Description

PA007381.r2b: In vivo Grade Recombinant Anti-mouse CD8a Monoclonal Antibody, Rat IgG2b Kappa (Clone: YTS 105.18)

The rat anti-mouse CD8a monoclonal antibody YTS 105.18 (rat IgG2b kappa) reacts with the mouse CD8a protein (T-cell surface glycoprotein CD8 alpha chain) encoded by the mouse CD8A gene that encodes the CD8a chain of the dimeric CD8 protein. The mouse CD8 protein is primarily responsible for cell-mediated immune defense and T-cell development. CD8A has been widely reported as a potential prognosis and diagnostic marker for several diseases, such as inflammatory disorders and tumors. YTS 105.18 is a rat IgG2b anti-CD8a monoclonal antibody that does not deplete CD8+ T-cells in vivo and is widely used for the blockade of CD8+ T-cell activity in mice. Inoculation of mice with YTS 105.18 induces tolerance to zenograft transplantation and reduces insulin-dependent diabetes mellitus (IDDM) in NOD mice.

Some suppliers and researchers state that YTS 105.18 is a rat IgG2a monoclonal antibody. Its sequence of the heavy chain indicates that it is a rat IgG2b antibody.

Our recombinant YTS 105.18 antibodies have a part (variable regions) or complete amino acid sequences of the rat anti-mouse CD8a monoclonal antibody (hybridoma clone name or number: YTS 105.18).

Citations of Syd Labs Anti-Mouse CD8a Monoclonal Antibody:

1、Potential treatment benefits of a GLP-1R antagonist in combination with immune checkpoint inhibitors in colorectal cancer
Chen F, et al. Oncol Lett. 2026 Feb 10;31(4):132. doi: 10.3892/ol.2026.15485. PMID: 41728352; PMCID: PMC12917479.
“Immunohistochemistry (IHC)：Excised mouse or patient tumor tissues were fixed in 10% neutral-buffered formalin for 24 h at room temperature and processed for paraffin embedding …… For the detection of the intracellular/membrane protein GLP-1R, sections were permeabilized with 0.1% Triton X-100 in PBS for 10 min at room temperature. Blocking was performed with 5% normal goat serum …… for 30 min at room temperature and the sections were incubated overnight at 4°C with a primary anti-CD8 (cat. no. PA007381.r2b; Syd Labs) or anti-GLP-1R antibody …… diluted 1:100 in blocking solution. After three washes in PBS, a biotinylated goat anti-mouse IgG secondary antibody …… was applied for 1 h at room temperature …… Quantitative analysis of IHC staining was performed using the Alpathwell Pathology Image Analysis System.”

References For Anti-Mouse CD8a Monoclonal Antibody (Clone YTS 105.18):

1. Structure, function, and immunomodulation of the CD8 co-receptor
Shreyaa Srinivasan,et al.Front Immunol. 2024.PMCID: PMC11381289
“Expressed on the surface of CD8+ T cells, the CD8 co-receptor is a key component of the T cells that contributes to antigen recognition, immune cell maturation, and immune cell signaling. While CD8 is widely recognized as a co-stimulatory molecule for conventional CD8+ αβ T cells, recent reports highlight its multifaceted role in both adaptive and innate immune responses. In this review, we discuss the utility of CD8 in relation to its immunomodulatory properties. We outline the unique structure and function of different CD8 domains (ectodomain, hinge, transmembrane, cytoplasmic tail) in the context of the distinct properties of CD8αα homodimers and CD8αβ heterodimers. We discuss CD8 features commonly used to construct chimeric antigen receptors for immunotherapy. We describe the molecular interactions of CD8 with classical MHC-I, non-classical MHCs, and Lck partners involved in T cell signaling. Engineered and naturally occurring CD8 mutations that alter immune responses are discussed. The applications of anti-CD8 monoclonal antibodies (mABs) that target CD8 are summarized. Finally, we examine the unique structure and function of several CD8/mAB complexes. Collectively, these findings reveal the promising immunomodulatory properties of CD8 and CD8 binding partners, not only to uncover basic immune system function, but to advance efforts towards translational research for targeted immunotherapy.”

