Streptococcus pyogenes and Lactobacillus rhamnosus differentially induce maturation and production of Th1-type cytokines and chemokines in human monocyte-derived dendritic cells

Dendritic cells (DCs) are the most efficient antigen-presenting cells and thus, have a major role in regulating host immune responses. In the present study, we have analyzed the ability of Gram-positive, pathogenic Streptococcus pyogenes and nonpathogenic Lactobacillus rhamnosus to induce the maturation of human monocyte-derived DCs. Stimulation of DCs with S. pyogenes resulted in strong expression of DC costimulatory molecules CD80, CD83, and CD86 accompanied with a T helper cell type 1 (Th1) cytokine and chemokine response. S. pyogenes also induced interleukin (IL)-2 and IL-12 production at mRNA and protein levels. In addition, IL-23 and IL-27 subunits p40, p19, p28, and EBI3 were induced at mRNA level. In contrast, L. rhamnosus-stimulated DCs showed only moderate expression of costimulatory molecules and produced low levels of cytokines and chemokines. Furthermore, no production of IL-2 or IL-12 family cytokines was detected. Bacteria-induced DC maturation and especially cytokine and chemokine production were reduced when bacteria were heat-inactivated. Our results show that human monocyte-derived DCs respond differently to different Gram-positive bacteria. Although pathogenic S. pyogenes induced a strong Th1-type response, stimulation with nonpathogenic L. rhamnosus resulted in development of semi-mature DCs characterized by moderate expression of costimulatory molecules and low cytokine production.     

Modulation of murine Peyer''s patch immunoglobulin A response by enterotoxigenic Escherichia coli.

Enterotoxigenic Escherichia coli (ETEC) may have profound effects on the capacity of gut-associated lymphoid tissue to mount a secretory immune response because of the potential ability of heat-stable toxin or heat-labile toxin to modulate the immune response. To examine the effects of ETEC or its purified enterotoxins upon the humoral immune response of murine small intestinal Peyer's patch lymphocytes, BDF1 (lipopolysaccharide-responder) and C3H/HeJ (lipopolysaccharide-nonresponder) mice were orally primed with sheep erythrocytes (SRBC) four times during a 2-week period to initiate differentiation of Peyer's patch B lymphocytes to cells committed to anti-SRBC immunoglobulin A (IgA) production. Halfway through the oral priming regimen the mice were gastrically intubated with 10(8) ETEC, 10(8) non-ETEC, or saline. ETEC persisted in the small intestine for at least 7 days at a level of 10(3) to 10(4) bacteria per mouse. Seven days after the last oral dosing with SRBC, Peyer's patch lymphocytes were removed from infected or saline-treated mice and incubated in vitro with SRBC. The ETEC infection had a small effect on the anti-SRBC IgM plaque-forming cell response of SRBC-primed mice but inhibited significantly the anti-SRBC IgA plaque-forming cell response in both BDF1 and C3H/HeJ mice as compared with uninfected controls. The non-ETEC, an isolate from normal mouse small intestine, had no significant effect on either IgM or IgA anti-SRBC plaque-forming cell response. Purified heat-labile toxin, not heat-stable toxin, alone in a dose-dependent manner significantly inhibited both the IgA and IgM plaque-forming cell response of Peyer's patch lymphocytes from primed mice. These data suggest that ETEC can inhibit the development of the gut-associated lymphoid tissue IgA immune response through the immunopharmacological effect of an enterotoxin, the heat-labile toxin.     

Effect of Dietary Essential Amino Acid Limitations upon the Susceptibility to Salmonella typhimurium and the Effect Upon Humoral and Cellular Immune Responses in Mice

