Detection of Semaphorin 7A in Human PBMCs by Flow Cytometry. Human peripheral blood mononuclear cells (PBMCs) treated with PHA were stained with Mouse Anti-Human Semaphorin 7A PE‑conjugated Monoclonal Antibody (Catalog # FAB20681P, filled histogram) or isotype control antibody (Catalog # IC0041P, open histogram). View our protocol for Staining Membrane-associated Proteins.
Preparation and Storage
The product is shipped with polar packs. Upon receipt, store it immediately at the temperature recommended below.
Stability & Storage
Protect from light. Do not freeze.
12 months from date of receipt, 2 to 8 °C as supplied.
Background: Semaphorin 7A
Semaphorin 7A (Sema7A, designated CD108, previously Sema K1 or Sema L), is an ~80 kDa membrane-anchored glycoprotein that is a member of the Semaphorin family of axon guidance molecules (1-4). On human erythrocytes, it is the John Milton Hagen (JMH) blood group antigen (4). Sema7A is the only known Class 7 or glycophosphatidylinositol (GPI)-linked semaphorin; its expression is concentrated in the brain, spleen and thymus (1-5). Human Sema7A cDNA encodes a 44 amino acid (aa) signal sequence, a 604 aa extracellular domain (ECD) including Sema and C2‑type Ig-like domains, and an 18 aa propeptide/GPI membrane anchor signal sequence. Mature human Sema7A shares 89%, 89%, 88%, 86% and 90% aa identity with mouse, rat, canine, bovine and equine Sema7A, respectively. The Sema7A sema domain contains an RGD integrin interaction motif (4). Although it binds plexin-C1 in vitro and may be coexpressed with it, many of its activities depend on interaction with beta 1 integrins such as alpha 1 beta 1 (6-10). Sema7A signaling through the two receptors may cause opposing effects (8). Sema7A is an immune semaphorin, with expression and activity on CD4+CD8+ thymocytes, activated T cells, macrophages and microglia (2, 9-12). T cell Sema7A interacts with monocytic cells, stimulating their chemotaxis, production of pro-inflammatory cytokines, and dendritic differentiation (5, 6). However, on the T cells themselves, Sema7A downregulates T cell Receptor (TCR) signaling by promoting TCR internalization, modulating T cell responses (9). In lung macrophages, Sema7A is induced by TGF-beta and participates in TGF-beta -induced lung fibrosis (12). Sema7A is also expressed on pre-osteoblasts and osteoclasts, where it promotes migration and fusion, respectively; on keratinocytes, where it promotes melanocyte spreading and dendricity; and on some neurons, for example, promoting axon outgrowth in the developing olfactory tract (8, 10, 13).
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