Induction of Apoptosis Reduces Immunogenicity of Human T-Cell Lines in Mice

Apoptotic cells, e.g. postinflammatory neutrophils, were reported to be engulfed by phagocytes without induction of an inflammatory response. We investigated the humoral immune response of BALB/c mice after repeated injection of viable or apoptotic human T cells. Following interleukin-2 (IL-2) deprivation, phytohaemagglutinin (PHA)/IL-2 expanded human T-cell lines were irradiated with UV-B light to induce apoptosis, confirmed by propidium iodide staining of Triton X-100-lysed cells. Indirect immunofluorescence was used to detect antilymphocyte antibodies 7 days after each injection. We found high levels of antilymphocyte antibodies in all animals immunized with viable T cells, whereas animals injected with apoptotic cells showed a significantly reduced humoral immune response. We conclude that apoptotic cells induce poor xenoreactive T-cell responses when compared with viable cells.     

Prevalence of Artemisia species pollinosis in western Poland: impact of climate change on aerobiological trends, 1995-2004.

BACKGROUND: Artemisia species pollen represents a major cause of allergy in Central Europe. Variations in the pollen season, the influence of climate variables and the prevalence of pollinosis to it were analyzed in Poznan, in western Poland between 1995 and 2004. METHODS: A Hirst volumetric spore trap was used for atmospheric sampling. Pollination date trend analysis and Spearman correlation tests were performed. Skin prick tests (SPT) and allergen specific immunoglobulin (lg)E antibody measurements were performed in 676 and 524 patients, respectively. RESULTS: The Artemisia species pollen season grew longer due to a clear advance in the starting day and only a slightly earlier end point; the peak day also came slightly earlier. Rainfall in the first fortnight of July highly influenced pollen season severity. Temperature was directly correlated with daily Artemisia species pollen levels; relative humidity was inversely correlated. Twelve percent of patients had a positive SPT reaction to Artemisia species. Their symptoms were rhinitis and conjunctivitis (15%), atopic dermatitis (15%), chronic urticaria (14.3%), bronchial asthma (2.4%), and facial and disseminated dermatitis (1.3%). Elevated specific IgE concentrations were detected in the sera of 10.1% of patients. CONCLUSIONS: Artemisia species pollen is an important cause of pollinosis in western Poland. Pollen season intensity is highly influenced by rainfall in the previous weeks. Trends towards earlier season starts and longer duration, possibly caused by climate change, may have an impact on the allergic population.     

Disease-related changes in work absenteeism of adolescents from 1967 to 1987

The negative development of sickness figures up to 1976/77 as well as the subsequent change of this trend in adolescents are analysed with regard to specific diagnoses. Both, the positive trend change and remaining problems are presented.     

B lymphocytes secreting IgG linked to latent transforming growth factor- beta prevent primary cytolytic T lymphocyte responses

B lymphocytes secreting IgG linked to latent transforming growth factor (TGF)-beta (IgG-TGF-beta) prevent cytolytic T lymphocyte (CTL) responses to unrelated antigens in mixed lymphocyte cultures (MLC) so long as resting resident macrophages and functional Fc receptors are present. This was shown using IgG-secreting plaque-forming cells (PFC) to sheep erythrocytes (SRBC) obtained from popliteal lymph nodes of mice injected repeatedly in foot pads with SRBC. Remarkably, as few as approximately 300 PFC prevented CTL responses of 5 x 10(5) normal syngeneic spleen cells in MLC. Supranatants of short-term cultures of PFC also prevented CTL responses, and suppression was prevented by eliminating or dissociating IgG and TGF-beta present in supranatants or by antibody against active TGF-beta. Furthermore, the latency- associated peptide of latent TGF-beta was detected in approximately 10% of foci of IgG captured from single PFC, indicating that at least some B lymphocytes secrete IgG-TGF-beta as a complex. Resting resident macrophages (which do not produce latent TGF-beta) and functional Fc receptors were required for suppression, consistent with idea that IgG- TGF-beta is taken up through Fc receptors for IgG and that active TGF- beta, cleaved from latent TGF-beta of the complex, is delivered directly to potentially responding CTL. If CTL responses in man are similarly regulated by B lymphocytes, then an ongoing B cell response in patients with chronic viral infections or bearing immunogenic cancers may prevent effective therapeutic vaccination.      

Decrease in the number of lower affinity (type II) nerve growth factor receptors on embryonic sensory neurons does not affect fiber outgrowth

Nerve growth factor binds to two different specific receptors on responsive cells. The relationship of these two receptors is not fully understood at this time. We have studied the binding of labeled NGF to a different strain of white leghorn chicken embryo dorsal root ganglionic cells. The equilibrium dissociation constants for the two sites (K = 4.1 ± 1.8 × 10^?11M, K = 1.0 ± 0.8 × 10^?9M) are identical to those obtained previously. Also, the number of type I sites per cell (3.8 ± 1.3 × 10³) is the same as that previously determined. However, the number of type II sites per cell (1.9 ± 1.3 × 10⁴) is significantly different than that previously determined. This 2.5-fold decrease in the number of type II sites does not affect the concentration of NGF needed to obtain maximal fiber outgrowth from explanted sensory ganglia. The rate of association (1.2 ± 0.2 × 10⁷ M^?1 sec^?1 at 22°C) of labeled NGF with receptors on sensory neurons from this different strain of chickens is identical to that previously obtained. The rate of association of NGF with its receptors on sensory neurons was also determined at 4°C. This rate constant (2.1 ± 1.1 × 10⁶ M^?1 sec^?1) along with the rate constants obtained at 22° and 37°C were used to determine an activation energy for the binding of NGF to its receptors. The activation energy obtained (16.2 kcal/mole) suggests that binding is not a diffusion-controlled process.     

The effect of hydroxychloroquine on platelet activation in model experiments

Journal of Thrombosis and Thrombolysis - Hydroxychloroquine (HCQ) is an antimalarial agent with pleiotropic effects and now represents a cornerstone in the management of patients with autoimmune...