Recombinant Mouse CD96 Protein, CF

Mouse CD96, also known as Tactile (T cell‑activated increased late expression), is a 160 kDa type I transmembrane glycoprotein of the Ig superfamily that shows peak expression 6 ‑ 9 days after activation of T, NK, and a subpopulation of B cells (1, 2). CD96 is also frequently expressed on acute myeloid leukemia and myelodysplastic stem cells (3, 4). Low expression of adhesive human CD96 is a rare cause of C syndrome, a set of developmental anomalies in cranial bone (trigonocephaly), skin and viscera, demonstrating a role for CD96 in development of these tissues (2, 5). Mouse CD96 cDNA encodes 602 amino acids (aa) including a 21 aa signal peptide, a 515 aa extracellular domain (ECD) that contains two V‑type and one C‑type Ig‑like  domain, a 21 aa transmembrane sequence, and a 45 aa cytoplasmic domain (1). Within the ECD, mouse CD96 shares 55% and 79% aa sequence identity with human CD96v2 and rat CD96, respectively (6). The ECD is highly N- and O‑glycosylated (1). Humans, but not mice, express a splice variant with a 16 aa insert in the second V‑type domain called CD96v1 (2). In mice, a truncated, potentially secreted 437 aa isoform is reported (7). An 80 kDa soluble form is elevated in human serum during chronic hepatitis B (8). The most N‑terminal Ig‑like domain of human or mouse CD96 binds to CD155/PVR (poliovirus receptor), but CD96/CD155 interaction is species‑specific (2, 6, 9). Mouse CD96 also binds nectin-1 (6). On NK cells, co‑stimulatory CD96 and DNAM‑1 (CD226) are thought to have paired activity with inhibitory TIGIT, all of which bind CD155 and various nectins (10, 11). CD96 can promote NK cell adhesion to, and killing of target cells, including tumors that express CD155 (9, 10).