Immune regulation has been shown to be involved in the progressive growth of some murine tumors. In this study, we demonstrated that a single in vivo administration of an amount less than 0.125 mg of anti-CD25 interleukin 2 receptor alpha monoclonal antibody (mAb; PC61) caused the regression of tumors that grew progressively in syngeneic mice. The tumors used were five leukemias, a myeloma, and...

During the past several years, much interest has been directed towards delineating and characterizing different subsets of T helper (Th) cells in order to understand their roles in immune processes. In this study, we report the generation of antigen-specific rat Th cell clones and their characterization in terms of phenotype, function, and lymphokine production. The clones were derived by cultu...

The interleukin-2 receptor (IL-2R) is composed of at least three cell surface subunits, IL-2R alpha, IL-2R beta, and IL-2R gamma c. On activated T-cells, the alpha- and beta-subunits exist as a preformed heterodimer that simultaneously captures the IL-2 ligand as the initial event in formation of the signaling complex. We used BIAcore to compare the binding of IL-2 to biosensor surfaces contain...

The interleukin-2 receptor alpha chain (IL-2Ra, CD25) plays a major part in shaping the dynamics of T cell populations following immune activation, due to its role in T cell proliferation and survival. Strategies to blunt the effector responses in transplantation have been developed by devising pharmaceutical agents to block the IL-2 pathways. However, such strategies could adversely affect the...

Several lines of evidence have revealed that ubiquitylation of membrane proteins serves as a signal for endosomal sorting into lysosomes or lytic vacuoles. The hepatocyte growth factor-regulated tyrosine kinase substrate (Hrs) interacts with ubiquitylated cargoes through its ubiquitin-interacting-motif domain (UIM domain), and plays an essential early role in endosomal sorting. Here, we show th...

CYTOKINES play critical roles in the immune response, particularly in the self-defense system. Activated human monocyte/macrophage is a major source of interleukin-6 (lL-6) and tumor necrosis factor-alpha (TNFa). I Interleukin-2 HL-2) is released primarily by activated T lymphocytes following antigen presentation.2 We conducted a study to monitor various cytokines (IL-6. TNF-a, and IL-2) after ...

Interleukin-2 (IL-2 or T cell growth factor) is a 14,500 daltons glycoprotein critically involved in the development of a normal human immune response [1, 2J. Recently, cDNA for this lymphokine has been isolated and expressed in both prokaryotic and eukaryotic cells [3-5J. Further, the human IL-2 gene has been cloned, sequenced [6], and localized to chromosome 4. As with other polypeptide hormo...

The 7-day cytotoxic lymphocytes (CTL) induced in mixed lymphocyte culture express only the chain of the interleukin-2 receptor (IL-2R). In the present study this fact has been confirmed in a murine semi-allogeneic system. The ability of low doses of mafosfamide (Mf) to affect IL-2-induced CTL proliferation has been demonstrated. It was also shown that IL-2 activated resting suppressor cells. Th...

Interleukin-2 (IL-2) is the major growth factor for activated T-lymphocytes and stimulates clonal expansion and maturation of these lymphocytes. IL-2 binds to its receptor complex, IL-2Ralpha, beta, and gamma chains, and exerts its effect via second messengers, mainly tyrosine kinases, which ultimately stimulate gene expression. The heterotrimerization of the receptor chains leads to high affin...

The interleukin 2 receptor alpha-chain (IL-2R alpha) gene is a key regulator of lymphocyte proliferation. IL-2R alpha is rapidly and potently induced in T cells in response to mitogenic stimuli. Interleukin 2 (IL-2) stimulates IL-2R alpha. transcription, thereby amplifying expression of its own high-affinity receptor. IL-2R alpha transcription is at least in part controlled by two positive regu...