Inhibition of sCD23 and immunoglobulin E release from human B cells by a metalloproteinase inhibitor, GI 129471.

Soluble CD23 (sCD23) has been proposed to play an important role in the up-regulation of immunoglobulin E (IgE) synthesis. Production of sCD23 is dependent on the proteolytic cleavage of membrane CD23, but the protease(s) involved in this process remain unknown. Preliminary data, obtained by testing a panel of protease inhibitors, suggested that this enzyme may be a zinc-dependent metalloproteinase. Therefore, we investigated the effect of a standard hydroxamate-type Zn2+ metalloproteinase inhibitor (GI 129471) on both sCD23 and IgE release from human tonsillar B cells, stimulated with interleukin-4 (IL-4) and anti-CD40. Incubation of cells for 3 days with GI 129471 inhibited the production of sCD23 with an IC50 of 602 nm+/-3 nm (n=3), but by 14 days the activity of the compound against sCD23 had decreased by greater than threefold (IC50 2+/-0.26 microM; n=3). On the other hand, GI 129471 caused a potent inhibition of IgE production, with no apparent loss of activity over the culture period (14 days: IC50 250 nm+/-72 nm; n=3). Time-course studies showed that, despite loss of activity against sCD23, inhibition of sCD23 production early in the culture was able to cause a potent and long-lasting inhibitory effect on IgE. Furthermore, we also showed that the activity of GI 129471 is selective for IgE, as no effect was seen on immunoglobulin G1 (IgG1) or IgG4 production at test concentrations as high as 10 microM. These results support the hypothesis that metalloproteinases may be involved in the proteolytic cleavage of CD23 and subsequent regulation of IgE synthesis. Inhibition of the protease(s) responsible for such cleavage may be of value in the treatment of allergic disease.

Heligmosomoides polygyrus immunomodulatory factor (IMF), targets T-lymphocytes.

Experiments were performed to investigate the immunological site of action of an immunomodulatory factor (IMF), isolated from the gastrointestinal nematode Heligmosomoides polygyrus. IMF inhibited antibody production in murine and human 'T-helper (Th-2) driven' immunoassays. The effects were mediated via T lymphocytes as T cell-depleted cultures failed to respond to IMF, a result confirmed by prepulsing discrete cell subsets with the immunomodulant. Although the molecular nature and mode of action of IMF has yet to be determined, it would appear to be a relatively small non-proteinaceous molecule. From this data, we suggest that H. polygyrus secretes a systemically-active IMF from the intestinal lumen, to down-regulate Th-2 cell development in order to promote its survival in a potentially immunologically hostile environment.

Using mental imagery with subclinical OCD to 'freeze' contamination in its place: evidence for looming vulnerability theory.

The present research examines the possibility that 'freezing' or slowing-down the rate at which threats can advance and thereby blocking a sense of looming vulnerability can reduce fears of contamination and avoidance behavior among individuals with obsessional symptoms. Mental imagery was used to reduce the rate at which threat can advance by means of instructions to imagine that contamination was 'frozen' in place and unable to move. Measures included self-reports of anxiety and worry, and indirect assessments of fear and avoidance behavior. A parallel mental imagery condition was used to examine the possibility that accentuating the spread or contamination, or its 'looming', would in turn accentuate fear and avoidance. The results, particularly of the more unobtrusive measures, indicated that freeze imagery reduced fear and avoidance for the relatively obsessional participants. In addition, support was found that it reduced fear for participants with relatively higher levels of imagination. However, the freeze imagery paradoxically seemed to sensitize the non-obsessional participants to possibilities of contamination they had not previously considered, and thus increased their fear. The results provide support for the looming vulnerability model of anxiety and suggest applications to treatment.

Peripheral blood based T cell-containing and T cell-depleted culture systems for human IgE synthesis: the role of T cells.

BACKGROUND: Comparable T cell-containing and T cell-depleted culture systems for human IgE synthesis are currently not available. OBJECTIVE: This has prompted us to develop peripheral blood mononuclear cell (PBMC) based culture systems for human IgE synthesis in the presence and absence of T cells. METHODS: In this paper we describe simplified conditions for in vitro synthesis of high levels of IgE by human peripheral blood B cells, both in T cell-containing cultures and in anti-CD40 stimulated T cell-depleted cultures. RESULTS: T cell-depleted cultures released approximately 20 times more IgE [range 410-2220 ng/mliter (mean 1270 ng/mliter); based on six experiments using cells from three donors] than did T cell-containing cultures [range 23-105 ng/mliter (mean 58 ng/mliter); based on 15 experiments using cells from three donors]. Reconstitution experiments were performed to investigate the role of T cells on IgE synthesis. Adding T cells back to the anti-CD40 stimulated T cell-depleted cultures resulted in a dose-dependent inhibition of IgE production. In the absence of anti-CD40 low numbers of T cells stimulated, while high numbers suppressed, IgE production: the optimal ratio of T cells to non-T cells for maximal IgE production was found to be 1:1. At this ratio, irradiated (non-replicating) T cells supported a much greater IgE synthesis than did non-irradiated T cells. CONCLUSION: The development of these systems provides directly comparable T cell-containing and T cell-depleted cultures for human IgE synthesis from peripheral blood, allowing further study of the role of T cells in IgE regulation. These systems will also be of use for determining whether potential modulators of IgE synthesis act on the T cells or on other cell types.

