PubMed · 6672322
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
T Kobari, S Tada, K Kaneko. 1983. [Cholecystography].. https://pubmed.ncbi.nlm.nih.gov/6672322/
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
CD40 ligand (CD40L) gene-disrupted (CD40L-/-) mice were employed to examine the role of costimulatory signals via CD40L-CD40 interactions in mucosally induced tolerance. CD40L-/- and control (CD40L+/+) mice of the same C57BL/6 x 129/J background were immunized orally with 25 mg of OVA before systemic challenge with OVA in CFA. While CD40L+/+ mice showed reductions in Ag-specific T cell responses including delayed-type hypersensitivity (DTH) and proliferative responses, CD40L-/- mice underwent normal T cell responses. Further, cytokine analysis of splenic CD4+ T cells showed that both Th1-type (e.g., IFN-gamma and IL-2) and Th2-type (e.g., IL-4, IL-5, IL-6, and IL-10) responses were maintained in CD40L-/- mice orally immunized with OVA, whereas these cytokine responses in CD40L+/+ mice were significantly reduced. In addition, splenic CD4+ T cells from CD40L-/- mice orally immunized with OVA provided B cell help in Ag-specific Ab-forming cells when the cells were cultured with naive B cells in the presence of Ag and CD40L-transfected cell lines. In contrast, an identical culture condition containing splenic CD4+ T cells from orally tolerized CD40L+/+ mice did not exhibit helper activity. Taken together, these findings indicate that CD40L and CD40 interactions are essential for the induction of systemic T cell unresponsiveness to orally administered Ag.
[2-14C]2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) was administered orally (304 ng/kg body-weight dose based upon an average 70-kg-body-weight subject) to 5 human colon-cancer patients (58 to 84 years old), as well as to F344 rats and B6C3F1 mice. Colon tissue was collected from the human subjects at surgery and from the rodents 3.5 to 6 hr after administration. Colon DNA-adduct levels and tissue available doses were measured by accelerator mass spectrometry (AMS). The mean levels of MeIQx in the histologically normal colon tissue were not different among the human (97 +/- 26 pg MeIQx/g), rat (133 +/- 15 pg/g) or mouse (78 +/- 10 pg/g) tissues; and no difference existed between the levels detected in human normal and tumor tissue (101 +/- 15 pg/g). Mean DNA-adduct levels in normal human colon (26 +/- 4 adducts/10(12) nucleotides) were significantly greater (p < 0.01) than in rats (17.1 +/- 1 adduct/10(12) nucleotides) or mice (20.6 +/- 0.9 adduct/10(12) nucleotides). No difference existed in adduct levels between normal and tumor tissue in humans. These results show that MeIQx forms DNA adducts in human colon at low dose, and that the human colon may be more sensitive to the effects of MeIQx than that of mice or rats.
Explore the source record for details and available documents.