Specific Serum IgG Research Articles

Adjuvant properties and colonization potential of adhering and non-adhering Lactobacillus spp following oral administration to mice.

This study aimed to determine whether adhesive strains of Lactobacillus possessed an increased ability to colonize the gastrointestinal tract and to examine the adjuvant capacities of these strains for the 50000 molecular-mass fragment C of tetanus toxin (TTFC) following oral administration. The three strains used in this study showed different patterns of adhesion to tissue from all regions of the gastrointestinal tract, with two strains adhering in high numbers and one strain showing negligible association with all tissue types. The colonization patterns in the gastrointestinal tract of C57BL/6 mice following oro-gastric dosing was also monitored, and it was found that adhesive Lactobacillus strains could be detected for at least 24 h, in association with either fecal material and/or with gastrointestinal tissue or contents. In addition, mice were given an oro-gastric dose of the lactobacilli (5 x 10(8) colony forming units) with TTFC (10 and 50 micro g), and the serum-specific IgM and IgG antibody responses monitored in serum. The adhesive strains, which persisted within the gastrointestinal tract for at least 24 h, showed enhanced antigen-specific serum IgG and IgM antibody responses in comparison to a non-adhesive strain that failed to be detected in the gastrointestinal tract. Adhesion to the gastrointestinal tract is a factor affecting the capacity of lactobacilli to persist within the gastrointestinal tract and to act as an adjuvant for orally administered antigen.

Vaccination for birch pollen allergy: Induction of affinity-matured or blocking IgG antibodies does not account for the reduced binding of IgE to Bet v 1

Specific allergy vaccination (SAV) is associated with increased levels of allergen specific IgG in serum. It is not clear, however, to what extent qualitative changes in allergen binding to IgG may be induced as well. We therefore analyzed the binding of the major allergen in pollen of birch ( Betula verrucosa) (Bet v 1), the major allergen in birch pollen, to serum IgG and IgE, separately and in competition. Sera from six birch pollen-allergic patients were obtained before and after 5 years of SAV, and binding was assessed with 125 I -Bet v 1. Before SAV, IgG bound more than eight times the amount of Bet v 1 compared with IgE, and together they accounted for more than 85% of the serum binding capacity. While SAV induced minimal changes in IgE binding, the IgG binding capacities increased 6–32 times. In contrast, the binding avidities ( K d 28–40 pM) changed less than 20%, pre- and post-SAV IgG provided similar inhibition of Bet v 1 binding to IgE at equimolar levels, and cross inhibition studies between IgG and IgE showed low inter-individual differences. Following SAV, all sera reduced Bet v 1 binding to CD23 + cells, correlating with reduced binding of Bet v 1 to IgE ( P<0.001). These results show that high avidity IgG of low inter-individual difference in Bet v 1 binding quality is the dominant binding factor of Bet v 1 in sera of birch pollen-allergic patients, and that SAV-induced inhibition of binding of Bet v 1 to IgE can be explained mainly or solely by increased amounts of IgG.

Adjuvant properties and colonization potential of adhering and non-adhering Lactobacillus spp. following oral administration to mice

This study aimed to determine whether adhesive strains of Lactobacillus possessed an increased ability to colonize the gastrointestinal tract and to examine the adjuvant capacities of these strains for the 50 000 molecular-mass fragment C of tetanus toxin (TTFC) following oral administration. The three strains used in this study showed different patterns of adhesion to tissue from all regions of the gastrointestinal tract, with two strains adhering in high numbers and one strain showing negligible association with all tissue types. The colonization patterns in the gastrointestinal tract of C57BL/6 mice following oro-gastric dosing was also monitored, and it was found that adhesive Lactobacillus strains could be detected for at least 24 h, in association with either fecal material and/or with gastrointestinal tissue or contents. In addition, mice were given an oro-gastric dose of the lactobacilli (5×108 colony forming units) with TTFC (10 and 50μg), and the serum-specific IgM and IgG antibody responses monitored in serum. The adhesive strains, which persisted within the gastrointestinal tract for at least 24 h, showed enhanced antigen-specific serum IgG and IgM antibody responses in comparison to a non-adhesive strain that failed to be detected in the gastrointestinal tract. Adhesion to the gastrointestinal tract is a factor affecting the capacity of lactobacilli to persist within the gastrointestinal tract and to act as an adjuvant for orally administered antigen.

