Conjoint Professor Caroline Blackwell

Cytokine (TNFa, interleukin-6) release of whole blood from healthy donors was challanged with mistletoe extract standardised for mistletoe lectin-1 (sML) and control substances (E. coli endotoxin; phytohaemagglutinin). The rationale of this investigation was non-proven warnings that pro-inflammatory cytokines induce by the application of standardised mistletoe lectins may induce tumor cell proliferation. These investigations provided evidence that non-cytotoxic concentrations of sML did not induced enhanced TNFa or interleukin-6 secretion compared to non-challenged control cells. Cytotoxic concentrations of sML, however, induced significantly higher cytokine levels than the control, obviously due to non-physiological stimuli. Immunomodulation with clinically relevant, low-dose sML incubation did not induce proinflammatory cytokine secretion in vitro.

During February and March 1995, a survey of meningococcal carriage in 625 school children was carried out in a suburb of Athens in which there was a large number of ethnic Greeks who had immigrated from Russia beginning in the early 1990s. The objectives of the study were: (1) to determine if factors associated with carriage of meningococci observed in a previous study of Greek school children were similar for the immigrant population; (2) to compare phenotypic characteristics of meningococci from the immigrant population with those isolated from children in Athens. Overall isolation rate for meningococci was 82/625 (13.1%), significantly higher than that found for school children in Athens (5.8%) during the winter of 1990-1991 (5.8%) (¿2=25.98, P=0.0000003). By univariate analysis, carriage was not associated with sex, number of individuals per household, blood group, secretor status, socioeconomic level or maternal smoking; however, it was associated with fathers' smoking. The high proportion of men who smoked compared with the low proportion of women smokers might contribute to this finding. The main serogroup of meningococci isolated from this population was A (28%). While serogroup A appears to be more prevalent among Russian and Kurdish immigrants (14%) than among Greek school children or military recruits (4%), there has not been an increase in group A meningococcal disease in Greece. The isolation rate for N. lactamica was high 105/625 (17.3%). A few of these strains bound some of the monoclonal antibodies used for meningococcal serotyping and subtyping, and they are being examined in greater detail. Copyright (C) 1999 Federation of European Microbiological Societies.

Exposure to cigarette smoke is a major risk factor for sudden infant death syndrome and also for respiratory infections in children. It has been suggested that toxigenic bacteria colonizing the respiratory tract might play a role in some cases of sudden infant death syndrome and nicotine has been demonstrated to enhance the lethality of bacterial toxins in a model system. Pyrogenic toxins of Staphylococcus aureus have been identified in tissues of infants who died of sudden infant death syndrome. It has been suggested that some of these deaths were due to induction of inflammatory mediators by infectious agents during a period when infants are less able to control these responses. The aim of this study was to assess the effects of a water-soluble cigarette smoke extract on the production of tumor necrosis factor a and nitric oxide from human monocytes in response to staphylococcal toxic shock syndrome toxin 1 or infection of the monocytes with respiratory syncytial virus. Cell culture supernatants were examined by a bioassay using mouse fibroblasts (L-929 cell line) for tumor necrosis factor a activity and by a spectrophotometric method for nitrite. Compared with monocytes incubated with medium only, monocytes incubated with any of the factors or their combinations tested in the study released higher levels of tumor necrosis factor a and lower levels of nitric oxide. Incubation with cigarette smoke extract increased tumor necrosis factor a from respiratory syncytial virus-infected cells while it decreased tumor necrosis factor a from cells incubated with toxic shock syndrome toxin. Incubation with cigarette smoke extract decreased the nitric oxide production from respiratory syncytial virus-infected cells while it increased the nitric oxide production from cells incubated with toxic shock syndrome toxin. Monocytes from a minority of individuals demonstrated extreme tumor necrosis factor a responses and/or very high or very low nitric oxide. The proportion of samples in which extreme responses with a very high tumor necrosis factor a and very low nitric oxide were detected was increased in the presence of the three agents to 20% compared with 0% observed with toxic shock syndrome toxin 1 or 4% observed with cigarette smoke extract or respiratory syncytial virus. Copyright (C) 1999 Federation of European Microbiological Societies.

