Germinal center B cells in Peyer's patches of aged mice exhibit a normal activation phenotype and highly mutated IgM genes

• Published in: Mechanisms of ageing and development Vol. 124; no. 2; pp. 155 - 165
• Main Authors: Rogerson, Brian J, Harris, David P, Swain, Susan L, Burgess, D.Ollie
• Format: Journal Article
• Language: English
• Published: Shannon Elsevier Ireland Ltd 01.02.2003; Elsevier Science
• Subjects: Aging; Aging - physiology; Analysis of the immune response. Humoral and cellular immunity; Animals; B-cells; B-Lymphocytes - cytology; B-Lymphocytes - physiology; Base Sequence; Biological and medical sciences; Fundamental and applied biological sciences. Psychology; Fundamental immunology; Germinal Center - cytology; Germinal centers; IgM; Immunobiology; Immunoglobulin M - genetics; Immunoglobulin Variable Region - genetics; Immunologic Memory - genetics; Mice; Mice, Inbred Strains; Molecular Sequence Data; Organs and cells involved in the immune response; Peyer's patches; Peyer's Patches - cytology; Phenotype; Somatic hypermutation; Somatic Hypermutation, Immunoglobulin - physiology; B-cells; Peyer's patches; Somatic hypermutation; Germinal centers; Aging; Mice; IgM; Senescence; Peyer patch; Immune response; Germinative center; Rodentia; Activation; B-Lymphocyte; Lymphoid tissue; Vertebrata; Phenotype; Mammalia; Mouse; Aged animal; Mutation; Humoral immunity; Immune system
• ISSN: 0047-6374; 1872-6216
• DOI: 10.1016/S0047-6374(02)00115-X

Systemic and mucosal humoral immune responses have been reported to exhibit an age related decline. However, differences in primary and memory responses at mucosal sites in aged mice have been noted. In an effort to begin characterizing deficiencies in the mucosal system of aged mice, we examined the B cell compartment of gut associated Peyer's patch lymphoid tissue. To our surprise, we found that germinal center (GC) B cells from aged B6D2F1 mice (24–26 months) were present at similar frequencies and exhibited a normal activation phenotype such as upregulation of B7.1, B7.2 and CD44, and downregulation of CD23, CD62L and CD38 as that observed in younger mice (2.5–4 months). As expected, Peyer's patch GC B cells from aged mice expressing V HX24 genes displayed higher somatic mutation frequencies compared with younger mice. However, this was particularly striking in IgM sequences where high mutational loads suggested we were sampling memory cells. It is conceivable that B-cells expressing these genes reflect the presence of a mucosal memory compartment in aged mice that either retains flexibility in effector function or is committed to the secretion of IgM antibody.