Any use of products other than the permitted use without the express written authorization of Becton, Dickinson and Company is strictly prohibited.
Apoptosis is a normal physiologic process that occurs during embryonic development as well as in maintenance of tissue homeostasis. The apoptotic program is characterized by certain morphologic features, including loss of plasma membrane asymmetry and attachment, condensation of the cytoplasm and nucleus, and internucleosomal cleavage of DNA. Loss of plasma membrane asymmetry is one of the earliest features. In apoptotic cells, the membrane phospholipid phosphatidylserine (PS) is translocated from the inner to the outer leaflet of the plasma membrane, thereby exposing PS to the external cellular environment. Annexin V is a 35-36 kDa Ca2+ dependent phospholipid-binding protein that has a high affinity for PS, and binds to cells with exposed PS. Annexin V may be conjugated to fluorochromes including BD Horizon™ BV421. This format retains its high affinity for PS and thus serves as a sensitive probe for flow cytometric analysis of cells that are undergoing apoptosis. Since externalization of PS occurs in the earlier stages of apoptosis, BV421 Annexin V staining can identify cells undergoing apoptosis at an earlier stage rather than assays based on nuclear changes such as DNA fragmentation.
BV421 Annexin V staining precedes the loss of membrane integrity which accompanies the latest stages of cell death resulting from either apoptotic or necrotic processes. Therefore, staining with BV421 Annexin V is typically used in conjunction with a vital dye such as 7-Amino-Actinomycin (7-AAD) to allow the investigator to identify early apoptotic cells (BV421 Annexin V positive, 7-AAD negative). Viable cells with intact membranes exclude 7-AAD, whereas the membranes of dead and damaged cells are permeable to the nucleic acid dye, 7-AAD. For example, cells that are considered viable are both BV421 Annexin V negative and 7-AAD negative while cells that are in early apoptosis are BV421 Annexin V positive and 7-AAD negative. Cells that are in late apoptosis or already dead are both BV421 Annexin V positive and 7-AAD positive. This assay does not distinguish between cells that have undergone apoptotic death versus those that have died as a result of a necrotic pathway because in either case, the dead cells will stain with both BV421 Annexin V and 7-AAD. However, when apoptosis is measured over time, cells can be often tracked from being BV421 Annexin V negative and 7-AAD negative (viable, or no measurable apoptosis), to BV421 Annexin V positive and 7-AAD negative (early apoptosis, membrane integrity is present), and finally to BV421 Annexin V positive and 7-AAD positive (end stage apoptosis and death). The movement of cells through these three stages suggests apoptosis. In contrast, a single observation indicating that cells are both BV421 Annexin V and 7-AAD positive, by itself reveals less information about the process by which the cells underwent their demise.
The Annexin V was conjugated to BD Horizon BV421 which is part of the BD Horizon Brilliant™ Violet family of dyes. With an Ex Max of 407-nm and Em Max at 421-nm, BD Horizon BV421 can be excited by the violet laser and detected in the standard Pacific Blue™ filter set (eg, 450/50-nm filter). BD Horizon BV421 conjugates are very bright, often exhibiting a 10 fold improvement in brightness compared to Pacific Blue conjugates.
When compensating dyes in this spectral range, the most accurate compensation can be obtained using unstained and single color-stained cellular controls.
BV421 is a polymer-based dye excited by the violet laser and is one of the brightest fluorochromes offered by BD Biosciences. Conjugates are typically 10 times brighter than Pacific Blue™ conjugates and are often as bright as or brighter than PE conjugates. Due to nearly identical excitation and emission properties but different spillover characteristics, BD Horizon BV421, Pacific Blue™, and BD Horizon™ V450 cannot be used simultaneously.
温馨提示:因厂家更改产品包装、产地或者更换随机附件等没有任何提前通知,且每位咨询者购买情况、提问时间等不同,为此以下回复仅对提问者3天内有效,其他网友仅供参考!若由此给您带来不便请多多谅解,谢谢!
服务热线
0771-3293894