Stress,coping, family conflict,and adolescent alcohol use

This study examined alcohol use among seventh graders in relation to life events, daily hassles, the supportive quality of the family environment, coping, and anxiety. Four hundred twenty-five students participated, 228 girls and 197 boys. Stepwise regression and discriminant function analyses indicated that the students reported more alcohol use if they also reported more life events, more daily hassles, and more conflict in the family. A stress-buffering effect of low family conflict on life events could not be substantiated for extent of alcohol use. The results are discussed in the context of the developmental transitions of adolescence.     

Role of interleukin 1 in antigen-induced exacerbations of murine arthritis.

The mechanism underlying the chronic and intermittent course of rheumatoid arthritis is not elucidated. In the present study, the role of interleukin 1 (IL-1) was investigated in exacerbations of antigen-induced arthritis in mice. A flare-up of smoldering inflammation (weeks 3 to 4 of antigen-induced arthritis) was inducible by injection of a small amount of methylated bovine serum albumin into the hypersensitive knee joint. Immunohistochemistry showed IL-1 expression in the synovial lining layer and in focal areas of the inflamed synovium during the flare-up. IL-1 was also measured in 1-hour culture supernatant of synovial tissue taken during the flare-up by a bioassay. The expression of both immunoreactive and bioactive IL-1 in the hypersensitive joint peaked around 6 hours after antigen (2 micrograms of methylated bovine serum albumin) injection and declined thereafter. Antigen rechallenge induced an acute joint swelling of the arthritic joint but not in the naive joint of the sensitized mouse, yet synovia of both joints produced IL-1 after antigen injection. Remarkably, a single intravenous injection of rabbit anti-IL-1 alpha and -beta antibodies 1 hour before antigen rechallenge neutralized IL-1 in the joint. Anti-IL-1 treatment significantly reduced the antigen-induced joint swelling (30 to 40%) but did not affect the profound influx of polymorphonuclear cells in the onset of the exacerbation. However, a profound relief of the inflammation (synovitis) was obtained by IL-1 blockade on day 4 of the exacerbation. Chondrocyte proteoglycan synthesis was markedly suppressed in the antigen-challenged naive knee joints suggesting that this was a direct IL-1 effect as the inflammation was insignificant. Anti-IL-1 treatment was able to maintain chondrocyte proteoglycan synthesis in the antigen-rechallenged joint, which was highly suppressed in the control group. Furthermore, the enhanced proteoglycan breakdown in the antigen-rechallenged joints was significantly decreased in the anti-IL-1 group. We concluded that IL-1 is an important mediator in exacerbations of murine arthritis, and amelioration of cartilage pathology was obtained with anti-IL-1 antibody treatment.     

Cationic immune complex arthritis in mice--a new model. Synergistic effect of complement and interleukin-1.

A novel cationic immune-complex-mediated arthritis (ICA) model was developed in mice. The highly cationic protein lysozyme was coupled to poly-L-lysine (PLL) and injected intra-articularly into the knee joint of the mouse, shortly after systemic administration of specific antibodies. A vehement joint inflammation developed, characterized by severe joint swelling and the influx of predominantly polymorphonuclear (PMN) leukocyte. Unique properties were combined in this protein. First, an excellent retention of the antigen in joint structures was found, facilitating sufficient IC formation in the synovial tissue and at the cartilage surface. Secondly, PLL.lysozyme appeared to be a potent inducer of interleukin-1 (IL-1). Similar IL-1 production was measured at 6 hours, in both immune or nonimmune mice. Neutralization with antibodies against either IL-1 alpha or IL-1 beta revealed that IL-1 alpha was the dominant cytokine. Resident cells were responsible for this IL-1 production since a comparable IL-1 signal was measured after intra-articular injection of PLL.lys in neutropenic mice. We further investigated whether IL-1 and complement factors were involved in the onset of this ICA. Neutralizing the IL-1 production with antibodies directed against IL-1 alpha and beta showed a significant decrease in joint swelling. Complement depletion by cobra venom factor also prevented the onset of arthritis for the greater part. Only a minor swelling remained at 6 hours after eliciting arthritis, which was similar to the swelling after injecting the antigen alone and probably reflects IL-1 mediated inflammation. In this study, the authors show a synergistic action of IL-1 and complement in the onset of cationic ICA. Unique properties of the antigen such as excellent retention and its ability to induce IL-1 are combined within one molecule and make this antigen arthritogenic in the presence of antibodies and complement activation.     

