Invitrogen™ CD8 Monoclonal Antibody (3B5), Pacific Blue™

Description

For fluorochrome conjugated antibodies only, light exposure should be avoided. Use dim light during handling, incubation with cells, and prior to analysis. It is recommended that cells be analyzed within 18 hours of staining. If the reagent is being diluted, it is recommended that only the quantity to be used within one week be diluted. Each lot is tested by flow cytometry using human peripheral blood leukocytes (PBL). Based on this testing it is recommended that 5 μL of antibody be used per 1 x 10^6 cells in a 100 μL staining volume.

CD8, also known as cluster of differentiation 8, is a type I transmembrane glycoprotein of the immunoglobulin family that plays a crucial role in T cell differentiation, activation, and signal transduction. It is expressed as either a heterodimer (CD8 alpha beta) or a homodimer (CD8 alpha alpha). The CD8 alpha beta form is predominantly found on the majority of thymocytes and a subpopulation of mature alpha beta TCR T cells, while the CD8 alpha alpha form is expressed on gamma delta TCR T cells, a subset of intestinal intraepithelial lymphocytes (IELs), and dendritic cells. CD8 functions as a co-receptor for major histocompatibility complex class I (MHC-I) molecules, working alongside the T cell receptor (TCR). The CD8 alpha chain is essential for binding to MHC-I. CD8 is also expressed on a subset of T cells, NK cells, monocytes, and dendritic cells as disulfide-linked homodimers of CD8 alpha. Upon ligation of MHC-I/peptide complexes presented by antigen-presenting cells (APCs), CD8 recruits lymphocyte-specific protein tyrosine kinase (Lck), leading to lymphokine production, increased motility, and activation of cytotoxic T lymphocytes (CTLs). Activated CTLs are vital for clearing pathogens and tumor cells. The differentiation of naive CD8+ T cells into CTLs is strongly enhanced by cytokines such as IL-2, IL-12, and TGF-beta1. Through its interactions with MHC-I and association with protein tyrosine kinase p56lck, CD8 plays a significant role in T cell development and the activation of mature T cells.