We investigated the effects of dietary essential amino acid limitations on the susceptibility of mice to Salmonella typhimurium infections and on humoral and cellular immune (cell-mediated immune) responses of mice. Mice fed synthetic diets limited (significantly less than optimum concentration) in a single essential amino acid (leucine, isoleucine, valine, or lysine) for 3 weeks after they were weaned exhibited significantly enhanced susceptibility to S. typhimurium infection, as evidenced by the higher levels of mortality and spread of the bacterial cells in their livers and spleens compared with mice fed the control diet. Compared with mice fed the control diet, mice fed the diet limited in leucine had a lower ability to clear S. typhimurium cells from the peritoneal cavity 5 min after intraperitoneal injection, whereas mice fed the diet limited in lysine had a greater ability. The in vivo phagocytosis and in vitro bactericidal kinetics against S. typhimurium cells by peritoneal macrophages were not significantly different in the control group and the groups of mice fed experimental diets. Certain experimental groups exhibited significantly lower resistance and antibody response against S. typhimurium SL3770 on day 5 after immunization with heat-killed S. typhimurium SL3770. On day 8 after immunization, the levels of serum antibody against S. typhimurium in the mice fed the experimental diets were comparable to the levels in mice fed the control diet. However, the levels of serum transferrin and complement C3 were significantly lower in mice fed certain experimental diets. The cellular immune capacities of mice fed any of the experimental diets were not impaired compared with the capacities of mice fed the control diet, as measured by spleen cell responsiveness to phytohemagglutinin and the ability to clear infecting Listeria monocytogenes cells from livers and spleens.     

Peptides derived from IgE heavy chain constant region induce profound IgE isotype-specific tolerance

(BALB/c × SJL)F1 mice, perinatally injected with peptide-N-glyconase F-treated, deglycosylated IgE heavy chain or recombinant IgE heavy chain (CH?2-CH?4), were profoundly inhibited in antigen-specific IgE production. There exist minimally two tolerogenic IgE peptides, residing in the CH?2 and CH?4 domains. Peptide I, generated by V8 protease, comprises 39 amino acids within CH?2, beginning at amino acid 103. Peptide E begins at amino acid 312 of the CH?4 domain and extends through the CH?4 domain. The total lack of antigen-specific IgE responses in IgE peptide-treated mice was not due to overproduction of interferon-γ, nor lack of interleukin (IL)-4, as predicted by the Th2/IL-4 paradigm for IgE production. IgE-tolerant mice exhibited comparable levels of circulating anti-IgE antibodies to those of PBS-treated control mice. IgG obtained from sera of both sources failed to inhibit IgE responses in vitro. Moreover, IgE responses of spleen cells from IgE peptides-treated mice were restored by CD4⁺ T cells from PBS-treated control mice. We hypothesize that regulation of antigen-specific IgE responses is mediated by CD4⁺ T cells which normally recognize IgE peptides on IgE precursor B cells, and can be rendered tolerant by perinatal IgE peptide treatment.     

Smokeless tobacco and nicotine bring about excessive cytokine responses of murine memory T-cells

To determine the influence of smokeless tobacco (ST) and nicotine on the cytokine phenotype of memory T-cells, splenic mononuclear cells (SPM) were exposed to 1:10(2) or 1:10(3) dilutions of ST extract (ST-SPM), 10 or 100 microg/ml nicotine (NIC-SPM), or medium (CON-SPM) during 4 days of stimulation with anti-CD3. SPM were then washed extensively to remove residual ST or nicotine and restimulated with anti-CD3 and anti-CD28 in the absence of ST or nicotine. Expression of IL-2, IL-4, IL-10 and IFN-gamma protein and mRNA levels after 4 days of primary stimulation and after 24 and 48 h of restimulation was evaluated using ELISA and RT-PCR, respectively. After 4 days of primary stimulation, SPM exposed to 100 microg/ml nicotine sustained expression of IL-2, IFN-gamma, IL-10 and IL-4 mRNA as opposed to CON-SPM. Restimulation of CON-SPM resulted in maximum re-expression of cytokine mRNA at 24 h and a decline by 48 h. Restimulated NIC-SPM in the absence of nicotine delayed maximal re-expression of IL-2, IFN-gamma, IL-10 and IL-4 mRNA until 48 h. Heightened expression of cytokine mRNA at 48 h was paralleled by a small but significant increase in production of IFN-gamma, IL-4 and IL-10 protein by NIC-SPM as measured by ELISA. In contrast, ST-SPM did not exhibit residual expression of cytokine mRNA after 4 days of primary stimulation. Like NIC-SPM, however, restimulated ST-SPM exhibited maximum IL-2, IL-4, IFN-gamma, and IL-10 mRNA at 48 h. Heightened re-expression of cytokine mRNA at 48 h by ST-SPM was paralleled by increased production of IL-2, IFN-gamma, IL-4 and IL-10 protein. These results indicate that exposure of T-cells to nicotine, but not ST, during a primary immune response result in inordinate cytokine expression after 4 days. In addition, memory T-cells initially exposed to nicotine or ST during a primary immune response, exhibit excessive cytokine expression when T-cells are restimulated in the absence of nicotine or ST. pharmacology.     

