Bruton's tyrosine kinase is required for TLR-induced IL-10 production.

Bruton's tyrosine kinase (Btk) is a critical signaling mediator downstream of the B cell Ag receptor. X-linked agammaglobulinemia is caused by mutations in Btk resulting in multiple defects in B cell development and function, and recurrent bacterial infections. Recent evidence has also supported a role for Btk in TLR signaling. We demonstrate that Btk is activated by TLR4 in primary macrophages and is required for normal TLR-induced IL-10 production in multiple macrophage populations. Btk-deficient bone marrow-derived macrophages secrete decreased levels of IL-10 in response to multiple TLR ligands, compared with wild-type (WT) cells. Similarly, Btk-deficient peritoneal and splenic macrophages secrete decreased IL-10 levels compared with WT cultures. This phenotype correlates with Btk-dependent induction of NF-kappaB and AP-1 DNA binding activity, and altered commensal bacteria populations. Decreased IL-10 production may be responsible for increased IL-6 because blocking IL-10 in WT cultures increased IL-6 production, and supplementation of IL-10 to Btk-deficient cultures decreased IL-6 production. Similarly, injection of IL-10 in vivo with LPS decreases the elevated IL-6 serum levels during endotoxemia in Btk-deficient mice. These data further support a role for Btk in regulating TLR-induced cytokine production from APCs and provide downstream targets for analysis of Btk function.

Therapeutic approaches targeting intestinal microflora in inflammatory bowel disease.

Inflammatory bowel diseases, ulcerative colitis, and Crohn's disease, are chronic intestinal disorders of unknown etiology in which in genetically susceptible individuals, the mucosal immune system shows an aberrant response towards commensal bacteria. The gastrointestinal tract has developed ingenious mechanisms to coexist with its autologous microflora, but rapidly responds to invading pathogens and then returns to homeostasis with its commensal bacteria after the pathogenic infection is cleared. In case of disruption of this tightly-regulated homeostasis, chronic intestinal inflammation may be induced. Previous studies showed that some commensal bacteria are detrimental while others have either no influence or have a protective action. In addition, each host has a genetically determined response to detrimental and protective bacterial species. These suggest that therapeutic manipulation of imbalance of microflora can influence health and disease. This review focuses on new insights into the role of commensal bacteria in gut health and disease, and presents recent findings in innate and adaptive immune interactions. Therapeutic approaches to modulate balance of intestinal microflora and their potential mechanisms of action are also discussed.

Effects of lactulose on the intestinal microflora of periparturient sows and their piglets.

The periparturient period of animals (and humans) is very stressful and influenced by the microecosystem of the gastrointestinal tract (GIT). Performance and productivity of animal husbandry depend on the health of animal mothers and their offspring. We investigated the influence of prebiotic amounts of lactulose in sows and their piglets. Two experimental trial sows received daily 30 ml lactulose, 71 field trial sows received daily 45 ml lactulose during their periparturient period (10 days before until 10 days after parturison). The weaners of trial sows received 15 ml lactulose per 1 kg baby food 10 days before and 10 days after weaning.The effect of lactulose was recorded by performance parameters like number of piglet born alive, losses until weaning, body mass of piglets, daily weight gain of weaners until 35 days after weaning. The effect of lactulose on GIT microflora was estimated by bacterial counts of faeces of sows (total aerobic bacteria, Gram-negative bacteria, Clostridium (C.) perfringens). In order to show a previously unknown effect of lactulose we investigated the levels of antibodies to phospholipase C (PLC) of C. perfringens in plasma of experimental sows and in colostral and ripe milk of field sows. Lactulose influenced the performance parameters of sows in a non-significant way. In case of weaners we recorded significant daily weight gains. Lactulose significantly influenced total aerobic bacterial counts, C. perfringens counts in faeces of sows 20 days after parturison. Under experimental conditions it was shown that trial sows and their piglets had higher IgG-antibody levels to C. perfringens PLCs than the control animals. Similar results were found under field conditions. Trial sows had significant higher IgG-anti LPS (J5) antibodies in milk 10 days after birth.

The role of bacteria as a local defence mechanism in the ear, nose and throat.