Epidemiological evidence indicates infants immunised against diphtheria, pertussis and tetanus (DPT) are at decreased risk of sudden infant death syndrome (SIDS). Asymptomatic whooping cough and pyrogenic toxins of Staphylococcus aureus have been implicated in the aetiology of SIDS. The objectives of the present study were: (1) to determine if the DPT vaccine induced antibodies cross-reactive with the staphylococcal toxins; (2) to determine if antibodies to the pertussis toxin (PT) and the staphylococcal toxins were present in the sera of women during late pregnancy; (3) to examine the effects of infant immunisation on levels of antibodies to PT and the staphylococcal toxins; (4) to assess the effects of changes in immunisation schedules in the UK on the incidence and age distribution of SIDS. Enzyme-linked immunosorbent assays (ELISA) were used to measure binding of rabbit or human IgG to the DPT vaccine, PT, toxic shock syndrome toxin-1 (TSST-1) and staphylococcal enterotoxins A (SEA), B (SEB) and C (SEC). Neutralisation activity of anti-DPT serum was assessed by a bioassay for induction of nitric oxide from human monocytes by the staphylococcal toxins. Anti-DPT serum bound to the DPT vaccine, PT and each of the staphylococcal toxins. It also reduced the ability of the four toxins to induce nitric oxide from monocytes. In pregnant women, levels of IgG to PT, SEC and TSST-1 decreased significantly in relation to increasing weeks of gestation while antibodies to SEA and SEB increased. In infants' sera there were significant correlations between levels of IgG bound to DPT and IgG bound to PT, TSST-1 and SEC but not SEA or SEB. Antibody levels to the toxins in infants declined with age; sera from infants =2 months of age had higher levels of IgG bound to the toxins than those older than 2 months. This pattern was observed for infants whose immunisation schedules began at 2 months of age or 3 months of age. The decrease in IgG bound to the toxins was, however, less for those immunised at 2 months. The decrease in SIDS deaths after the change in immunisation schedules was greatest in the 4-6-month age range. While DPT immunisation might prevent some unexplained infant deaths due to asymptomatic whooping cough, these data indicate that immunisation with DPT also induces antibodies cross-reactive with pyrogenic staphylococcal toxins implicated in many cases of SIDS. Passive immunisation of infants who have low levels of these antibodies might reduce further the numbers of these infant deaths. Copyright (C) 1999 Federation of European Microbiological Societies.

Carriage of non-serogroupable Neisseria meningitidis or Neisseria lactamica induces antibodies protective against meningococcal disease. Antibodies directed against outer membrane proteins are bactericidal and the serotype and subtype outer membrane protein antigens are being examined for their value as vaccine candidates for serogroup B disease. The aim of this study was to examine the effect of carriage of these two Neisseria species among children and young adults on induction of antibodies to outer membrane components from strains causing disease in Greece. Among 53 patients with meningococcal disease, IgG or IgM antibodies were detected by ELISA in 9 of 13 (69%) from whom the bacteria were isolated and 27 of 40 (67%) who were culture-negative. For military recruits (n=604), the proportion of carriers of meningococci with IgM or IgG to outer membrane proteins was higher than non-carriers, P<0.05 and P=0.000000, respectively. Among school children (n=319), the proportion with IgM or IgG to outer membrane proteins for carriers of meningococci was higher compared with non-carriers, P=0.000000 and P=0000043, respectively. Carriage of N. lactamica was not associated with the presence of either IgM or IgG to the outer membrane proteins in the children. The higher proportion of children (50%) with IgM to outer membrane proteins compared with recruits (10%) might reflect more recent exposure and primary immune responses to the bacteria. The lack of association between antibodies to outer membrane proteins and carriage of N. lactamica could reflect observations that the majority of N. lactamica isolates from Greece and other countries do not react with monoclonal typing reagents. Bactericidal antibodies to meningococci associated with high levels of IgG to N. lactamica were found in a previous study; these are thought to be directed to antigens other than outer membrane proteins or capsules and imply antigens such as lipo-oligosaccharide are involved in induction of antibodies cross-reactive with meningococci. Copyright (C) 1999 Federation of European Microbiological Societies.

It has been suggested that pyrogenic toxins of Staphylococcus aureus are involved in the series of events leading to some cases of sudden infant death syndrome (SIDS). The objectives of the study were to screen tissues from SIDS infants for pyrogenic toxins and to compare incidence of identification of these toxins among these infants from different countries. An enzyme-linked immunosorbent assay (ELISA) and a flow cytometry method were used to screen body fluids and frozen or formalin-fixed tissues for pyrogenic toxins of S. aureus, toxic shock syndrome toxin 1 (TSST), staphylococcal enterotoxins A (SEA), B (SEB), and C1 (SEC). Toxins were identified in tissues of 33/62 (53%) SIDS infants from three different countries: Scotland (10/19, 56%); France (7/13, 55%); Australia (16/30, 53%). In the Australian series, toxins were identified in only 3/19 (16%) non-SIDS deaths (¿2=5.42, P<0.02). The flow cytometry method was useful for toxin detection in both frozen and fixed tissues, but ELISA was suitable only for frozen tissues or those fixed for less than 12 months. Identification of pyrogenic toxins in >50% of SIDS infants from three different countries indicated further investigation into the role the toxins play in cot deaths might result in development of additional measures to reduce further the incidence of these infant deaths. Copyright (C) 1999 Federation of European Microbiological Societies.

