Cellular and humoral immune responses and protection against schistosomes induced by a radiation-attenuated vaccine in chimpanzees

The radiation-attenuated Schistosoma mansoni vaccine is highly effective in rodents and primates but has never been tested in humans, primarily for safety reasons. To strengthen its status as a paradigm for a human recombinant antigen vaccine, we have undertaken a small-scale vaccination and challenge experiment in chimpanzees (Pan troglodytes). Immunological, clinical, and parasitological parameters were measured in three animals after multiple vaccinations, together with three controls, during the acute and chronic stages of challenge infection up to chemotherapeutic cure. Vaccination induced a strong in vitro proliferative response and early gamma interferon production, but type 2 cytokines were dominant by the time of challenge. The controls showed little response to challenge infection before the acute stage of the disease, initiated by egg deposition. In contrast, the responses of vaccinated animals were muted throughout the challenge period. Vaccination also induced parasite-specific immunoglobulin M (IgM) and IgG, which reached high levels at the time of challenge, while in control animals levels did not rise markedly before egg deposition. The protective effects of vaccination were manifested as an amelioration of acute disease and overall morbidity, revealed by differences in gamma-glutamyl transferase level, leukocytosis, eosinophilia, and hematocrit. Moreover, vaccinated chimpanzees had a 46% lower level of circulating cathodic antigen and a 38% reduction in fecal egg output, compared to controls, during the chronic phase of infection

State diagrams of the heart – a new approach to describing cardiac mechanics

<p>Abstract</p> <p>Background</p> <p>Cardiac time intervals have been described as a measure of cardiac performance, where prolongation, shortening and delay of the different time intervals have been evaluated as markers of cardiac dysfunction. A relatively recently developed method with improved ability to measure cardiac events is Tissue Doppler Imaging (TDI), allowing accurate measurement of myocardial movements.</p> <p>Methods</p> <p>We propose the state diagram of the heart as a new visualization tool for cardiac time intervals, presenting comparative, normalized data of systolic and diastolic performance, providing a more complete overview of cardiac function. This study aimed to test the feasibility of the state diagram method by presenting examples demonstrating its potential use in the clinical setting and by performing a clinical study, which included a comparison of the state diagram method with established echocardiography methods (E/E' ratio, LVEF and WMSI). The population in the clinical study consisted of seven patients with non ST-elevation myocardial infarction (NSTEMI) and seven control subjects, individually matched according to age and gender. The state diagram of the heart was generated from TDI curves from seven positions in the myocardium, visualizing the inter- and intraventricular function of the heart by displaying the cardiac phases.</p> <p>Results</p> <p>The clinical examples demonstrated that the state diagram allows for an intuitive visualization of pathological patterns as ischemia and dyssynchrony. Further, significant differences in percentage duration between the control group and the NSTEMI group were found in eight of the totally twenty phases (10 phases for each ventricle), e.g. in the transition phases (Pre-Ejection and Post-Ejection). These phases were significantly longer (> 2.18%) for the NSTEMI group than for the control group (p < 0.05). No significant differences between the groups were found for the established echocardiography methods.</p> <p>Conclusion</p> <p>The test results clearly indicate that the state diagram has potential to be an efficient tool for visualization of cardiac dysfunction and for detection of NSTEMI.</p

The distinct role of CD4+ and CD8+ T-cells during the anti-tumour effects of targeted superantigens

To target T-cells to the tumour area we created a recombinant protein of the bacterial superantigen (SAg) Staphylococcal enterotoxin A (SEA) and the Fab-fragment of a tumour-reactive antibody. This antibody-targeted SAg immunotherapy therapy has been shown to be highly efficient, eliminating > 95% of the pulmonary metastasis in mice carrying established melanoma micrometastases. Earlier studies demonstrated that elimination of the C215-expressing B16-melanoma lung metastasis was dependent on interferon (IFN)-γ release and expression of perforin. In the present study, therapeutic effector functions were analysed both locally at the tumour site and systemically in the spleen. In order to elucidate the role of each T-cell subset during Fab–SEA therapy, CD4 knock-out (KO) and CD8 KO mice were used. Tumour size reduction was statistically significant in Fab–SEA-based tumour therapy in both types of T-cell-deficient mice compared to wild-type mice. CD4 KO mice displayed a drastic reduction in the number of tumour-infiltrating macrophages and CD8+ T-cells. Therapy-induced accumulation of perforin-containing cells at the tumour site was significantly impaired in CD8 KO mice, and marginally in CD4 KO mice. Moreover, CD4 KO mice failed to produce substantial amounts of the tumour suppressive cytokine IFN-γ. This is in sharp contrast to normal mice where a massive local release was recorded. CD8 KO mice displayed a spontaneous production of interleukin (IL)-4 and IL-10 locally in the tumour. Neither normal nor CD4 KO mice produced detectable levels of these Th-2-associated cytokines. The high level of IL-10 was demonstrated to inhibit Fab–SEA tumour therapy, since the therapeutic efficacy was significantly higher in IL-10 KO mice. These results illustrate the importance of a finely tuned cellular collaboration to regulate the various phases of an efficient anti-tumour immune response. © 1999 Cancer Research Campaig

Enhanced Monocyte Response and Decreased Central Memory T Cells in Children with Invasive Staphylococcus aureus Infections

