Distinctive homing profile of pathogen-specific activated lymphocytes in human urinary tract infection.

In contrast to other mucosal sites, information on migration/homing of lymphocytes activated in the human urinary tract is lacking. The expression of lymphocyte homing receptors (HR) on pathogen-specific antibody-secreting cells (ASC) originating from the urinary tract (patients with pyelonephritis, PN) was compared to that on antigen-specific ASC originating from the intestine (patients with gastroenteritis) or from a parenteral site (tetanus toxoid-immunized volunteers). In the PN group, 61% of ASC expressed the gut HR, alpha(4)beta(7,) 52% the peripheral lymph node HR, L-selectin, and 13% the skin HR, CLA. This homing profile of urinary tract-originating lymphocytes was found to differ from both of the two major vaccination routes, intestinal (less gut-targeting) or parenteral (more gut-targeting, less targeting to parenteral sites). This information on targeting of the immune response may prove useful when developing vaccines against urinary tract infection (UTI).

Local immune response to upper urinary tract infections in children.

Vaccines are needed against urinary tract infections (UTIs) in children, as episodes of pyelonephritis (PN) may cause renal scarring. Local immune mechanisms are regarded to confer protection, yet they have been poorly characterized for children. This study explores the local immune response in children by looking for newly activated pathogen-specific antibody-secreting cells (ASC), expected to appear transiently in the circulation as a response to UTI. Urinary tract-originating ASC specific to each patient's own pathogen or P fimbria were studied in 37 children with PN. The children were examined for recidivism and renal scarring in a 6-month follow-up study. Pathogen-specific ASC were found in 33/37 children, with the magnitude increasing with age. In contrast to the case for adults, with immunoglobulin A (IgA) dominance, in 18/33 cases IgM dominated the response, and this occurred more frequently in infants (63%) than in older children (30%). The most vigorous response was found to whole Escherichia coli bacteria (geometric mean, 63 +/- 2,135 ASC/10(6) peripheral blood mononuclear cells [PBMC]), yet responses were found to P fimbriae (13 +/- 33 ASC/10(6) PBMC), too. The response peaked at 1 to 2 weeks and was low/negligible 3 to 7 weeks after the beginning of symptoms. Recidivism was seen in seven patients, and renal scarring was seen in nine patients. In conclusion, a response of circulating ASC was found in children with UTIs, with the magnitude increasing with age. Since IgM is not present in urine, the IgM dominance of the response suggests that systemic immune mechanisms are more important in the immune defense in children than in adults. In 81% of patients, no recidivism was seen, suggesting a successful immune defense.

Specific probiotics in enhancing maturation of IgA responses in formula-fed infants.

The first months of life represent a critical period for the maturation of the infant's immune system and, thus, a window of opportunity for measures to reduce the risk of disease. We hypothesized that specific probiotics might promote mucosal immunologic maturation in formula-fed infants. The numbers of cow's milk-specific and total IgA-secreting cells were measured at 3, 7, and 12 mo of age in a double-blind placebo-controlled study of 72 infants with early artificial feeding. The infants consumed infant formula supplemented with specific probiotics (Lactobacillus GG and Bifidobacterium lactis Bb-12) or placebo during the first year of life. Further analyses of the serum concentrations of the IgA-inducing cytokine TGF-beta2 and the soluble innate microbial receptor sCD14 were conducted. The numbers of cow's milk-specific IgA secreting cells were significantly higher in infants receiving probiotics compared with those receiving placebo (p = 0.045, ANOVA for repeated measures). At 12 mo of age, the serum concentrations of sCD14 were 1479 pg/mL [95% confidence interval (CI) 1373-1592] in infants receiving probiotics and 1291 pg/mL (95% CI 1152-1445) in infants receiving placebo (p = 0.046). Administration of the probiotics Lactobacillus GG and Bifidobacterium lactis Bb-12 at the time of introduction of cow's milk in the infant's diet results in cow's milk-specific IgA antibody responsiveness that may be the result of increased production of sCD14.