The number of cases of meningococcal disease reported to the Meningitis Reference Laboratory in Athens rose dramatically in 1996-1997. The aims were (1) to determine if the increase was due to introduction of new strains, (2) to assess the geographic and age distribution of the cases, (3) to compare antibiotic sensitivity patterns of the current isolates with strains from the early 1990s. In 1993-1994, 15/19 (74%) of the cases for which information on age was available were in children =5 years; in 1995-1997, 80/179 (45%) of cases were in children =5 years and 99 (55%) in the older age range (P<0.02). From 593 cases in 1993-1997, 214 (36%) isolates were available for characterisation. Serogroup B was predominant in the early 1990s, but by 1997, serogroup C accounted for 46/72 (64%) of isolates and serogroup B for 25/72 (35%). Serogroup B was predominant in children =5 years (44/78, 56%) but only 19/99 (18%) of older children and adults (P=0.0000005). Sulfonamide resistance decreased from 10/22 (45%) in 1993-1994 to 27/192 (14%) in 1995-1997 (P<0.01). Multilocus enzyme electrophoresis of 70 strains obtained during this period identified the epidemic ET-15 clone in 24 (34.3)%. The profiles of the Greek ET-15 isolates were identical to C:2a:P1.2(P1.5) strains responsible for the epidemic in the Czech Republic which began in 1993. This genotype was not found in Greek strains isolated prior to 1993. We conclude that the increase in meningococcal disease is due to introduction of the epidemic serogroup C:2a:P1.2(P1.5) strain responsible for disease in the Czech Republic and Canada. Copyright (C) 1999 Federation of European Microbiological Societies.

Epidemiological studies indicate that breast-fed infants are at a decreased risk of sudden infant death syndrome (SIDS) compared to formula-fed infants. Increasing evidence suggests that infectious agents might be involved in some of these deaths, in particular bacteria which colonise mucosal surfaces and produce superantigenic toxins. One species implicated in recent studies of SIDS infants is Staphylococcus aureus. We tested the hypothesis that in comparison to infant formula, human milk might be a better inhibitor of binding of S. aureus to epithelial cells. In this study, two protocols were used for the binding assays which were assessed by flow cytometry: the in vitro method in which bacteria were treated with milk or formula, washed and added to epithelial cells; and a method more closely reflecting the competitive interactions in vivo in which cells, bacteria, and milk or infant formula were added at the same time. With the in vivo method, breast milk caused enhancement of bacterial binding to cells whilst infant formula caused inhibition; however, for the in vitro method, both human milk and infant formula caused consistent enhancement of binding. Flow cytometry and light microscopy studies indicated that the enhancement was due to the formation of bacterial aggregates. Human milk and infant formula preparations were also compared for components (antibodies or oligosaccharides) that could inhibit binding of S. aureus using the in vitro method. Human milk contained both IgA and IgG. Neither human milk nor infant formula contained oligosaccharides reactive with the Ulex europaeus lectin but both contained components that bound monoclonal antibodies to Lewisa and Lewisb antigens which can act as receptors for S. aureus. With both methods, synthetic Lewisa and Lewisb inhibited S. aureus binding in a dose-dependent manner. With human milk, however, the only component which showed a significant correlation with inhibition of binding was the IgA specific for the staphylococcal surface component that binds Lewisa. Both human milk and infant formula contain components which could potentially inhibit bacterial binding but only breast milk contains the IgA specific for the bacterial adhesin that binds Lewisa. Studies using the in vivo method suggest that protection associated with breast feeding in relation to SIDS could be due mainly to the formation of bacterial aggregates. The studies have implications for further research into constituents of infant formula. Copyright (C) 1999 Federation of European Microbiological Societies.