Staphylococcus aureus has emerged as a significant pathogen causing severe invasive disease in otherwise healthy people. Despite considerable advances in understanding the epidemiology, resistance mechanisms, and virulence factors produced by the bacteria, there is limited knowledge of the in vivo host immune response to acute, invasive S. aureus infections. Herein, we report that peripheral blood mononuclear cells from patients with severe S. aureus infections demonstrate a distinctive and robust gene expression profile which is validated in a distinct group of patients and on a different microarray platform. Application of a systems-wide modular analysis framework reveals significant over-expression of innate immunity genes and under-expression of genes related to adaptive immunity. Simultaneous flow cytometry analyses demonstrated marked alterations in immune cell numbers, with decreased central memory CD4 and CD8 T cells and increased numbers of monocytes. CD14+ monocyte numbers significantly correlated with the gene expression levels of genes related to the innate immune response. These results demonstrate the value of applying a systems biology approach that reveals the significant alterations in the components of circulating blood lymphocytes and monocytes in invasive S. aureus infections

Babassu aqueous extract (BAE) as an adjuvant for T helper (Th)1-dependent immune responses in mice of a Th2 immune response-prone strain

<p>Abstract</p> <p>Background</p> <p>The aqueous extract of a Brazilian palm-tree fruit - the babassu - (BAE) exerts a clear immunostimulative activity <it>in vivo</it>. In the present work, the possibility that BAE can promote Th1 immune responses in mice of a Th2 immune response-prone strain - the BALB/c was investigated. BAE itself, and preparations consisting of <it>Leishmania amazonensis </it>promastigote extract (LE), adsorbed or not to Al(OH)₃, and in the presence or not of BAE, were used as immunogens. LE and Al(OH)₃have been shown to preferentially elicit Th2 immune responses.</p> <p>Results</p> <p>The addition of BAE to LE-containing immunogenic preparations, adsorbed or not to Al(OH)₃, clearly promoted the <it>in vitro </it>production of interferon γ (IFN-γ), a major Th1-dependent cytokine, and not of interleukin (IL-)4 (a Th2-dependent cytokine), by LE-stimulated splenocytes of immunized BALB/c mice. It also promoted the <it>in vivo </it>formation of IgG2a anti-LE antibodies. However, immunization with LE by itself led to an increased production of IL-4 by LE-stimulated splenocytes, and this production, albeit not enhanced, was not reduced by the addition of BAE to the immunogen. On the other hand, the IL-4 production by LE-stimulated splenocytes was significantly lower in mice immunized with a preparation containing Al(OH)₃-adsorbed LE and BAE than in mice immunized with the control preparation of Al(OH)₃-adsorbed LE without BAE. Moreover, an increased production of IFN-γ, and not of IL-4, was observed in the culture supernatants of splenocytes, from BAE-immunized mice, which were <it>in vitro </it>stimulated with BAE or which received no specific <it>in vitro </it>stimulus. No differences in IL-10 (an immunoregulatory cytokine) levels in the supernatants of splenocytes from mice that were injected with BAE, in relation to splenocytes from control mice, were observed. The spontaneous <it>ex vivo </it>production of NO by splenocytes of mice that had been injected with BAE was significantly higher than the production of NO by splenocytes of control mice.</p> <p>Conclusions</p> <p>Based on the results described above, BAE, or biologically active molecules purified from it, should be further investigated as a possible adjuvant, in association or not with aluminium compounds, for the preferential induction of Th1-dependent immune responses against different antigens in distinct murine strains and animal species.</p

Superantigen reactive Vβ6+ T cells induce perforin/granzyme B mediated caspase-independent apoptosis in tumour cells

The endogenous viral superantigen 7 in DBA/2 mice serves as a target antigen on syngeneic ESb-MP lymphoma cells for allogeneic graft-vs-leukaemia reactive cells. Allogeneic viral superantigen 7 reactive Vβ6+ T cells are able to transfer graft-vs-leukaemia reactivity and to kill specifically viral superantigen 7+ ESb-MP tumour cells in vitro. Here we elucidate the mechanism of this superantigen specific cell lysis. Already 10 min after co-incubation with in vitro stimulated Vβ6+ T cells, viral superantigen 7+ ESb-MP tumour cells show an apoptotic phenotype (Annexin V-positivity, DNA-fragmentation). This extremely rapid type of cell death is not mediated by the death inducing ligands CD95L, TRAIL and TNF but by perforin and granzyme B. Surprisingly, neither mitochondria nor any of the known caspases appear to be involved in this type of tumour cell killing. In contrast, nitric oxide, released by activated macrophages and endothelial cells, induces in the same tumour cells another type of apoptosis which is much slower and involves mitochondria and caspase activation. A synergistic effect between the two different effector mechanisms of superantigen reactive donor cytotoxic T lymphocytes and nitric oxide releasing host macrophages and endothelial cells might explain the effective immune rejection of even advanced metastasised cancer in this graft-vs-leukaemia animal model

Diastolic time – frequency relation in the stress echo lab: filling timing and flow at different heart rates

A cutaneous force-frequency relation recording system based on first heart sound amplitude vibrations has been recently validated. Second heart sound can be simultaneously recorded in order to quantify both systole and diastole duration