Host susceptibility to the attaching and effacing bacterial pathogen Citrobacter rodentium

Many studies have shown that genetic susceptibility plays a key role in determining whether bacterial pathogens successfully infect and cause disease in potential hosts. Surprisingly, whether host genetics influence the pathogenesis of attaching and effacing (A/E) bacteria such as enteropathogenic and enterohemorrhagic Escherichia coli has not been examined. To address this issue, we infected various mouse strains with Citrobacter rodentium, a member of the A/E pathogen family. Of the strains tested, the lipopolysaccharide (LPS) nonresponder C3H/HeJ mouse strain experienced more rapid and extensive bacterial colonization than did other strains. Moreover, the high bacterial load in these mice was associated with accelerated crypt hyperplasia, mucosal ulceration, and bleeding, together with very high mortality rates. Interestingly, the basis for the increased susceptibility was not due to LPS hyporesponsiveness, as the genetically related but LPS-responsive C3H/HeOuJ and C3H/HeN mouse strains were also susceptible to infection. Analysis of the intestinal pathology in these susceptible strains revealed significant crypt epithelial cell apoptosis (terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end label staining) as well as bacterial translocation to the mesenteric lymph nodes. Further studies with infection of SCID (T- and B-lymphocyte-deficient) C3H/HeJ mice demonstrated that loss of lymphocytes had no effect on bacterial numbers but did reduce crypt cell apoptosis and delayed mortality. These studies thus identify the adaptive immune system, crypt cell apoptosis, and bacterial translocation but not LPS responsiveness as contributing to the tissue pathology and mortality seen during C. rodentium infection of highly susceptible mouse strains. Determining the basis for these strains' susceptibility to intestinal colonization by an A/E pathogen will be the focus of future studies.     

Rapid development of severe hyperplastic gastritis with gastric epithelial dedifferentiation in Helicobacter felis-infected IL-10(-/-) mice.

Interleukin (IL)-10 is a potent anti-inflammatory and immune-regulatory cytokine. Mice deficient in IL-10 production (IL-10(-/-)) develop a spontaneous inflammatory bowel disease, indicating that IL-10 is an important regulator of the mucosal immune response in vivo. To study the role of IL-10 in the host response to gastric Helicobacter infection, stomachs of IL-10(-/-) and wild-type mice were colonized with Helicobacter felis, as a model of human H. pylori infection. Within 4 weeks of H. felis infection, wild-type mice develop a mild, focal chronic gastritis. In contrast, H. felis-infected IL-10(-/-) mice develop a severe hyperplastic gastritis, characterized by a dense, predominantly mononuclear cell inflammation of the mucosa and submucosa and epithelial cell proliferation and dedifferentiation. Within 4 weeks of H. felis infection, there are striking alterations in the character of the gastric epithelium from IL-10(-/-) mice, including a profound loss of parietal and chief cells, focal de novo production of acidic mucins, and marked epithelial proliferation with disordered epithelial architecture. These findings indicate that, in the absence of IL-10, the inflammatory and immunological responses of the murine host to gastric colonization with Helicobacter is a rapidly evolving pathological process with features that mimic those associated with H. pylori infection in humans. H. felis-infected IL-10(-/-) mice may provide a model with which to investigate the cellular and molecular changes that stem from gastric infection with H. pylori.     

Epitope specificity and isoforms of the mycobacterial 19-kilodalton antigen.

