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1 minute
The distribution of the functional subsets of porcine T cells, the cytolytic/suppressor (Tc/s) and the helper/inducer (Th/i) cells was studied in cryostat sections of thymus, lymph nodes, tonsils, Peyer's patches, spleen and liver using the indirect immunoperoxidase technique. Three murine monoclonal antibodies (mAb) were used. The mAb 8/1 reacts with an antigen present on all T cells and on cells of the myeloid lineage; the antigen has not yet been characterized biochemically. The mAb 295/33 (anti-T8) binds to the porcine T8 antigen and defines the Tc/s subset, while mAb PT-4 (anti-T4) detects the porcine T4 antigen and defines the Th/i subset. Practically all thymocytes were stained by mAb 8/1. The majority of cortical thymocytes apparently co-expressed T8 and T4, whereas distinct fractions of medullary cells were labelled by either anti-T8 or anti-T4. In peripheral lymphoid organs all three mAb reacted with cells in the thymus-dependent areas and with cells scattered in the lymphoid follicles. In lymph nodes, tonsils and Peyer's patches, anti-T8 and anti-T4 each labelled approximately half of the cells stained by mAb 8/1. In the periarteriolar lymphoid sheath of the spleen, anti-T4 labelled more cells than did anti-T8. The reactivity of mAb 8/1 with the Kupffer cells of the liver demonstrated the expression of the 8/1 antigen on cells of the monocyte lineage. The T8 and T4 antigens could not be detected in acetone-fixed and paraffin-embedded sections, while the antigen recognized by mAb 8/1 remained preserved. Altogether, despite an inverted microanatomical structure of porcine lymph nodes, the frequency and distribution of T8+ and T4+ cells in thymus-dependent areas proved to be similar to those found in other species.
1 minute
The expression of an antigen on porcine T lymphocytes detected by murine monoclonal antibody (mAb) 8/1 was investigated by functional studies and dual-parameter immunofluorescence. mAb 8/1 reacts with greater than 95% of thymocytes and in peripheral blood with all T lymphocytes and with cells of the monocyte/macrophage lineage, but not with B cells, erythrocytes, and platelets. Pretreatment of peripheral blood lymphocytes with mAb 8/1 plus complement abrogated the proliferative response in vitro to mitogen, soluble antigen, and MHC determinants. Dual-parameter immunofluorescence revealed that resting porcine T8+ as well as T4+ lymphocytes express the 8/1 antigen, whereas after in vitro activation, cell surface expression of the antigen was low or absent in both T cell subsets. Thus, the 8/1 antigen represents a marker that discriminates between resting and activated T lymphocytes. Distribution and functional criteria indicate that 8/1 represents a novel marker not described before for any other mammalian species.
1 minute
The existence of four subpopulations in resting porcine T lymphocytes is documented. In addition to the two known subpopulations which are typified by a mutually exclusive expression of either the CD8 or the CD4 differentiation antigen, CD4-CD8+ and CD4+CD8- T lymphocytes, respectively, two unusual subpopulations were prominent not only in peripheral blood, but also in lymphoid tissues: CD4-CD8- T lymphocytes expressing neither of these antigens and CD4+CD8+ T lymphocytes coexpressing both antigens. While CD4+CD8+ lymphoblasts have been found also in other species, resting T lymphocytes with that phenotype are without precedent among all species analyzed to date. This unique composition of the porcine T lymphocyte population has to be taken into consideration when the swine is used as a large animal model in experimental medicine.
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Die Universitätsbibliothek (UB) verfügt über ein umfangreiches Archiv an elektronischen Medien, das von Volltextsammlungen über Zeitungsarchive, Wörterbücher und Enzyklopädien bis hin zu ausführlichen Bibliographien und mehr als 1000 Datenbanken reicht. Auf iTunes U stellt die UB unter anderem eine Auswahl an elektronischen Publikationen der Wissenschaftlerinnen und Wissenschaftler an der LMU bereit. (Dies ist der 5. von 22 Teilen der Sammlung 'Medizin - Open Access LMU'.)

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