The mucosae of the oro-nasopharynx in man are asymptomatically colonised by a commensal flora. This commensal flora consists largely of non-pathogenic bacteria but potentially pathogenic bacteria, such as S. pneumoniae, H. influenzae, M. catarrhalis can also be part of it. The commensal flora can be affected by host factors such as age or antibiotic usage but will in itself also affect its host. In addition to being a source of resistance genes it will also protect the host against exogenous, non-commensal pathogens. This protective effect is the result of three characteristics of the commensal flora. The commensal flora will hinder the establishment of new pathogens on the mucosa (termed colonisation resistance), it will especifically stimulate the immune system and it will induce formation of protective antibodies.

Los gérmenes anaerobios como responsables de la infección quirúrgica / Anaerobic microorganisms responsible for surgical infection

Objetivo. Establecer la frecuencia de los gérmenes anaerobios en la aparición de la infección quirúrgica. Señalar cuáles son los principales responsables de los mismos. Valorar las posibles particularidades de la infección por anaerobios en nuestro medio. Material y métodos. Se estudian un total de 4.997 especímenes quirúrgicos de 6.599 pacientes intervenidos en nuestro servicio a lo largo de 6 años. Se analizan los gérmenes responsables, se establece la frecuencia de los anaerobios, destacando los más frecuentes, y las particularidades de los mismos. Resultados. Los aislamientos de gérmenes anaerobios constituyeron el 18,6 por ciento del total de los microorganismos aislados por el laboratorio. La mayor parte de los aislamientos se obtuvieron en líquido peritoneal, seguido de muestras de abscesos y herida quirúrgica, y el carácter de los mismos fue polimicrobiano. La patología de índole isquémica, seguida de la inflamatoria, fueron las principales responsables del aislamiento de estos microorganismos. Por familias, fueron los bacilos gramnegativos los más frecuentes, seguidos a distancia por los cocos grampositivos y los bacilos grampositivos, mientras que los cocos gramnegativos presentan escasa incidencia. Los gérmenes más frecuentes fueron Bacteroides fragilis, que junto con otros bacteroides (ovatus, uniformis, tetaiotaomicron) y Prevotella melaninogenica constituyen cerca del 50 por ciento del total de los anaerobios aislados. Conclusiones. Cabe destacar el importante significado clínico que en nuestra experiencia tiene el aislamiento de estos gérmenes (bacteroides y prevotelas), tanto por su relativa alta incidencia como por la elevada tasa de resistencias antimicrobianas de alguno de estos microorganismos (AU)

Alteration of a polyclonal to an oligoclonal immune response to cecal aerobic bacterial antigens in TCR alpha mutant mice with inflammatory bowel disease.

Since lumenal bacteria have been postulated to play an important role in the pathogenesis of inflammatory bowel disease (IBD), we investigated the humoral response to cecal aerobic bacterial antigens by Western blot analysis in TCR alpha -/- mice which spontaneously develop IBD. The sera from TCR alpha -/- mice revealed an alteration of the recognition pattern against aerobic bacterial antigens from polyclonal to oligoclonal with age. This alteration was not observed in TCR delta -/- and TCR alpha +/- mice. The alteration of the recognition pattern in TCR alpha -/- mice was associated with production of autoantibodies against tropomyosin and the development of IBD. The unique population of CD4+ TCR alpha -beta + cells in TCR alpha -/- mice may be involved in the recognition of these bacterial antigens and the absence of the alpha chain may result in the alteration of immune response.

Immune response in patients with intra-abdominal infections treated with carbapenems.

The immune responses against isolated microorganisms in patients with intraabdominal infections treated with meropenem or imipenem/cilastatin were investigated. Fifty-nine patients received meropenem 500 mg t.i.d. intravenously for 3-21 days (mean 5.4 days) and 50 patients imipenem/cilastatin 500 mg/500 mg t.i.d. intravenously for 3-17 days (mean 5.1 days). Three serum samples were taken from each patient, the first sample at admission, the second sample between three and seven days after start of antibiotic treatment, and the third sample between 14 and 28 days later. Ninety-eight per cent of the patients in the meropenem group and 95% of the patients in the imipenem/cilastatin group were cured. There was no difference in the clinical outcome between the two treatment groups. Escherichia coli, Bacteroides fragilis group, anaerobic cocci, Staphylococcus epidermidis, and Klebsiella spp. predominated among the isolated microorganisms. Thirty-nine patients in the meropenem group had significant immune responses against one or more of the isolated microorganisms while 31 patients in the imipenem/group had significant responses. E. coli and B. fragilis gave rise in antibody titres in most patients indicating that these species are the most important pathogens in intraabdominal infections.

