Report of the Second Equine Leucocyte Antigen Workshop, Squaw valley, California, July 1995.

The final assignment of antibody clusters for leucocyte antigens and immunoglobulins, as described in detail in Sections 3 and 4, is summarized in Table 4. Together with other mAbs developed outside of ELAW II (Table 9) this pool of reagents represent a powerful array of tools for the study of equine immunity. The Second Equine Leucocyte Antigen Workshop made considerable advances in pursuing the objectives of establishing the specificities of mAbs and achieving consensus on the nomenclature for equine leucocyte and immunoglobulin molecules. Of equal importance, several productive collaborations were fostered among the participating laboratories and observers. Overall, enormous advances have been made in the past decade since mAbs specific for equine leucocyte antigens and immunoglobulins were first reported. There remains enormous scope and need for further studies of equine leucocyte antigens and immunoglobulins, both for the purposes of comparative immunology and for the good of the horse. In the future novel techniques will be required to develop reagents for specific target antigens such as the orthologues of the CD25 or CD45 isoforms. In studies of equine immunoglobulins the functional role of the IgG isotypes must be better established, reagents for IgE must be developed, and cloning of the immunoglobulin heavy chain genes will be essential if the complexities of the IgG sub-isotypes are to be elucidated. The tasks still facing the currently small group of equine immunologists throughout the world remain formidable, and will only be tackled successfully in a spirit of collaboration.

Anti-alpha chain monoclonal antibodies of equine MHC class-II antigens: applications to equine infectious anaemia.

This paper describes the characteristics of a monoclonal antibody (mAb), 6B11C3, that recognises most equine monocytic cells, as well as B- and T-lymphocytes. The T CD4+ and T CD8+ of this latter population are also stained by the 6B11C3 mAb. On the basis of the distribution of membrane antigens on these cell populations, and of immunohistochemistry results, this mAb appears to be an anti-equine class-II major histocompatibility complex (MHC) antigen. In horses, the hyperexpression of the MHC class-II antigen on T cells is an indication of activated lymphocytes. A decrease in the percentage of lymphocytes stained by 6B11C3 was observed in horses with persistent equine infectious anaemia.

Identification of canine T lymphocytes by membrane receptor to peanut agglutinin: T-lymphocyte identification in dogs with lupus-like syndrome.

Canine T lymphocytes were detected, using fluorescent peanut agglutinin (PNA) as a marker. Using a fluorescent technique and cytofluorometry, 70 +/- 11% and 72.4%, respectively, of peripheral blood lymphocytes were bound to PNA. Of thymocytes, 97 +/- 4.5% were detected by fluorescent PNA, but less than 1% were detected for lymphocytes from bone marrow. The T-lymphocyte depletion and enrichment indicated that PNA was bound to lymphocytes recognized by anti-T-lymphocyte heterologous serum. A T-lymphocyte deficiency was detected among 8 dogs with a lupus-like syndrome.