An Examination of the Development and Localization of Key Immune Cells in Developing Pouch Young of the Red-Tailed Phascogale (Phascogale calura).

Cells expressing the surface markers CD3, CD4, CD79b, IgM, MHC class II, and ModoUG (nonclassical MHC class I) were detected in red-tailed phascogale tissues using immunohistochemistry, and the appearance and localization of cells observed here was consistent with previous observations in other marsupial species. CD3 cells were first detected at one day postpartum (dpp) in the thymus, followed by ModoUG cells at 5-7 dpp in the thymus and lymph nodes. CD79b cells were first detected at 12-14 dpp in bone marrow, spleen, and lymph nodes.

Molecular identification and gene expression profiles of the T cell receptors and co-receptors in developing red-tailed phascogale (Phascogale calura) pouch young.

Expressed coding sequences were identified for the T cell receptors TCRα, TCRβ, TCRγ, TCRδ, TCRμ, and co-receptors CD3ε, CD4, and CD8α in the red-tailed phascogale (Phascogale calura). Expression of these genes was examined in the developing thymus and spleen of pouch young and juvenile individuals to detect any changes in expressionrelative to developmental stages. Transcripts of CD3ε, CD4, TCRδ and TCRμ were first detected in the thorax at 1 day postpartum (dpp), and transcripts of all target genes were detected in the thymus from 3 dpp, and the spleen from 17 dpp.

Identification of the mRNA encoding interleukin-6 and its receptor, interleukin-6 receptor α, in five marsupial species.

Expressed coding sequences for interleukin-6 (IL-6) and interleukin-6 receptor α (IL-6R) were examined in five marsupial species. Full length expressed coding sequences for IL-6 and IL-6R were identified and characterized in the gray short-tailed opossum (Monodelphis domestica). For IL-6, ∼225 bp fragments of the mRNA sequence were identified in the red-tailed phascogale (Phascogale calura), kultarr (Antechinomys laniger), and stripe-faced dunnart (Sminthopsis macroura), while ∼563 bp fragments of mRNA encoding IL-6R were identified in the red-tailed phascogale, kultarr, stripe-face dunnart and fat-tailed dunnart (Sminthopsis crassicaudata).

Histological Development of the Immune Tissues of a Marsupial, the Red-Tailed Phascogale (Phascogale calura).

Red-tailed phascogale (Phascogale calura) pouch young at birth were relatively underdeveloped in comparison with their eutherian counterparts, and the lymphoid tissues of the immune system were found to be histologically immature. The phascogale thymus rapidly developed in the first few days of pouch life and was quickly populated with lymphocytes. By the end of pouch life, involution of the thymus was underway.

The development of the immune tissues in marsupial pouch young.

Current knowledge of the development of the marsupial immune system, particularly in the context of lymphoid tissue development and the appearance of lymphocytes, has been examined and limitations identified. While primary lymphoid tissues like the thymus have been extensively studied, secondary lymphoid tissues such as the spleen and lymph nodes have been examined to a lesser extent, partly due to the difficulty of macroscopically identifying these structures, particularly in very small neonates. In addition, little research has been conducted on the mucosal-associated lymphoid tissues; tissues that directly trap antigens and play an important role in the maturity of adaptive immune responses.