Recent studies on the aetiology of the Sudden Infant Death Syndrome (SIDS) have suggested that some of these deaths are the consequence of an overwhelming inflammatory response to the production of pyrogenic toxins from bacteria colonizing the upper respiratory tract, particularly the nasopharynx. The pyrogenic toxins of Staphlococcus aureus, one of the likelier bacterial candidates, are only produced in temperatures of over 37°C. This study examined nasopharyngeal temperatures in children. It is a preliminary study to develop an accurate means to measure how close to 37°C the nasopharyngeal temperature lies in infants at the age when SIDS deaths occur. Following a pilot study and power calculation, measurements of nasopharyngeal temperature were made on 30 apyrexial children aged 4-10 years and 30 adults with no nasal pathology, undergoing surgery under general anaesthesia, using an accurately sited thermocouple probe. The mean temperature in children (35.64°C) was significantly higher than in adults (34.01°C). Comparable measurements attempted with the same subjects awake gave similar results.

There is no convincing epidemiological or pathological evidence that particular infectious events cause sudden infant death syndrome (SIDS); therefore, we have explored the concept that ergy between bacterial endotoxins, exotoxins or viruses might elicit inflammatory responses during a period when the infant's do ine system is less able to 'damp down' cts of powerful mediators such as is factor or to maintain lu which is affected by these mediato his hypothesis is discussed with reference to the recent decline in the number of cot deaths. © 1995 Elsevier Science Ltd.

Necrobiosis lipoidica (NL), a skin disease, is associated with insulin-dependent diabetes mellitus (IDDM). Natural autoantibody (NAb) activity in sera from 16 patients suffering from NL, with or without IDDM, was compared to that in sera from 41 patients with IDDM and 43 healthy controls. Isotype-specific enzyme-linked immunosorbent assays (ELISAs) were used to detect NAbs against actin, myosin, keratin, desmin, troponin, tropomyosin, thyroglobulin, insulin, single-stranded DNA and the hapten trinitrophenyl. NAb activity was significantly higher in sera from patients with NL (either with or without IDDM), compared with that detected in sera from patients with IDDM which was similar to that of healthy individuals. High proportion of NL sera exhibited increased IgG anti-tropomyosin (69% anti-troponin, anti-desmin and anti-keratin (50% each), anti-insulin (44% and anti-trinitrophenyl (31% activities, as well as increased IgA and IgM anti-keratin activities (26% and 31% respectively). The great majority (88% of positive sera were polyreactive and contained NAbs, polyspecific and monospecific (as demonstrated by immunoadsorption studies), belonging to more than one isotype; there was no predominant serological reactivity pattern. In conclusion, increased NAb activity to cytoskeleton proteins is associated with the dermatological disease NL and not to the overlapping autoimmune disease (IDDM). The origin and significance of these NAbs is discussed. © 1995 Informa UK Ltd All rights reserved: reproduction in whole or part not permitted.

Because there is little evidence that invasive bacterial diseases contribute to cot deaths, most studies on infectious causes of SIDS have focused on viruses or toxin producing bacteria. Although epidemiological studies found marginally significant associations between influenza virus and SIDS, respiratory syncytial virus (RSV) was isolated from 90% of older infants with SIDS. There are conflicting reports that some toxigenic bacteria (Clostridium botulinum, Clostridium difficile, enterotoxigenic Escherichia coli and Staphylococcus aureus) might be implicated in cot deaths. S aureus are common micro-organisms and their toxins are very powerful. As the pyrogenic toxic shock syndrome toxin of S aureus can kill a previously healthy adult, it might easily kill a small infant. Based on our studies on susceptibility of infants to other infections, we suggest the following might be factors leading to colonisation of infants by toxin producing S aureus: - The Lewisa blood group antigen appears to act as a receptor for some micro-organisms. Epithelial cells expressing high concentrations of Lewisa bound appreciably more toxin producing S aureus than cells expressing low concentrations of the antigen. - Lewisa is expressed in secretions of nearly 90% of infants aged 3 months, the peak age for SIDS. - RSV infects about 50% of infants by the first year of life and it is often isolated from infants with SIDS. Studies in our laboratory indicate that RSV infected HEp-2 cells bind more toxin producing S aureus than uninfected controls.

The in vitro binding of four Helicobacter pylori strains to human gastric mucin was studied with an enzyme-linked immunosorbent assay. All four strains were found to bind to purified mucin. Neuraminidase treatment and nonspecific oxidation of mucin decreased bacterial adherence to the macromolecule. Mucin preparations were also found to inhibit attachment of H. pylori to HEp-2 monolayers.

Thirty isolates of Helicobacter pylori from gastric biopsies agglutinated human erthyrocyte suspensions. Crude mucin preparation derived from saliva of 20 different donors were examined for their ability to inhibit haemagglutination. All mucin preparations exhibited strong inhibitory activity. Removal of sialic residues from mucin preparations by treatment with neuraminidase resulted in a substantial reduction of their inhibitory activity. The mucin prepations had no bactericidal or aggregation activity for H. pylori. These results are discussed in the context of the role of mucins in colonization of the gastric mucosa by H. pylori. © 1990.