Effect of probiotics and breastfeeding on the bifidobacterium and lactobacillus/enterococcus microbiota and humoral immune responses.

OBJECTIVE: To assess impact of probiotics and breastfeeding on gut microecology. STUDY DESIGN: Mothers were randomized to receive placebo or Lactobacillus rhamnosus GG before delivery, with treatment of the infants after delivery. We assessed gut microbiota, humoral immune responses, and measured soluble cluster of differentiation 14 (sCD14) in colostrum in 96 infants. RESULTS: Fecal Bifidobacterium and Lactobacillus/Enterococcus counts were higher in breastfed than formula-fed infants at 6 months; P <.0001 and P=.01, respectively. At 3 months, total number of immunoglobulin (Ig)G-secreting cells in breastfed infants supplemented with probiotics exceeded those in breastfed infants receiving placebo; P=.05, and their number correlated with concentration of sCD14 in colostrum. Total numbers of IgM-, IgA-, and IgG-secreting cells at 12 months were higher in infants breastfed exclusively for at least for 3 months and supplemented with probiotics as compared with breastfed infants receiving placebo; P=.005, P=.03 and P=.04, respectively. Again, sCD14 in colostrum correlated with numbers of IgM and IgA cells; P=.05 in both. CONCLUSIONS: We found an interaction between probiotics and breastfeeding on number of Ig-secreting cells, suggesting that probiotics during breastfeeding may positively influence gut immunity.

No evidence of cross-reactivity of human antibodies to a 33-mer peptide of the alpha-gliadin component of gluten with Bordetella pertussis pertactin.

A 33-mer peptide of the alpha-gliadin component of gluten was recently identified as primary initiator of the inflammatory response to gluten in coeliac disease (CD) patients. This proline-glutamine-rich peptide (PG-peptide) is highly homologous to internal sequence of pertactin, an immunogenic protein of Bordetella pertussis. Using enzyme immunoassays, we measured serum antibodies to pertactin and to PG-peptide in 167 Finnish subjects including pertussis vaccine recipients and pertussis patients, CD and non-CD patients and healthy individuals. We found no cross-reactivity between human antibodies to the two different components, suggesting that neither pertussis immunization nor disease contributes to the pathogenesis of CD.

Unique characteristics of the intestinal immune system as an inductive site after antigen reencounter.

BACKGROUND: Immunization prepares the body for a reencounter with the microbe. Information on the targeting of immune effector cells during secondary immune response--that is, lymphocyte homing--is scarce. In the present study, the homing potentials of lymphocytes are examined after antigen reencounter at mucosal versus nonmucosal sites. METHODS: Orally or parenterally immunized volunteers were reimmunized orally or parenterally with Salmonella typhi Ty21a, and the expression of the gut homing receptor (HR), alpha(4)beta(7), and of the peripheral lymph node HR, L-selectin, was investigated in circulating antigen-specific antibody-secreting cells (ASCs). Lymphocytes were sorted by HR expression and examined for antibody production, by use of an enzyme-linked immunospot assay. RESULTS: After oral reimmunization, 90% of ASCs were alpha(4)beta(7) positive and 88% were L-selectin positive, an expression profile that differed significantly from that found after oral primary immunization. After parenteral reimmunization, 45% of ASCs were alpha(4)beta(7) positive and 79% were L-selectin positive, similar to the results after parenteral primary immunization. The route of priming had no effect on HR patterns in either case. CONCLUSIONS: Homing potentials of lymphocytes depend on the site of antigen reencounter. Whereas the HR profile after parenteral reimmunization resembles that after primary immunization, the profile after oral reimmunization is uniquely characterized by high expression of both HRs, suggesting gut-localized memory and effective homing ability to both the mucosal and systemic immune system. These data may prove valuable in the search for the most effective immunization route in humans.

P fimbria-specific B cell responses in patients with urinary tract infection.

