title: B cell memory in xid mice is long-lived despite reduced memory B cell frequency.
abstract: Brutons tyrosine kinase (Btk) deficient xid mice have a diminished primary T cell dependent immune response, resulting in a reduced memory B cell frequency. Boosting at 35 days post primary immunization, however, generates a normal secondary immune response, indicating a functional memory B cell compartment. The longevity of B cell memory appears to depend on both the presence of antigen and expression of cell survival genes such as bcl-2. Since there is a natural decay in the number of memory B cells over time and since xid B cells have been demonstrated to have reduced Bcl-2 levels, we aimed at determining whether B cell memory of xid mice would be long-lasting. This report demonstrates that memory B cell precursors are detectable in xid mice more than 100 days after primary immunization. Furthermore, a secondary immune response of normal magnitude and kinetics can be generated in xid mice at 150 days after primary immunization indicating that B cell memory is long-lived in xid mice. Thus, although survival of B cell memory is presumably dependent on immunoglobulin (Ig)-mediated interaction with antigen, this interaction does not depend solely on signalling through Btk.
authors.affiliation: Walter and Eliza Hall Institute of Medical Research, Royal Melbourne Hospital, Victoria, Australia.
authors.forename: A
authors.initials: A
authors.lastname: Ridderstad
authors.forename: D M
authors.initials: DM
authors.lastname: Tarlinton
mesh_terms: D000818:Animals; D001402:B-Lymphocytes / Q000166:cytology / Q000276:immunology*; D005260:Female; D007153:Immunologic Deficiency Syndromes / Q000235:genetics* / Q000276:immunology; D007156:Immunologic Memory / Q000235:genetics*; D018655:Lymphocyte Count; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008808:Mice, Inbred CBA; D008817:Mice, Mutant Strains; D014960:X Chromosome / Q000276:immunology*