Senescent BALB/c mice (2 years old) exhibit decreased numbers of both large and small CD43- CD25+ B220+ pre-B cells within the bone marrow when compared with 3-4 month old mice. Little alteration in the numbers of pro-B cells (CD43+ CD25- B220+) and early pre-B cells (CD43+ CD25+ B220+) are seen in BALB/c mice with age. The remaining large CD25+ B220+ pre-B cells in senescent BALB/c mice display extensive mitotic activity, with >60% of these pre-B cells in S + G2/M. Therefore, senescent BALB/c mice have altered recruitment of nascent CD43+ pre-B cells into the CD43- pre-B cell compartment. Since this recruitment is dependent upon the expression of surrogate light chains (λ5, VpreB) and their association with μ heavy chains to form the pre-B cell receptor, λ5 surrogate light chain protein was measured in ex vivo CD43+ B220+ pro-B/early pre-B cells as well as from IL-7 stimulated pro-B/pre-B cells derived in vitro. Reduction in both cytoplasmic and surface λ5 surrogate light chain expression was seen among pro-B/early pre-B cells from senescent BALB/c mice. Initial experiments using semi-quantitative RT-PCR indicate that decreased λ5 mRNA is seen in senescent BALB/c mice. Reduced surrogate light chain expression may result in altered pre-B cell receptor expression in senescent BALB/c mice and a decline in pre-B cell formation and expansion.
|Original language||English (US)|
|State||Published - Mar 20 1998|
ASJC Scopus subject areas
- Molecular Biology