2. Type 1 Diabetes Development Requires Both CD4+ and CD8+ T cells and Can Be Reversed by Non-Depleting Antibodies Targeting Both T Cell Populations
Jenny M. Phillips,et al.Rev Diabet Stud. 2009 Summer.PMCID: PMC2779016
“Type 1 diabetes development in NOD mice appears to require both CD4+ and CD8+ T cells. However, there are some situations where it has been suggested that either CD4+ or CD8+ T cells are able to mediate diabetes in the absence of the other population. In the case of transgenic mice, this may reflect the numbers of antigen-specific T cells able to access the pancreas and recruit other cell types such as macrophages leading to a release of high concentrations of damaging cytokines. Previous studies examining the requirement for CD8+ T cells have used antibodies specific for CD8α. It is known that CD8α is expressed not only on αβ T cells, but also on other cell types, including a DC population that may be critical for presenting islet antigen in the pancreatic draining lymph nodes. Therefore, we have re-examined the need for both CD4+ and CD8+ T cell populations in diabetes development in NOD mice using an antibody to CD8β. Our studies indicate that by using highly purified populations of T cells and antibodies specific for CD8+ T cells, there is indeed a need for both cell types. In accordance with some other reports, we found that CD4+ T cells appeared to be able to access the pancreas more readily than CD8+ T cells. Despite the ability of CD4+ T cells to recruit CD11b class II positive cells, diabetes did not develop in the absence of CD8+ T cells. These studies support the observation that CD8+ T cells may be final effector cells. As both T cell populations are clearly implicated in diabetes development, we have used a combination of non-depleting antibodies to target both CD4-positive and CD8-positive cells and found that this antibody combination was able to reverse diabetes onset in NOD mice as effectively as anti-CD3 antibodies.”

3. Universal CAR T cells targeted to HER2 with a biotin-trastuzumab soluble linker penetrate spheroids and large tumor xenografts that are inherently resistant to trastuzumab mediated ADCC
Lőrinc Nagy,et al.Front Immunol. 2024.PMCID: PMC10982377
“CAR T cell therapies face challenges in combating solid tumors due to their single-target approach, which becomes ineffective if the targeted antigen is absent or lost. Universal CAR T cells (UniCAR Ts) provide a promising solution by utilizing molecular tags (linkers), such as biotin conjugated to monoclonal antibodies, enabling them to target a variety of tumor antigens. Recently, we showed that conventional CAR T cells could penetrate the extracellular matrix (ECM) of ADCC-resistant tumors, which forms a barrier to therapeutic antibodies. This finding led us to investigate whether UniCAR T cells, targeted by soluble antibody-derived linkers, could similarly tackle ADCC-resistant tumors where ECM restricts antibody penetration. We engineered UniCAR T cells by incorporating a biotin-binding monomeric streptavidin 2 (mSA2) domain for targeting HER2 via biotinylated trastuzumab (BT). The activation and cytotoxicity of UniCAR T cells in the presence or absence of BT were evaluated in conventional immunoassays. A 3D spheroid coculture was set up to test the capability of UniCAR Ts to access ECM-masked HER2+ cells. For in vivo analysis, we utilized a HER2+ xenograft model in which intravenously administered UniCAR T cells were supplemented with intraperitoneal BT treatments. In vitro, BT-guided UniCAR T cells showed effective activation and distinct anti-tumor response. Upon target recognition, IFNγ secretion correlated with BT concentration. In the presence of BT, UniCAR T cells effectively penetrated HER2+ spheroids and induced cell death in their core regions. In vivo, upon intravenous administration of UniCAR Ts, circulating BT linkers immediately engaged the mSA2 domain and directed effector cells to the HER2+ tumors. However, these co-treated mice died early, possibly due to the lung infiltration of UniCAR T cells that could recognize both native biotin and HER2. Our results suggest that UniCAR T cells guided with soluble linkers present a viable alternative to conventional CAR T cells, especially for patients resistant to antibody therapy and those with solid tumors exhibiting high antigenic variability. Critical to their success, however, is the choice of an appropriate binding domain for the CAR and the corresponding soluble linker, ensuring both efficacy and safety in therapeutic applications.”

Related Recombinant IgG Reference Antibodies:
In vivo grade recombinant rat IgG2b isotype control antibody

Syd Labs provides the following recombinant anti-human CD8a monoclonal antibodies:
In vivo grade recombinant anti-human CD8a antibodies (clone OKT8)
Recombinant anti-human CD8a antibodies (clone OKT8) for flow cytometry

Syd Labs provides the following recombinant anti-mouse CD8a monoclonal antibodies:
In vivo grade recombinant anti-mouse CD8a antibodies (clone 2.43)
In vivo grade recombinant anti-mouse CD8a antibodies (clone YTS 169.4)
In vivo grade recombinant anti-mouse CD8a antibodies (clone YTS 105.18)

Syd Labs provides the following recombinant anti-mouse CD8b monoclonal antibodies:
In vivo grade recombinant anti-mouse CD8b antibodies (clone YTS 156.7)

Anti-Mouse CD8a Antibody (YTS 105.18) from: In Vivo Grade Recombinant Anti-Mouse CD8a Monoclonal Antibody (Clone YTS 105.18), Rat IgG2b Kappa: PA007381.r2b Syd Labs