Anti-Human CD8a [Clone OKT-8] — PE

Human T lymphocytes

This R-phycoerythrin (R-PE) conjugate is formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.4, 1% BSA and 0.09% sodium azide as a preservative.

Liquid

This R-phycoerythrin (R-PE) conjugate is stable when stored at 2-8°C. Do not freeze.

Research Use Only

2 – 8° C Wet Ice

Blue Laser (488 nm) and/or Green Laser (532 nm)/Yellow-Green Laser (561 nm)

OKT8 activity is directed against human CD8a.

CD8 is an integral membrane protein essential to immune response that acts as a co-receptor for the MHC class I molecule:peptide complex¹. CD8 recruits the Src kinase LCK to the vicinity of the TCR-CD3 complex, leading to the activation of cytotoxic T-lymphocytes which recognize and eliminate infected cells and tumor cells. CD8⁺ T cell differentiation is tightly regulated, and the T cell response depends on the antigen encounter. Immune response to acute infection, autoimmunity, graft vs host disease, tumors, chronic infection, and self-tolerance are all affected by CD8⁺ T cells².

CD8 molecules are either CD8α/CD8β heterodimers, when expressed on thymus-derived T cells, or they are CD8α homodimers, when expressed on intraepithelial lymphocytes from the gut, CD8⁺ dendritic cells³, or a subset of human natural killer cells⁴. Gene expression is closely regulated with CD4, with expression of CD4 and CD8 used to distinguish the four major stages of T cell development⁴.

OKT8 was generated by immunizing a CAF₁/J mouse with human T lymphocytes^5,6. Spleen cells were fused with P3X63Ag8.U1 myeloma cells and OKT8 was shown to be highly specific for human T cell populations by indirect immunofluorescence and C-mediated microcytotoxic assays. OKT8 can fix complement⁷.

CD8a is found on normal human cytotoxic/suppressor T lymphocytes and on about 80% of normal human thymocytes. CD8a is also expressed by a subset of natural killer cells, intraepithelial lymphocytes, monocytes, memory T cells, and dendritic cells.

CD8B, MHC class I HLA-A/B2M dimer

1. https://www.uniprot.org/uniprotkb/P01732/entry
2. Philip M, Schietinger A. Nat Rev Immunol. 22(4):209-223. 2022.
3. Kioussis D, Ellmeier W. Nat Rev Immunol. 2(12):909-919. 2002.
4. Ellmeier W, Haust L, Tschismarov R. Cell Mol Life Sci. 70(23):4537-4553. 2013.
5. Kung P, Goldstein G, Reinherz EL, et al. Science. 206(4416):347-349. 1979.
6. Thomas Y, Sosman J, Irigoyen O, et al. J Immunol. 125(6):2402-2408. 1980.
7. https://patents.google.com/patent/US4361550A/en
8. Kay HD, Horwitz DA. J Clin Invest. 66(4):847-851. 1980.
9. Callard RE, Smith CM, Worman C, et al. Clin Exp Immunol. 43(3):497-505. 1981.
10. Selby WS, Janossy G, Goldstein G, et al. Clin Exp Immunol. 44(3):453-458. 1981.
11. Berrih S, Gaud C, Bach MA, et al. Clin Exp Immunol. 45(1):1-8. 1981.
12. Clement M, Ladell K, Ekeruche-Makinde J, et al. J Immunol. 187(2):654-663. 2011.
13. Zhou Q, Schneider IC, Edes I, et al. Blood. 120(22):4334-4342. 2012.