Human Leukocyte Differentiation Antigen workshop

Clusters of differentiation (CD antigens) mediate many of the interactions between the immune system and antigens, between components of the immune system, and between the immune system and other physiological systems, such as the nervous system. Studies of immunity and diseases of the immune system have been greatly facilitated over the last 20 years by the HLDA Workshops which have used antibodies to characterise many of the molecules involved in immunological processes, and have provided a nomenclature system, the CD system, which is used universally. The recent completion of the latest HLDA Workshop, the 10th, provides an opportunity to reflect on what has been achieved, what remains to be achieved, and how best to progress the field in the current state of biology.

The first HLDA Workshop provided a solution to these issues by organising multi-laboratory, blind, comparative analyses of CD antigens. Statistical analysis of data from several laboratories covering a number of cell types revealed "clusters of differentiation" (named for the statistical procedure of cluster analysis, and the focus on leucocyte differentiation), and immunochemical data provided supporting data in some cases. Antibodies thought to be detecting the same molecule, and the molecule itself, were given a "CD" designation. It would be difficult to exagger-ate the importance of this process at the time – it brought order to a chaotic field.

First, HLDA established a nomenclature and validation process that achieved order and confidence in the use of Workshop-classified antibodies. Researchers wanting to buy an antibody against a particular cluster of differentiation are well advised to buy one that has been validated by the HLDA Workshops. There are numerous examples of antibodies submitted as being against a particular CD turning out to be wrongly assigned by the submitters, and an antibody should not be referred to as being CD## unless this has been validated by the HLDA Workshops..

Second, HLDA has provided a major forum for discussion and experimentation in the field of leucocyte molecules, and fostered a collaborative spirit of exchange of reagents and information.

Third, many of our major research, diagnostic and now therapeutic targets and antibodies derive from the HLDA Workshops – CD3 and CD20 provide important examples.

Summary of the HLDA Workshops

Workshop Host Time CDs assigned Number of CDs assigned
HLDA 1 Pairs 1982 CD1-w15 15
HLDA 2 Boston 1984 CD16-w26 11
HLDA 3 Oxford 1987 CD27-45 19
HLDA 4 Vienna 1989 CD46-w78 35
HLDA 5 Boston 1993 CD79-w109 62
HLDA 6 Kobe 1996 CD110-166 52
HLDA 7 Harrogate 2000 CD167-247 81
HLDA 8 Adelaide 2004 CD248-339 93
HLDA 9 Barcelona 2010 CD340-364 20
HLDA 10 Wollongong 2014 CD365-371 7

Human Leukocyte Differentiation Antigen workshop: Reference

1. Bernard AR, Boumsell L, Dausset J, et al. eds. Leucocyte Typing: Human Leucocyte Differentiation Antigens Detected by Monoclonal antibodies. Berlin: Springer-Verlag, 1984.
2. Reinherz EL, Haynes BF, Nadler L, Bernstein ID, eds. Leukocyte Typing II. New York: Springer-Verlag, 1985.
3. McMichael AJ, Beverley PCL, Cobbold S, et al. eds. Leucocyte Typing III. White Cell Differentiation Antigens. Oxford: Oxford University Press, 1987.
4. Knapp W, Dorken B, Gilks W et al., eds. Leucocyte Typing IV. Oxford: Oxford University Press, 1989.
5. Schlossman SF, Boumsell L, Gilks W, et al. eds. Leucocyte Typing V: White cell differentiation antigens. Oxford: Oxford University Press, 1995.
6. Kishimoto T, Kikutani H, von dem Born AEGK, et al. eds. Leucocyte Typing VI. New York: Garland Publishing, Inc., 1997.
7. Mason D, Andre P, Bensussan A, et al. eds. Leucocyte Typing VII. Oxford: Oxford University Press, 2002.
8. Zola H, Swart B, Nicholson I, et al. CD molecules 2005: human cell differentiation molecules. Blood 2005. July 14 DOI 10.1182/blood-2005-03-1338.