The proportion of non-secretors of ABH blood-group substances among Icelanders is one of the highest recorded for European countries. Dental caries prevalence is also very high. In this study of dental caries in young adults mean number of decayed, missing and filled teeth for secretors were 17.4 and for non-secretors 19.9 (P < 0.05). A majority of patients seeking free dental treatment in the Dental School were non-secretors (62.7%) significantly more than the proportion of non-secretors in the general population (36%; P < 0.01). It is postulated that blood group substances may interfere with the adherence of Streptococcus mutants to teeth. © 1989.

One of the innate defences against superficial infections by Candida species appears to be the ability of an individual to secrete the water-soluble form of his ABO blood group antigens into body fluids. There was a significantly higher number of non-secretors (48.9%) among 174 patients with either oral or vaginal candida infections compared with the proportion of non-secretors in the local population (26.6%). The protective effect afforded by the secretor gene might be due to the ability of glycocompounds in the body fluids of secretors to inhibit adhesins on the surface of the yeast. In attachment studies, preincubation of blastospores with boiled secretor saliva significantly reduced their ability to bind to epithelial cells. Non-secretor saliva did not reduce the binding and often enhanced the numbers of attached yeasts. Possible host-parasite interactions underlying the susceptibility of non-secretors to candida and other infections are discussed. © 1989.

Epidemiological studies on the associations between ABO blood group antigens, secretor status and susceptibility to infectious agents are summarized. Evidence for association of non-secretion with some autoimmune diseases for which infectious aetiologies have been proposed is also given. Several hypothesis are proposed to explain the host-parasite interactions underlying the epidemiological observations, and evidence to support or refute them is presented. © 1989.

Strains of Escherichia coli isolated from urine of secretors (242) and non-secretors (121) were compared for their serotype and their ability to express mannose-sensitive (MS) haemagglutinins and mannose-resistant (MR) haemagglutinins and to produce haemolysin. The results of the survey refuted our hypothesis that strains with characteristics associated with virulence, those with MR haemagglutinins and/or haemolysins, would be isolated more frequently from non-secretors. MR haemagglutinins were detected among 36.4% of isolates from secretors and 27.3% of isolates from non-secretors. Haemolysin production was detected among 19.8% of isolates from secretors and 12.5% of isolates from non-secretors. Both MR haemagglutinins and haemolysin were detected only on 12.4% of strains from secretors and 6.7% of strains from non-secretors. © 1989.

This study tested the hypothesis that the Lewis a blood group antigen found predominantly on the cells of non-secretors might be one of the receptors for Candida species. Binding of strain 3118C to epithelial cells from either secretor or non-secretor donors was not inhibited by treating the cells with anti-Lewis a or anti-Lewis b antisera. Binding of strain 3091 to non-secretor cell was inhibited by pretreating the cells with anti-Lewis a, but this was not observed for secretor cells. The results suggest that Lewis a might be one of the receptors for some yeast strains. © 1989.

In a study of 718 women referred for specialist investigation for recurrent urinary tract infections, 250 (34.8%, P<0.01) were non-secretors. The proportion of non-secretors among the women with renal scars (42.6%) was higher than that found for women with no evidence of renal scars (36.6%). Among 29 patients in whom symptoms began in childhood or adolescence, 51.7% were non-secretors. The proportion of non-secretors among individuals with renal scars in this study (42.6%) and that reported in the accompanying paper for Swedish children (40%) suggests that non-secretion might influence the pathogenic sequelae of these infections. Possible host-parasite interactions underlaying the increased proportion of non-secretors among women with recurrent urinary tract infections and those leading to development of renal scars are discussed. © 1989.

Epidemiological evidence is summarized for associations of ABO blood group and secretor status with susceptibility to invasive disease due to capsulate organisms responsible for the majority of bacterial meningitis. Host-parasite interactions that might underly these findings are proposed and evidence to support or refute them provided. © 1989.

Recognition of bacteria, antigen presentation and regulation of the immune response by the class II antigens of the major histocompatibility complex (MHC) are among the many factors that influence a host's response to microbial infection. 'Lectin-like' receptors on the macrophage membrane recognize a variety of bacteria by interaction with their cell-wall sugars. These receptors are susceptible to environmental factors and appear to be associated with the I-A subregion of the mouse MHC. Possible effects of this recognition system on the pathogenesis of microbial infection and reactive arthritides are considered.