Deleterious effects of Echinacea purpurea and melatonin on myeloid cells in mouse spleen and bone marrow.

The neurohormone, melatonin, a product of the pineal gland, is a potent immune cell stimulant. Phytochemicals contained in root extracts of the plant species Echinacea purpurea are also potent as immune cell stimulants. Both agents are potent stimulants of T, B, and/or natural killer cells, but little is known of their effect on other hemopoietic cells, specifically granular leukocytes, also participants in a wide variety of disease defense processes. Given their current popularity and availability for amelioration of a) jet lag and sleep disorders (melatonin) and b) virus-mediated respiratory infections (E. purpurea), we investigated the effects of these agents on granular leukocytes and their precursors, myeloid cells. Mice received these agents daily for 7 or 14 days via the diet, thus mimicking human administration, after which spleens and bone marrow were removed and assessed for mature, differentiated granulocytes and their myeloid progenitors. The influence of these agents was directly related to the stage of cell maturity. Administration of both agents together resulted in significantly elevated levels of myeloid progenitor cells in both bone marrow and spleen and significantly reduced levels of mature, functional granulocyte progeny in both organs, suggesting a) increased precursor proliferation, b) antiapoptosis among the progenitors, and/or c) inhibition of precursor maturation-the latter readily explaining the paucity of mature granulocyte progeny. In conclusion, individual administration of either the herbal derivative and melatonin was either without effect (E. purpurea) or even advantageous (melatonin) to cells of this lineage, but when administered together, these agents significantly perturbed myelopoiesis.

Primary renal hypoplasia in humans and mice with PAX2 mutations: evidence of increased apoptosis in fetal kidneys of Pax2(1Neu) +/- mutant mice.

PAX2 mutations cause renal-coloboma syndrome (RCS), a rare multi-system developmental abnormality involving optic nerve colobomas and renal abnormalities. End-stage renal failure is common in RCS, but the mechanism by which PAX2 mutations lead to renal failure is unknown. PAX2 is a member of a family of developmental genes containing a highly conserved 'paired box' DNA-binding domain, and encodes a transcription factor expressed primarily during fetal development in the central nervous system, eye, ear and urogenital tract. Presently, the role of PAX2 during kidney development is poorly understood. To gain insight into the cause of renal abnormalities in patients with PAX2 mutations, kidney anomalies were analyzed in patients with RCS, including a large Brazilian kindred in whom a new PAX2 mutation was identified. In a total of 29 patients, renal hypoplasia was the most common congenital renal abnormality. To determine the direct effects of PAX2 mutations on kidney development fetal kidneys of mice carrying a Pax2 (1Neu)mutation were examined. At E15, heterozygous mutant kidneys were approximately 60% of the size of wild-type littermates, and the number of nephrons was strikingly reduced. Heterozygous 1Neu mice showed increased apoptotic cell death during fetal kidney development, but the increased apoptosis was not associated with random stochastic inactivation of Pax2 expression in mutant kidneys; Pax2 was shown to be biallelically expressed during kidney development. These findings support the notion that heterozygous mutations of PAX2 are associated with increased apoptosis and reduced branching of the ureteric bud, due to reduced PAX2 dosage during a critical window in kidney development.

Presence of the T-cell activation marker OX-40 on tumor infiltrating lymphocytes and draining lymph node cells from patients with melanoma and head and neck cancers.

BACKGROUND: The OX-40 antigen is a cell surface glycoprotein in the tumor necrosis factor receptor family that is expressed primarily on activated CD4+ T cells. Selective target organ expression of the OX-40 receptor on autoantigen specific T cells has been found in autoimmune disease. In order to evaluate whether OX-40 is expressed on T cells from patients with nodal-draining carcinomas, OX-40 expression was assessed in tumor infiltrating lymphocytes (TILs), draining lymph node cells (DLNCs), and/or peripheral blood lymphocytes (PBLs) of 13 patients with head and neck squamous cell carcinomas and 9 patients with melanomas. METHODS: Cell phenotype was determined by fluorescence cell analysis using a monoclonal antibody to human OX-40, and CD4+ T cell lymphokine production was determined by reverse transcriptase-polymerase chain reaction (RT-PCR). RESULTS: Expression of the OX-40 receptor was found in as many as 31% of the TILs and as many as 28% of the DLNCs tested. Conversely, no OX-40 expression was found in PBLs. In addition, CD4+ T cells isolated from DLNCs (but not from TILs or PBLs) secreted a Th1 pattern of cytokines (IL-2, gamma interferon). Co-culture of autologous CD4+ TILs with an MHC class II+ melanoma cell line transfected with OX-40 ligand cDNA resulted in T cell proliferation and in vitro tumor regression. CONCLUSIONS: These findings suggest that OX-40+ CD4+ T cells isolated from tumors and their adjacent draining nodes may represent a tumor-specific population of activated T cells capable of mediating tumor reactivity. These cells may play an exploitable role in future trials of immunotherapy.