Description
The M1/42 monoclonal antibody (mAb) specifically recognizes intact Histocompatibility-2 Region (H-2) class I antigens (Ags), also known as mouse Major Histocompatibility Complex class I (MHC-I) Ags. This mAb reportedly binds to one or more of the H-2 Ags (H-2K, H-2D, and likely H-2L) that are primarily expressed on most nucleated somatic cells of hematopoietic and nonhematopoietic origin. H-2 class I molecules are comprised of a ~45-50 kDa type I transmembrane heavy chain glycoprotein that is noncovalently linked to ~13 kDa β2-microglobulin (β2-m). The extracellular region of the polymorphic heavy chains is comprised of three globular domains (α1, α2, and α3), followed by a transmembrane region and a cytoplasmic tail. Sequence variations are manifest in regions of the α1 and α2 domains that line the peptide-binding cleft involved in Ag presentation. The M1/42 mAb reportedly binds to H-2 class I Ags from multiple mouse haplotypes including a, b, d, j, k, s, and u. It does not bind to separated H-2 class I heavy chains or β2-m. Cell surface CD8 molecules bind to invariant sites of the H-2 heavy chains and can provide coreceptor signaling for Ag-mediated activation through the T cell receptor. H-2 class I molecules that present self-Ags can lead to self-tolerance of maturing CD8+ T cells due to thymic selection. Alternatively, these molecules can present foreign peptide Ags to mature peripheral CD8+ T cells resulting in cell-mediated immune responses against foreign Ags. H-2 class I Ags also serve as ligands for activating and inhibitory receptors expressed by NK cells and some T cells. The M1/42 antibody is useful for analyzing H-2 class I Ag expression on cells or cell lines. Cells from different experimental systems, eg, stressed cells that have undergone infection or transformation, may express little or no H-2 class I Ag. In contrast, cells undergoing activation or responding to certain factors (eg, interferons) may express upregulated levels of these Ags.
Bead-based compensation or unmixing controls, such as BD® CompBeads or BD™ SpectraComp™, can be used as surrogates to assess fluorescence spillover when bound to fluorochrome-conjugated antibodies. Although these beads have spectral properties similar to cells, variations in spectral emission may occur, resulting in differing spillover values compared to biological controls. Therefore, it is considered best practice to compare the spillover obtained from cells and bead-based controls when using BD® CompBeads or BD™ SpectraComp™ for the first time, to ensure they are appropriate for the intended application.
Store undiluted at 4°C and protected from prolonged exposure to light. Do not freeze. The monoclonal antibody was purified from tissue culture supernatant or ascites by affinity chromatography. The antibody was conjugated to the dye under optimum conditions that minimize unconjugated dye and antibody.
1. Please refer to www.bdbiosciences.com/us/s/resources for technical protocols.
2. Please refer to http://regdocs.bd.com to access safety data sheets (SDS).
3. For U.S. patents that may apply, see bd.com/patents.
4. Caution: Sodium azide yields highly toxic hydrazoic acid under acidic conditions. Dilute azide compounds in running water before discarding to avoid accumulation of potentially explosive deposits in plumbing.
5. Since applications vary, each investigator should titrate the reagent to obtain optimal results.
6. The production process underwent stringent testing and validation to assure that it generates a high-quality conjugate with consistent performance and specific binding activity. However, verification testing has not been performed on all conjugate lots.
7. When using high concentrations of antibody, background binding of this dye to erythroid fragments produced by ammonium chloride-based lysis, such as with BD Pharm Lyse™ Lysing Buffer (Cat. No. 555899), has been observed when the antibody conjugate was present during the lysis procedure. This may cause nonspecific staining of target cells, such as leukocytes, which have bound the resulting erythroid fragments. This background can be mitigated by any of the following: titrating the antibody conjugate to a lower concentration, fixing samples with formaldehyde, or removing erythrocytes before staining (eg, gradient centrifugation or pre-lysis with wash). This background has not been observed when cells were lysed with BD FACS™ Lysing Solution (Cat. No. 349202) after staining.
8. For fluorochrome spectra and suitable instrument settings, please refer to our Multicolor Flow Cytometry web page at www.bdbiosciences.com/colors.
9. An isotype control should be used at the same concentration as the antibody of interest.
10. Cy is a trademark of Global Life Sciences Solutions Germany GmbH or an affiliate doing business as Cytiva.
11. Please observe the following precautions: We recommend that special precautions be taken (such as wrapping vials, tubes, or racks in aluminum foil) to protect exposure of conjugated reagents, including cells stained with those reagents, to any room illumination. Absorption of visible light can significantly affect the emission spectra and quantum yield of tandem fluorochrome conjugates.
12. Tandem fluorochromes contain both an energy donor and an energy acceptor. Although every effort is made to minimize the lot-to-lot variation in the efficiency of the fluorochrome energy transfer, differences in the residual emission from the donor may be observed. Additionally, multi-laser cytometers may directly excite both the donor and acceptor fluorochromes. Therefore, we recommend for every tandem conjugate, a matched individual single-stain control be acquired for generating a compensation or spectral unmixing matrix.
