Biomarker for replicative senescence

1. A method comprising:

(a) contacting a population of chemically-fixed human cells comprising both proliferating and senescent cells with non-human antibodies that specifically bind human lamin B1 (anti-LB 1 antibodies) under conditions which result in formation of a complex between the anti-LB 1 antibodies and human lamin B1 present on cells within the population, wherein said anti-LB 1 antibodies bind to lamin B1, but not to Lamin B2 and Lamin A/C;

(b) binding fluorophore-tagged secondary antibodies to said anti-LB 1 antibodies; and

(c) detecting fluorescence from said fluorophore.