Clone REA692 recognizes the mouse T cell immunoglobulin mucin receptor 1 (TIM-1) antigen, a single-pass type I membrane protein, also known as hepatitis A virus cellular receptor 1 (HAVcr-1) or kidney injury molecule 1 (KIM-1). The TIM gene family is involved in a variety of immunity related processes including T cell proliferation and survival, tissue inflammation, and atopy. In mice, eight TIM genes encode the proteins TIM-1 to TIM-8, whereas only three TIM genes are found in humans encoding TIM-1, TIM-3, and TIM-4. Several lines of evidence suggest that TIM-1 regulates T cell activity

through responses mediated by Tʜ1, Tʜ2, Tʜ17, and regulatory T cells. TIM-1 is recruited to the T cell receptor signaling complex and has a costimulatory role. TIM-1 expression has been demonstrated in epithelial cells, especially those of kidney origin, and is greatly increased in both mouse and human kidneys after injury. While absent on naive CD4 T cells, TIM-1 expression increases following TCR stimulation to provide positive co-stimulatory signal in T cell proliferation and Tʜ1/Tʜ17 cytokine production. It is reported, that the interaction of TIM-1 with TIM-4 is involved in the regulation of T cell proliferation.