OBJECTIVES/GOALS: Multiple sclerosis (MS) is a chronic inflammatory disease of the central nervous system. MS affects more than two million people worldwide, resulting in physical disability, cognitive impairment, and decreased quality of life. We are investigating the role of senescent cells, a hallmark of aging, in inflammation and disease progression in MS. METHODS/STUDY POPULATION: Female mice on a C57BL/6 background were subjected to the Hooke Laboratory EK-2110 experimental autoimmune encephalomyelitis protocol (EAE; n=10) to induce hind limb paralysis, and matching control mice received no injections (naīve; n=10). Immunofluorescent staining was used to visualize senescence cells and their localization in spinal cord tissue sections from naīve and EAE mice based on antibody detection of cell surface or intracellular proteins. Tissue sections from each group were analyzed in duplicates for each antibody (n=3-4/group). Flow cytometry was performed to immunophenotype the senescence cells using conjugated fluorescent antibodies to cell surface or intracellular proteins (n=5/group). RESULTS/ANTICIPATED RESULTS: Immunostaining demonstrated an increase in the cell senescence markers p16 (15-fold; unpaired t-test, p=0.01; n=3) and p21 (15-fold; unpaired t-test, p=0.003; n=3) in the spinal cord of EAE mice compared to naīve mice. Next, we showed that p16+ and p21+ cells increase with disease progression in the meninges adjacent to the ventral demyelinating lesions (one-way ANOVA, p=0.0009; n=3/group). We further found that 30±9.7% of M2 macrophages, a subset of myeloid cells, express p21 in the spinal cord of EAE mice by using flow cytometry analysis compared to only 5±1.6% in naīve mice (unpaired t-test, p=0.002; n=5/group). DISCUSSION/SIGNIFICANCE: Our findings demonstrate that senescent cells accumulate in the meningeal compartment following EAE induction, suggesting that decreasing senescent cell burden is a promising avenue in delaying disease progression and preventing neuroinflammation in MS.