The topography and specificity of B- and T-cell stimulatory epitopes from the 19-kDa protein of Mycobacterium tuberculosis were investigated by using overlapping synthetic peptides. Murine antisera identified two cryptic epitopes (residues 11 to 30 and 61 to 80) and one species-specific immunodominant epitope (residues 140 to 159). Immunoglobulins G1 and G2a antibody isotypes varied for the respective peptide immunogens but without relationship to the T-cell cytokine profiles which were characterized by high gamma interferon and low interleukin 5 levels. Antisera to recombinant M. tuberculosis 19-kDa protein (rGST-19) cross-reacted with homologous proteins of similar size from organisms of the Mycobacterium avium-intracellulare complex. Two-dimensional gel electrophoresis revealed differences in the number, relative mobility, and charge of isoforms of the 19-kDa protein, possibly reflecting posttranslational modifications. The immunodominant T-cell epitope from the M. tuberculosis 19-kDa protein (residues 61 to 80) and the corresponding peptide sequence from Mycobacterium avium subsp. intracellulare (residues 64 to 83), differing at five residues, were both recognized in a genetically permissive manner. Peptides 61-80 and 64-83 stimulated cross-reactive responses in BALB/c (H-2d) mice, while in the C57BL/10 (H-2b) strain, responses to peptide 61-80 were species specific. In purified protein derivative-positive healthy individuals, the M. avium subsp. intracellulare peptide stimulated stronger responses than did the M. tuberculosis peptide, whereas patients with active tuberculosis had enhanced in vitro T-cell responses to both peptides.     

Immunization with glycosylated Kb-binding peptides generates carbohydrate-specific,unrestricted cytotoxic T cells

Cytotoxic T cells (CTL) recognize target proteins as short peptides presented by major histocompatibility complex (MHC) class I restriction elements. However, there is also evidence for peptide-independent T cell receptor (TCR) recognition of target proteins and non-protein structures. How such T cell responses are generated is presently unclear. We generated carbohydrate (CHO)-specific, MHC-unrestricted CTL responses by coupling di- and trisaccharides to K^b- or D^b-binding peptides for direct immunization in mice. Four peptides and three CHO have been analyzed with the CHO either in terminal or central positions on the carrier peptide. With two of these glycopeptides, with galabiose (Galα1-4Gal; Gal₂) bound to a homocysteine (via an ethylene spacer arm) in position 4 or 6 in a vesicular stomatitis virus nucleoprotein-derived peptide (RGYVYQGL binding to K^b), CTL were generated which preferentially killed target cells treated with glycopeptide compared to those treated with the core peptide. Polyclonal CTL were also found to kill target cells expressing the same Gal₂ epitope in a glycolipid. By fractionation of CTL, preliminary data indicate that glycopeptide-specific K^b-restricted CTL and unrestricted CHO-specific CTL belong to different T cell populations with regard to TCR expression. The results demonstrate that hapten-specific unrestricted CTL responses can be generated with MHC class I-binding carrier peptides. Different models that might explain the generation of such responses are discussed.     

Adoptive transfer of T lymphocytes to T-cell-depleted mice inhibits Escherichia coli translocation from the gastrointestinal tract.

Bacterial translocation is defined as the passage of viable bacteria from the gastrointestinal (GI) tract to extraintestinal sites, such as the mesenteric lymph node (MLN), spleen, liver, kidneys, and blood. Previously, we reported that depletion of CD4+ and/or CD8+ T cells promotes bacterial translocation from the GI tract to the MLN. In the present study, CD4+ and/or CD8+ T cells, harvested from donor mice, were adoptively transferred to mice previously depleted of T cells by thymectomy plus intraperitoneal injection of rat anti-mouse T-cell monoclonal antibodies. The adoptively transferred CD4+ and/or CD8+ T cells inhibited the translocation of Escherichia coli from the GI tract. Migration of the adoptively transferred T cells to the spleens and MLNs of the recipient mice was determined by utilizing Thy 1.1+ donor cells adoptively transferred into mice whose cells express the Thy 1.2 marker. These results provide further evidence of the importance of T cells in the host immune defense against bacterial translocation from the GI tract.     

Clinical significance of immunopathological findings in patients with post-pericardiotomy syndrome. II. The significance of serum inhibition and rosette inhibitory factors.

Serum inhibition factors (SIF) that suppress phytohaemagglutinin-induced blast transformation of normal lymphocytes, and lymphocyte E-rosette inhibitory factors (RIF) that inhibit the T cell-specific property of E-rosette formation were determined in sixty-five patients before and after cardiac surgery. SIF was found in the first post-operative week in almost all patients; patients with complete post-pericardiotomy syndrome (PPS) still had these factors in the fourth postoperative week. The appearance of SIF correlated well with the intensity of the PPS. Persistence of SIF in eleven out of eighteen patients with clinically incomplete PPS reaffirms the probability that they had an 'immunologically' positive PPS. RIF was to be found in one third of the patients with complete or incomplete PPS and may be of prognostic value. The two factors were not identical.