The zymosan-induced arthritis model is characterized by the release of pro-inflammatory cytokines, such as tumor necrosis factor (TNF), interleukin-18 (IL-18), interleukin-1β (IL-1β), and interleukin-6 (IL-6); synovial joint hypertrophy; and leukocyte recruitment. The gene discussed is IL1B; the disease is Arthritis.