Natural antibodies recognize these clusters on senescent erythrocytes. This secretory molecule production leads to the onset of a comprehensive senescent cell fate. SASP factors stimulate the immune system to eliminate senescent cells. Surfactant enhances the removal of inhaled particles and senescent cells away from the alveolar structure. Eliminating the senescent cells in mice prevented the side effects. Inflammation and damage to tissue are the underlying problems due to increased senescent cells. A confounding aspect of biological aging is the nature and role of senescent cells. At the limit the cells become senescent and cell division stops. The word "post-mitotic" is sometimes used to refer to both quiescent and senescent cells. The protein has multiple functions even presenting in senescent enrythrocyte antigens. For example, Rb was detected on the cyclin A and PCNA promoters in senescent cells. Unity Biotechnology is a startup biotechnology company that develops drugs which target senescent cells. Doxorubicin works by putting rampant cancer cells into a senescent state. The secretome of senescent cells is very complex. Protein turnover is believed to decrease with age in all senescent organisms including humans.