On the cover: Histology of an ankle joint obtained from a mouse treated with K/B×N serum, but administered daily doses of rapamycin. The sample is stained with Alcian blue to detect glycosaminoglycans. Mouse models of both Lyme-associated and K/B×N-associated arthritis were suppressed by rapamycin treatment, concurrent with reduced lysosomal exocytosis. Bramwell, K. K. C., K. Mock, Y. Ma, J. H. Weis, C. Teuscher, and J. Weis. 2015. β-glucuronidase, a regulator of Lyme arthritis severity, modulates lysosomal trafficking and matrix MMP-9 secretion in response to inflammatory stimuli. J. Immunol. 195: 1647–1656.