Potentiation of in vitro synthesis of human IgE by cyclosporin A (CsA).

In this study, we investigated the modulatory effects of CsA on in vitro synthesis of IgE, IgG1 and IgG4 by human peripheral blood mononuclear cells (PBMC). In contrast to its known immunosuppressive effect, we have demonstrated that a low dose of CsA (10(-7) M, 120 ng/ml) potentiated IgE production by up to 40-fold (i.e. from 33 +/- 4.5 to 1346 +/- 290 ng/ml). This potentiation was specific for IgE since no such effect was demonstrable with IgG1 and IgG4. Potentiation of IgE synthesis by CsA in the PBMC cultures was partly due to CsA acting on T cells, as demonstrated by the addition of CsA-treated T cells to T cell-depleted cultures. However, potentiation was also demonstrable in a T cell-depleted, anti-CD40-stimulated culture (four-fold increase from 400 +/- 48 to 1606 +/- 127 ng/ml). Our data therefore suggest that there are at least two mechanisms for CsA-induced potentiation of IgE synthesis, one T cell-dependent and the other T cell-independent. The clinical implications of these findings are discussed with regard to the use of CsA in the treatment of Th2-mediated diseases.

Using statistical process control to make data-based clinical decisions.

Applied behavior analysis is based on an investigation of variability due to interrelationships among antecedents, behavior, and consequences. This permits testable hypotheses about the causes of behavior as well as for the course of treatment to be evaluated empirically. Such information provides corrective feedback for making data-based clinical decisions. This paper considers how a different approach to the analysis of variability based on the writings of Walter Shewart and W. Edwards Deming in the area of industrial quality control helps to achieve similar objectives. Statistical process control (SPC) was developed to implement a process of continual product improvement while achieving compliance with production standards and other requirements for promoting customer satisfaction. SPC involves the use of simple statistical tools, such as histograms and control charts, as well as problem-solving techniques, such as flow charts, cause-and-effect diagrams, and Pareto charts, to implement Deming's management philosophy. These data-analytic procedures can be incorporated into a human service organization to help to achieve its stated objectives in a manner that leads to continuous improvement in the functioning of the clients who are its customers. Examples are provided to illustrate how SPC procedures can be used to analyze behavioral data. Issues related to the application of these tools for making data-based clinical decisions and for creating an organizational climate that promotes their routine use in applied settings are also considered.

Age-specific trends in mortality from ischemic heart disease and cerebrovascular disease in Australia.

Analysis of ischemic heart disease (IHD) and cerebrovascular disease mortality rates in Australia shows that: first, deaths from IHD increased from 1950 to the mid-1960s with successive cohorts experiencing higher mortality rates. Around 1967 this trend stopped simultaneously in men over 35 years and women over 45 years and mortality rates from IHD began to decline at similar rates throughout the population. Second, deaths from cerebrovascular disease have declined in both sexes and all age groups over 35 years throughout the period 1950-1978. This change has been more pronounced for women than men. Third, the relative frequency of IHD and cerebrovascular disease as the cause of death has changed in women. IHD has become the more frequent cause of death in the older age groups. More recently this change in relative frequency has occurred in younger women as well.

Laminar airflow protection in bone marrow transplantation.

A laminar airflow room was used to provide a low-pathogen environment for a child with lymphopenic immune deficiency transplanted with paternal bone marrow. Comparison of flora from the patient, personnel, and the environment indicated that no colonization with exogenous organisms occurred in the patient during the 45-day period of study. The number of organisms recovered from the laminar airflow room was exceedingly small. Conventional hospital isolation rooms contained more bacteria and fungi than the laminar airflow room, even when strict aseptic procedures were followed in the former. Patients with lymphopenic immune deficiency and agranulocytosis admitted to conventional isolation rooms were colonized with exogenous organisms within 1 week. Each developed infection with these strains, and one patient died. Laminar airflow isolation seems at present the best means to prevent exogenous infection during hospitalization of patients with lymphopenic and other severe immune-deficiency diseases and may be essential when bone marrow transplantation is performed to treat their immunological defect.