Alcelaphine herpesvirus 1 (AlHV-1) is carried by wildebeest asymptomatically. It causes a fatal lymphoproliferative disease named wildebeest-derived malignant catarrhal fever (WD-MCF) when cross-species transmitted to a variety of susceptible species of the Artiodactyla order. WD-MCF can be reproduced experimentally in rabbits. In a previous report, we demonstrated that WD-MCF induced by AlHV-1...

Lymphoid organ-resident DC subsets are thought to play unique roles in determining the fate of T cell responses. Recent studies focusing on a single lymphoid organ identified molecular pathways that are differentially operative in each DC subset and led to the assumption that a given DC subset would more or less exhibit the same genomic and functional profiles throughout the body. Whether the l...

CCR7, along with L-selectin and LFA-1, mediates homing of T cells to secondary lymphoid organs via high endothelial venules (HEV). CCR7 has also been implicated in microenvironmental positioning of lymphocytes within secondary lymphoid organs and in return of lymphocytes and dendritic cells to the lymph after passage through nonlymphoid tissues. We have generated mAbs to human CCR7, whose speci...

Immune responses are initiated in the T-cell areas of secondary lymphoid organs where naïve T lymphocytes encounter dendritic cells (DCs) that present antigens taken up in peripheral tissues. DCs represent the interface between the universe of foreign and tissue-specific antigens and T lymphocytes, and they are the key players in the regulation of cell-mediated immunity. We discuss how the natu...

Typical T and B lymphocytes in the secondary lymphoid organs are long-lived cells that are selected from a large pool of short-lived precursor cells in the primary lymphoid organs. The bulk of mature T and B cells are immunologically naive and remain in interphase for prolonged periods. Contact with specific antigen causes these naive cells to proliferate rapidly and differentiate into a mixtur...

Both interdigitating cell sarcoma (IDCS) and follicular dendritic cell sarcoma (FDCS) are rare neoplasms derived from dendritic cells in lymphoid organs. IDCS is defined as a neoplastic proliferation of spindle-shaped to ovoid cells with phenotypic features similar to those of IDCs. FDCS is a malignant neoplasm derived from FDCs that possess and present antigens to B cells in the follicular (ge...

The migration of antigen-specific T cells to nonlymphoid tissues is thought to be important for the elimination of foreign antigens from the body. Here, we review the evidence that naive CD4(+) T cells are first activated by antigen presentation in secondary lymphoid organs, proliferate, and differentiate into effector cells capable of producing antimicrobial lymphokines. These effector cells t...

New preparations, fluorescent probes and imaging techniques are providing the means to observe the behavior of cells in the tissue environment of lymphoid organs. In particular, when combined with two-photon laser microscopy, intravital imaging of surgically exposed lymph nodes provides a unique view of lymphocyte migration and antigen presentation as it occurs within the living animal. The vie...

Mouse mammary tumor virus is known to infect newborn mice via mother's milk. A proposed key step for viral spread to the mammary gland is by the infection of lymphocytes. We show here that although in suckling mice retroviral proteins are found in all epithelial cells of the gut, viral DNA is exclusively detectable in the Peyer's patches. As early as 5 d after birth the infection leads to a sup...

Tumors of the spleen are rare compared to the incidence of such tumors in other parenchymatous organs. Their classification has varied with both time and author. They can be divided into two main categories: nonlymphoid and lymphoid. The most common nonlymphoid tumors are the vascular tumors which include benign and malignant haemangiomas, littoral cell angiomas, lymphangiomas and haemangioendo...