Long-lasting heterologous antibody responses after sequential vaccination with A/Indonesia/5/2005 and A/Vietnam/1203/2004 pre-pandemic influenza A(H5N1) virus vaccines

BackgroundAvian influenza A(H5N1) viruses have caused sporadic infections in humans and thus they pose a significant global health threat. Among symptomatic patients the case fatality rate has been ca. 50%. H5N1 viruses exist in multiple clades and subclades and several candidate vaccines have been developed to prevent A(H5N1) infection as a principal measure for preventing the disease.MethodsSerum antibodies against various influenza A(H5N1) clade viruses were measured in adults by ELISA-based microneutralization and haemagglutination inhibition tests before and after vaccination with two different A(H5N1) vaccines in 2009 and 2011.ResultsTwo doses of AS03-adjuvanted A/Indonesia/5/2005 vaccine induced good homologous but poor heterologous neutralizing antibody responses against different clade viruses. However, non-adjuvanted A/Vietnam/1203/2004 booster vaccination in 2011 induced very strong and long-lasting homologous and heterologous antibody responses while homologous response remained weak in naïve subjects.ConclusionsSequential vaccination with two different A(H5N1) pre-pandemic vaccines induced long-lasting high level cross-clade immunity against influenza A(H5N1) strains, thus supporting a prime-boost vaccination strategy in pandemic preparedness plans.     

Difficulties in changing the diet in relation to dietary fat intake among patients with coronary heart disease

OBJECTIVE: To study barriers in following nutritional advice among coronary heart disease patients in relation to dietary fat intake. DESIGN: A cross-sectional study using 4-day food records and a questionnaire with regard to barriers to or difficulties in following dietary advice. SUBJECTS: Altogether, 362 male subjects with coronary heart disease from two separate patient populations (91 + 271) were included in the study, with the mean age of 50 years and 60 years, respectively. The patients were classified into low (< or = 30 E%) or high (> 30 E%) fat intake groups. The patients with low dietary fat intake obtained on an average 10 E% less energy from fat as compared to the high dietary fat intake group. RESULTS: Overall, most patients with coronary heart disease reported difficulties in following nutritional advice when eating in social situations. Patients with high dietary fat intake reported more frequently than patients with low fat intake that they eat like other people without thinking about what they eat. On the other hand, there were no differences between the high and low fat intake groups in the barriers: eating at work, food price, shopping, taste or knowledge of nutrition. CONCLUSIONS: Our results suggest that the sensitivity to social influence is an important factor explaining noncompliance with dietary advice among patients with high dietary fat intake.     

Assessment of the Fundamental Flexural Guided Wave in Cortical Bone by an Ultrasonic Axial-Transmission Array Transducer

The fundamental flexural guided wave (FFGW), as modeled, for example, by the A0 Lamb mode, is a clinically useful indicator of cortical bone thickness. In the work described in this article, we tested so-called multiridge-based analysis, based on the crazy climber algorithm and short-time Fourier transform, for assessment of the FFGW component recorded by a clinical array transducer featuring a limited number of elements. Methods included numerical finite-element simulations and experiments in bone phantoms and human radius specimens (n = 41). The proposed approach enabled extraction of the FFGW component and determination of its group velocity. This group velocity was in good agreement with theoretical predictions and possessed reasonable sensitivity to cortical width (r² = 0.51, p < 0.001) in the in vitro experiments. It is expected that the proposed approach enables related clinical application. Further work is still needed to analyze in more detail the challenges related to the impact of the overlying soft tissue.