; D005260:Female; D007072:Immunoglobulin D / Q000032:analysis; D007074:Immunoglobulin G / Q000032:analysis; D007132:Immunoglobulin Isotypes / Q000032:analysis*; D007075:Immunoglobulin M / Q000032:analysis; D007156:Immunologic Memory; D051379:Mice; D008807:Mice, Inbred BALB C; D010799:Phycoerythrin / Q000276:immunology
D007072:Immunoglobulin D; D007074:Immunoglobulin G; D007132:Immunoglobulin Isotypes; D007075:Immunoglobulin M; D010799:Phycoerythrin