Anti-Human/Mouse/Rat CD8a [Clone C8/144B] – Purified (PhenoCycler-Fusion (CODEX)® Ready)

Clone C8/144B has been validated for use on PhenoCycler® using [Mouse/Human] [Tissue] [Tissue Type either FFPE or FF] tissue.

Synthetic peptide (the 13 C-terminal residues of the cytoplasmic domain of human CD8a)

This purified antibody is formulated in 0.01 M phosphate buffered saline (150 mM NaCl) PBS pH 7.4.

This antibody is stable for at least one week when stored at 2-8°C. For long term storage, aliquot in working volumes without diluting and store at -20°C in a manual defrost freezer. Avoid Repeated Freeze Thaw Cycles.

Anti-Human CD8a

CD8a is a membrane-bound glycoprotein found on the surface of cytotoxic T cells, where it serves as a co-receptor for major histocompatibility complex I (MHC I) alongside the T cell receptor (TCR). Cytotoxic T cells are critical immune effector cells, playing a role in pathogen detection, cancer, and autoimmunity, among others. As a monomer, CD8a has a predicted mass of ~26kDa, but its extensive glycosylation increases its apparent molecular weight to ~33kDa on SDS-PAGE.

Typically, CD8a forms a heterodimer with CD8b and triggers an activation cascade upon TCR binding to antigen-presenting MHC molecules, though it can homodimerize on certain immune cell subtypes and act as a negative regulator of TCR signaling (1,2). Dimeric forms of CD8 contain several domains, including the ectodomain, the hinge, the transmembrane domain, and the cytoplasmic tail (3). These domains include highly conserved sites, with 24 fully conserved residues across human, mouse, and rat, along with dog, bovine, chicken, rhesus, and fish (3). Outside of these sites, sequences across species share only 20-60% sequence similarity (3).

The hybridoma C8/144B was specifically developed for use in paraffin-embedded tissue samples, targeting the generally non-glycosylated/linear conformation cytoplasmic domain of CD8a (4). A peptide corresponding to the 13 C-terminal amino acids of CD8a was used to immunize BALB/c mice (4). C8/144B has been used in IHC and flow cytometry applications (4,5).

MHC class I

P01732

1. Ellmeier, W., Sunshine, M. J., Maschek, R., & Littman, D. R. (2002). Combined deletion of CD8 locus cis-regulatory elements affects initiation but not maintenance of CD8 expression. Immunity, 16(5), 623-634.

2. Cheroutre, H., & Lambolez, F. (2008). Doubting the TCR coreceptor function of CD8alphaalpha. Immunity, 28(2), 149–159.

3. Srinivasan S, Zhu C and McShan AC (2024) Structure, function, and immunomodulation of the CD8 co-receptor. Front. Immunol. 15:1412513.

4. Mason, D. Y., Cordell, J. L., Gaulard, P., Tse, A. G., & Brown, M. H. (1992). Immunohistological detection of human cytotoxic/suppressor T cells using antibodies to a CD8 peptide sequence. Journal of clinical pathology, 45(12), 1084–1088.

5. Cords, L., Engler, S., Haberecker, M., Rüschoff, J. H., Moch, H., de Souza, N., & Bodenmiller, B. (2024). Cancer-associated fibroblast phenotypes are associated with patient outcome in non-small cell lung cancer. Cancer cell, 42(3), 396–412.e5.