BD carries a variety of antibodies against many antigens and CD markers for use in a number of applications, including flow cytometry, immunofluorescence and immunohistochemistry. Cell populations can be characterized by antigen and CD marker expression; expression is denoted with a + or – or the words “high,” “mid” or “low” if more granular notation is needed. Antigens may be organized using CD marker nomenclature if they have been workshopped by the Human Cell Differentiation Molecule (HCDM) organization.1 Learn more about featured clones and their target antigens below.
Antigens
Antigens are molecules that can induce an adaptive immune response. Antigen specificity is the ability of the immune system to precisely recognize unique antigens. Antibodies and TCRs are the primary cellular components that confer antigen specificity. Both have a variable domain that allows for a wide variety of binding sites to be expressed; each binding site recognizes a unique antigen.1 Antigen specificity has been harnessed to develop a wide variety of antibodies that detect specific antigens in biological samples. Detection of specific antigens allows researchers to characterize, analyze and isolate cell subpopulations.
KLRG1
Killer cell lectin-like receptor G1 (KLRG1) is an immune marker encoded by the KLRG1 gene. It is an inhibitory lectin-like type II transmembrane receptor containing a cytoplasmic immunoreceptor tyrosine-based inhibitory motif (ITIM).2 KLRG1 is composed primarily of a homodimeric molecule consisting of two 30–38 kDa N-glycosylated subunits. BD carries several clones for the detection of KLRG1 in both human and mouse.
CD Markers
Cluster of differentiation (CD) is a nomenclature system for human leucocyte surface markers recognized by monoclonal antibodies. CD nomenclature is universally recognized by the scientific community and officially approved by the International Union of Immunological Societies. Due to the explosion of novel monoclonal antibodies developed by the international scientific community, this system was created in 1982 by the HCDM to organize the target antigens of these antibodies. Since multiple antibodies can be generated against the same antigen, the Workshops and Conferences on Human Leucocyte Differentiation Antigen (HLDA) acted as independent validation that differentiated and grouped antigens based on antibody binding.3
Characterized antigens are named as CD followed by an arbitrary number (e.g., CD45). A lowercase letter is added to differentiate molecules that share a common backbone (e.g., CD8a, CD8b). Currently, more than 370 CD molecules have been characterized.4 CD markers have now been expanded to encompass antigens on other species, intracellular antigens and antigens expressed by non-leucocyte cells. BD carries many clones recognized by the HLDA; the workshop number is indicated in the clone information when applicable.
CD56 (NCAM-1)
CD56 is also known as neural cell adhesion molecule 1 (NCAM-1), neural cell adhesion molecule (NCAM) or embryonic NCAM (E-NCAM).5 It is a member of the immunoglobulin superfamily and encoded by the gene NCAM1.6 CD56 plays important roles in the development of the immune and nervous systems. BD carries several clones appropriate for CD56 detection in human, non-human primates and mouse targets.
References
- About HCDM. https://www.hcdm.org/index.php/about-hcdm. Accessed July 8, 2022.
- Travers P, Walport M. Basic Concepts in Immunology. In: Janeway's Immunobiology. New York: Garland; 2008.
- Beyersdorf NB, Ding X, Karp K, Hanke T. Expression of inhibitory "killer cell lectin-like receptor G1" identifies unique subpopulations of effector and memory CD8 T cells. Eur J Immunol. 2001;31(12):3443-3452. doi:10.1002/1521-4141(200112)31:12<3443::aid-immu3443>3.0.co;2-j
- Clark G, Stockinger H, Balderas R, et al. Nomenclature of CD molecules from the tenth human leucocyte differentiation antigen workshop. Clin Transl Immunology. 2016;5(1). doi:10.1038/cti.2015.38
- Schlossman S. Leucocyte Typing V: White Cell Differentiation Antigens. Oxford: Oxford University Press; 1995.
- Lanier LL, Chang C, Azuma M, Ruitenberg JJ, Hemperly JJ, Phillips JH. Molecular and functional analysis of human natural killer cell-associated neural cell adhesion molecule (N-CAM/CD56). J Immunol. 1991;146(12):4421-4426.