Local immune response may be important in defense against urinary tract infection (UTI). P fimbria, an important virulence factor of Escherichia coli, is a noteworthy candidate for use in a vaccine against pyelonephritis (PN). Eleven patients with PN and 14 patients with lower urinary tract infection (LUTI) caused by E. coli were studied for mucosa-derived antibody-secreting cells (ASCs) and for urinary antibodies. In the 10 patients with P-fimbriated (P+) E. coli, an ASC response to P fimbria was found in 5 of 5 patients who had PN and 1 of 5 patients who had LUTI. The response to P fimbria was stronger among patients with P+ PN than among patients with PN caused by non-P-fimbriated E. coli (P-) (P<.001) or patients with P+ LUTI (P<.001). The response to P fimbria was also stronger than the response to outer-membrane protein A among all patients with PN. P fimbria-specific urinary immunoglobulin A antibody levels were higher among patients with P+ PN than those with P- PN. The results show a P fimbria-specific local immune response, which further encourages the use of P fimbria in locally administrable UTI vaccines.

PFGE and pertactin gene sequencing suggest limited genetic variability within the Finnish Bordetella parapertussis population.

The outer-membrane protein pertactin (Prn) of Bordetella pertussis, Bordetella parapertussis and Bordetella bronchiseptica is believed to function as an adhesin and is an important immunogen. The emergence of B. pertussis and B. bronchiseptica Prn variants has been reported. The aim of this study was to determine whether similar variation is found in B. parapertussis Prn and to characterize Finnish clinical B. parapertussis isolates that were collected in 1982-2000. Of 76 B. parapertussis isolates studied, seven (9 %) were found to have silent and non-silent nucleotide changes. In addition, one (1 %) had eight PQP repeats instead of nine. Three closely related B. parapertussis XbaI PFGE patterns were found. Genetic variation of B. parapertussis was found to be very limited, suggesting that B. parapertussis is a stable organism that is well-adapted to its own ecological niche.

Probiotics and prevention of atopic disease: 4-year follow-up of a randomised placebo-controlled trial.

Perinatal administration of the probiotic Lactobacillus rhamnosus strain GG (ATCC 53103), reduces incidence of atopic eczema in at-risk children during the first 2 years of life (infancy). We have therefore assessed persistence of the potential to prevent atopic eczema at 4 years. Atopic disease was diagnosed on the basis of a questionnaire and a clinical examination. 14 of 53 children receiving lactobacillus had developed atopic eczema, compared with 25 of 54 receiving placebo (relative risk 0.57, 95% CI 0.33-0.97). Skin prick test reactivity was the same in both groups: ten of 50 children previously given lactobacillus compared with nine of 50 given placebo tested positive. Our results suggest that the preventive effect of lactobacillus GG on atopic eczema extends beyond infancy.

Evaluation of a new cellulose sponge-tipped swab for microbiological sampling: a laboratory and clinical investigation.

A new type of swab (Cellswab; Cellomeda, Turku, Finland), utilizing a highly absorbent cellulose viscose sponge material, was compared to some traditional swabs. The survival of 14 aerobic and 10 anaerobic and microaerophilic bacterial species in the Cellswab, two commercial swab transport systems (Copan, Brescia, Italy, and Orion Diagnostica, Espoo, Finland), and one Dacron swab (Technical Service Consultants Ltd. [TSC], Heywood, United Kingdom) was evaluated. Bacteria were suspended in broth, into which the swabs were dipped. The Cellswab absorbed 1.3 times more fluid and released 3.5 times more fluid upon plating than the other swabs. Aerobic bacteria were stored in dry tubes, the others in transport medium, at 4 degrees C and room temperature (RT), for up to 14 days. Swab samples were transferred to plates at 0, 1, 2, 4, 7, and 14 days. For 10 strains the Cellswab yielded > or =10% of the original CFU for longer than all the other swabs. In the clinical study, the ability of the Cellswab to detect beta-hemolytic streptococci from throat samples (n = 995) was compared to that of the TSC Dacron swab. The swabs performed equally, both when their samples were transferred to plates immediately and after storage for 1 day at 4 degrees C or RT. The changes in normal microbiota after storage were also similar. The Cellswab was found to perform at least as well as ordinary swabs. It was better at storing fastidious strains, and at keeping bacteria viable for long storage times; it might well be a useful replacement or complement to ordinary swabs.