Susceptibility to pristane-induced arthritis is altered with changes in bowel flora.

Pristane-induced arthritis (PIA) is unique among the animal arthritides in that a non-infectious, non-antigenic oil induces a chronic immune based arthritis with a prolonged delay between exposure to the inciting agent and development of the disease. Mice with pristane-induced arthritis have elevated T cell and humoral responses to the 65 kDa heat shock protein derived from Mycobacterium bovis (hsp65) and in common with several other models of autoimmune diseases the incidence of PIA is markedly suppressed by preimmunisation with hsp65 in Freund's incomplete adjuvant (Thompson et al. (1990) Eur. J. Immunol. 20, 2479). Recent studies have investigated how autoimmune reactions to heat shock proteins are involved in the development of arthritis. Arthritic CBA/Igb mice given pristane alone develop antibodies to both hsp65 and GroEl (bacterial 60 kDa heat shock proteins) and to hsp58 (the mammalian equivalent). Moreover, the splenic T cells of such mice proliferate vigorously in response to both bacterial and mammalian 60 kDa heat shock proteins. Remarkably, the anti-hsp65 antibody response in normal mice rises rapidly with age, directly correlating with the age related incidence of PIA. In addition, specific pathogen free mice (SPF) maintained in an isolator have negligible anti-hsp65 responses but these convert to positive responses if the animals are exposed to the open part of the animal facility (Thompson et al. (1992) Arthritis Rheum. 35, 139).(ABSTRACT TRUNCATED AT 250 WORDS)

Estudos sobre o controle e disseminaçäo bacteriana em carcaças de frangos de abatedouros industriais / Studies on bacterial control and dissemination on carcasses in a broiler processing plant

Uma série de experimentos foi realizada para verificar a participaçäo da microbiota dos tegumentos cutâneos e do trato digestivo de aves vivas na carga bacteriana residual das carcaças, avaliar a influência das operaçöes de abate e algumas alteraçöes nos níveis de contaminaçäo e disseminaçäo bacteriana de carcaças de frangos. Houve uma progressiva reduçäo no número de bactérias aeróbias totais e enterobactérias nas carcaças durante a sequência das operaçöes de abate, com reduçäo aproximada de dois a três log10, ao final do ciclo. A carga bacteriana total foi maior nas operaçöes de depenaçäo e evisceraçäo. Os níveis de contaminaçäo da água de resfriamento foram maiores no primeiro tanque que no terceiro. Níveis de cloro residual atuam na reduçäo da carga microbiana da água dos tanques de resfriamento. As carcaças de frangos apresentaram maior índice de contaminaçäo por salmonelas após o resfriamento do que antes. Experimentos com Escherichia coli resistente ao ácido nalidíxico ratificaram estes achados e, também, mostraram que a contaminaçäo de origem entérica é mais importante na disseminaçäo de bactérias para as carcaças que a de origem cutânea. A imersäo de aves em água a 45-50§C, 54§C, 65§C e 74§C por 15 segundos antes do escaldamento näo teve efeito significativo na reduçäo da contaminaçäo final de carcaças. A obstruçäo da cloaca de frangos com tampöes introduzidos imediatamente após a sangria e o tratamento das carcaças com ácido fosfórico no estágio final de resfriamento tiveram influência na reduçäo da contaminaçäo das carcaças por bactérias aeróbias totais e enterobactérias

Adequate function of the immune system and physiological microflora are closely correlated.

It is already known that physiological microflora of the digestive system plays an important role in local immunity. Studies on immunomodulating activity of some autoantibodies have shown that drugs affecting intestinal microflora possess potent immunosuppressive effect on systemic immunity. These observations inspired to recent investigation on the mechanisms of the influence of digestive tract bacteria on the immune system.