Production of interferon gamma by peripheral blood mononuclear cells from normal subjects and from patients with rheumatoid arthritis

A radioimmunoassay for human interferon gamma (IFN-gamma) has been carried out using a recombinant glycosylated interferon (Hu IFN-gamma) as tracer, the N.I.H. reference preparation (Gg 23-901-530) and a polyclonal rabbit antiserum. The assay is highly specific for IFN-gamma: there is no cross-reaction either with interferons alpha and beta, Interleukins 1 and 2, tumor necrosis factor alpha and beta or with various brain peptides. The sequential saturation procedure allowed a sensitivity of 0.4 U/ml with intra and between assay coefficients of variation less than 8 and 12%, respectively. The in-vitro production of IFN-gamma by peripheral blood mononuclear cells (P.B.M.C.) was also measured. In unstimulated cultures, IFN-gamma production remained undetectable, i.e. below the 0.4 U/ml sensitivity level. After stimulation of P.B.M.C. from normal subjects with increasing amounts of PHA, both the 3H-thymidine incorporation and IFN-gamma release followed bell-shaped curves. There was no significant difference of 3H-thymidine incorporation between PHA stimulated cultures (0.2 and 2.5 ug/ml) from normal subjects (36 cases) and those with active (16 cases) or non-active (14 cases) rheumatoid arthritis. At two PHA concentrations of 0.2 and 2.5 ug/ml, mononuclear cells from patients with active disease produced significantly less IFN-gamma than those from either controls or cases with non-active disease

Adverse effect of abdominal operations on production of interferon-gamma.

peer reviewed[en] OBJECTIVE: To assess the effects of abdominal operations on the production of cytokines as one of the mechanisms of postoperative immunosuppression. DESIGN: Prospective study. SETTING: University hospital, Belgium. SUBJECTS: 19 Selected patients who underwent operations for benign (n = 10) or malignant (n = 9) diseases. INTERVENTIONS: Whole blood was collected in heparinised tubes before operation and on postoperative days 1, 2, 3, 5, 7, and 9. After 1/10 dilution in culture medium the whole blood cells were stimulated with 5 micrograms/ml phytohaemagglutinin and 25 micrograms/ml lipopolysaccharide, and incubated at 37 degrees C in 5% carbon dioxide. Concentrations of interleukin 1 (IL-1), tumour necrosis factor alpha (TNF alpha), and interleukin 6 (IL-6) were measured at 24 hours, and interferon-gamma and interleukin 2 (IL-2) were measured at 72 hours, with commercially available assays. OUTCOME MEASURES: Production of the monokines IL-1, TNF alpha, and IL-6, and of the lymphokines IL-2 and interferon-gamma, postoperatively. The monokines were expressed as a percentage of the preoperative values/monocyte, and the lymphokines as a percentage of preoperative values/lymphocyte. RESULTS: Production of IL-1 and TNF alpha, but not IL-6, decreased immediately after operation then returned to preoperative values. Production of IL-2 and interferon-gamma were significantly reduced immediately after operation, and that of interferon-gamma was still depressed on the ninth postoperative day. CONCLUSION: Cytokine production is altered after abdominal operations. The production of interferon-gamma may be a more sensitive indicator of altered immune response and vulnerability to infections and tumour growth than concentrations of other cytokines

Association of terminal deoxynucleotidyl transferase with Ku

Terminal deoxynucleotidyl transferase (TdT) catalyzes the addition of nucleotides at the junctions of rearranging Ig and T cell receptor gene segments, thereby generating antigen receptor diversity. Ku is a heterodimeric protein composed of 70- and 86-kDa subunits that binds DNA ends and is required for V(D)J recombination and DNA double-strand break (DSB) repair. We provide evidence for a direct interaction between TdT and Ku proteins. Studies with a baculovirus expression system show that TdT can interact specifically with each of the Ku subunits and with the heterodimer. The interaction between Ku and TdT is also observed in pre-T cells with endogenously expressed proteins. The protein–protein interaction is DNA independent and occurs at physiological salt concentrations. Deletion mutagenesis experiments reveal that the N-terminal region of TdT (131 amino acids) is essential for interaction with the Ku heterodimer. This region, although not important for TdT polymerization activity, contains a BRCA1 C-terminal domain that has been shown to mediate interactions of proteins involved in DNA repair. The induction of DSBs in Cos-7 cells transfected with a human TdT expression construct resulted in the appearance of discrete nuclear foci in which TdT and Ku colocalize. The physical association of TdT with Ku suggests a possible mechanism by which TdT is recruited to the sites of DSBs such as V(D)J recombination intermediates

Relationships between cell division, expression of growth factors and microcirculation in the thyroids of Tg-A2aR transgenic mice and patients with Graves' disease.

Tissue heterogeneity and nodule formation are hallmarks of thyroid growth. This is accounted for by the clonality theory that acknowledges different individual cellular abilities to respond to trophic stimuli. In order to test the hypothesis that functional and mitotic properties of thyrocytes could be influenced by paracrine interactions with neighbour endothelial cells, studies were conducted in both mouse and human goitre models. In the first part of the study, homogenous goitres in C57 black mice were compared with heterogeneous goitres in transgenic hyperthyroid mice expressing the A2 adenosine receptor (Tg-A2aR). The second part of the study concentrated on comparing human thyroid tIssue of control individuals and of patients with Graves' disease. The rate of cell division was evaluated by immunohistochemical detection of cells positive for proliferating cell nuclear antigen (PCNA). Their spatial distribution was then correlated with immunohistochemical cellular expression of growth- and vasoactive-related factors (fibroblast growth factor-2, transforming growth factor-beta, endothelin-1, vascular endothelial growth factor, nitric oxide synthase III), and with microcirculation expansion. Observations were made on digitalised images of histological serial sections. The nearest-neighbour method was used to distinguish between random or clustered distribution. PCNA-positive cells were both randomly and uniformly distributed in homogenous goitres from C57 black mice, and were clustered in tIssue areas identified as papillary and hyperplastic zones in heterogeneous goitres from Tg-A2aR mice. However, they were absent in the so-called compact cellular zones featuring resting cells. Moreover, whereas papillary and hyperplastic zones were highly vascularised, compact zones were nearly free of microvessels. Spatial distribution of dividing cells was positively correlated with the expression of growth-related factors. A similar pattern was observed in the thyroids of patients with Graves' disease. In accordance with the recent demonstration of the presence of angiofollicular units in the thyroid, these data strongly support the hypothesis that functional and mitotic properties of each single thyrocyte, likely to be responsible for growth heterogeneity of hyperplastic glands, may be adjusted at tIssue level by specific interactions with neighbour endothelial cells that, in turn, could alter the mitotic rate of thyrocytes through paracrine signals.Comparative StudyJournal Articleinfo:eu-repo/semantics/publishe

Another Approach To Leaf Shape Comparisons

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/149690/1/tax03918.pd