Bordetella pertussis protein pertactin induces type-specific antibodies: one possible explanation for the emergence of antigenic variants?

Divergence has been found between Bordetella pertussis vaccine strains and circulating strains. Polymorphism in pertactin (Prn) is essentially limited to region 1, which is made up of repeats. Today, the 3 most prevalent Prn variants are Prn1-3. Vaccine strains produce Prn1, whereas Prn2 is the predominant type found in circulating strains. We investigated how variation in region 1 affects the production of human serum antibodies. Individuals infected by Prn2 strains had significantly fewer antibodies to Prn1 did than those infected by Prn3 strains and those immunized with a booster dose of acellular vaccines containing Prn1. Moreover, in contrast to vaccine recipients and subjects infected by Prn3 strains, individuals infected by Prn2 strains had hardly any antibodies specific to the variable region of Prn1. These results indicate that conformational changes have occurred in the variable region of Prn, which may offer a possible explanation for the emergence of Prn2 strains in certain countries.

Infantile pertussis rediscovered in China.

Immunization against pertussis was introduced in China in the 1960s. Since the 1970s, no culture-confirmed pertussis cases have been reported in the country. We report six infants with culture-confirmed pertussis, who were initially diagnosed as having other respiratory diseases at Beijing Children's Hospital, Beijing.

Rapid typing of Bordetella pertussis pertussis toxin gene variants by LightCycler real-time PCR and fluorescence resonance energy transfer hybridization probe melting curve analysis.

A LightCycler real-time PCR hybridization probe assay was developed for rapid typing of gene variants of the Bordetella pertussis virulence factor pertussis toxin. The assay correctly identified the ptxS1 alleles of all strains tested, comprising 57 Finnish clinical isolates and 2 vaccine strains. The method is simple, reliable, and suitable for large-scale screening of B. pertussis strains.

HLA-B27-transfected (Salmonella permissive) and HLA-A2-transfected (Salmonella nonpermissive) human monocytic U937 cells differ in their production of cytokines.

The cytokine secretion of the Salmonella-permissive, HLA-B27-positive U937 cells was examined, as it was previously shown that these cells kill Salmonella less efficiently than controls. Salmonella-permissive U937 cells showed upregulated production of interleukin 10 and to a lesser extent tumor necrosis factor alpha. HLA-B27-associated modulation of cytokine responses may have importance in the pathogenesis of reactive arthritis.

Elimination of Salmonella enterica serotype enteritidis in intestinal epithelial cells by mechanisms other than nitric oxide.

Production of nitric oxide (NO) by intestinal epithelial cells is induced after infection with Salmonella spp. or some other enteroinvasive bacteria. However, direct evidence of the role of NO in the elimination of intracellular pathogens in intestinal mucosa has not been established. This study investigated whether NO mediates killing of Salmonella enterica serovar Enteritidis in human intestinal epithelial cells by using parent Henle-407 cell line and a transfected cell line not capable of induced NO production (Henle-NO(def)). NO synthesis was studied as combined accumulation of nitrite and nitrate, as inducible nitric oxide synthase (iNOS) protein determined by Western blotting and as iNOS mRNA detected by reverse transcription (RT)-PCR. Although parent and Henle-NO(def) cells differed markedly in their ability to produce NO after infection, they eliminated S. Enteritidis equally, as determined by cfu counts. The presence of aminoguanidine, a selective iNOS inhibitor, during the infection blocked the production of NO but did not affect the elimination of the bacteria. These data suggest that NO does not have a direct role in the elimination of intracellular Salmonellae by human intestinal epithelial cells.