Prior meningococcal A/C polysaccharide vaccine does not reduce immune responses to conjugate vaccine in young adults

The immune responses induced in young adults by a meningococcal A/C polysaccharide-diphtheria toxoid conjugate vaccine (Mcj) and a meningococcal A/C plain polysaccharide vaccine (Mps) were evaluated in unvaccinated subjects and those who had received either vaccine previously. 195 subjects aged 17–30 years received either Mps or Mcj. After 12 months, they were randomised again to receive a second dose of either vaccine. Serogroup specific serum bactericidal assay (SBA) titers and IgG antibody responses were assayed before and 4–8 weeks after primary and booster immunisation. Both vaccines were immunogenic in previously unvaccinated subjects. Administration of a dose of Mps after previous Mps or Mcj induced lower bactericidal titers to group C Neisseria meningitidis than those seen after a single dose of Mps. Bactericidal antibody responses to Mcj were not reduced in subjects who had previously received Mps.

Specific immunoglobulin E and immunoglobulin G antibodies to toluene diisocyanate‐human serum albumin conjugate: useful markers for predicting long‐term prognosis in toluene diisocyanate‐induced asthma

Our previous study reported that more than 50% of toluene diisocyanate (TDI)-induced asthma patients had persistent asthmatic symptoms even after complete avoidance. Although specific IgE (sIgE) has been detected in a portion of patients with TDI-asthma, a recent investigation suggests that the presence of serum specific IgG (sIgG), not sIgE, is more closely associated with positive bronchoprovocation test (BPT) results. To evaluate the possible role of sIgE and sIgG in predicting long-term prognosis of TDI-asthma. Forty-one TDI-asthma patients whose diagnosis was confirmed by TDI-BPT, and 20 unexposed healthy controls were enrolled. Both sIgE and sIgG to TDI-human serum albumin (HSA) conjugate were detected by ELISA. All patients with persistent asthmatic symptoms took anti-asthmatic medications during the follow-up period (mean: 67.5 months) and were instructed to avoid exposure to TDI. Airway hyper-responsiveness to methacholine (AHM) was monitored every year during the study period. The patients were classified into three groups according to changing patterns of AHM and asthmatic symptoms as follows: group I, no improvement with persistent asthmatic symptoms (n = 12); group II, partial improvement with persistent asthmatic symptoms (n = 13); group III, in remission (n = 16). Favourable prognosis was associated with a mild degree of AHM at initial diagnosis (P < 0.05). Although there were no significant differences in the prevalence of sIgE antibody to TDI-HSA conjugate among the three groups (P > 0.05), prevalence of sIgG in group I tended to be higher than in group II (0.05 < P < 0.1). However, the levels of sIgG were significantly higher in group I than in group II (P = 0.05), whereas levels of sIgE were significantly higher in group II than in group I (P = 0.014). No significant differences were noted in exposure duration, sex, age, atopic status, and total IgE level among the three groups (P > 0.05). This study confirmed that a favourable outcome is related to a mild degree of AHM and to low levels of sIgG to predict persistent asthmatic symptoms, it also suggested that the presence of high serum-specific IgE at initial diagnosis may represent a better prognosis.

Intranasal immunization with recombinant antigens associated with new cationic particles induces strong mucosal as well as systemic antibody and CTL responses

New cationic nanoparticles (SMBV™) were evaluated for use as a nasal vaccine delivery system for two recombinant proteins: HBsAg and β-galactosidase. Each protein was formulated with SMBV™ and intranasally administrated to non-anesthetized mice. In each model, the formulated protein induced high levels of specific serum IgG antibodies and cytotoxic T lymphocyte (CTL) responses. Moreover, specific IgA antibodies were found in nasal as well as in vaginal washes of intranasally immunized mice with the protein associated with SMBV™. In contrast, no IgG or IgA antibodies and no CTL were detected in mice immunized with free protein. The detection of a CTL response and an increase in both IgG1 and IgG2a antibodies in serum suggest that SMBV™ amplifies both Th1 and Th2 responses without modifying the Th1/Th2 profile of the immune response induced by the natural protein. These data demonstrate the high potential of SMBV™ for use as a nasal delivery system for sub-unit vaccines.

Incidence and prevalence of human group C rotavirus infections in Argentina.

The incidence of human group C rotavirus infections among children and adults in Buenos Aires was evaluated by enzyme linked immunosorbent assays (ELISA) based on recombinant group C VP6 protein (Cowden strain). A total of 976 stool samples taken from patients (ages 6 months to 15 years) with acute diarrhea were tested for the presence of group C rotavirus. Among these, only 10 (1.02%) were group C rotavirus positive by enzyme-linked immunosorbent assay (ELISA) confirmed by absorption with group C VP6 antibodies and by RT-PCR for both VP6 and VP7 genes. The average age (5.86 years) was significantly superior to that in group A-infected patients (1.63 years). Previous exposure to this virus was assessed by detecting specific IgG in sera taken from healthy individuals grouped by age. Of 844 sera tested, 425 (50.3%) were group C IgG positive by ELISA, confirmed by Western blot analysis. The rates of IgG positivity for group A and C rotaviruses during the first years of life indicated that infections with group C are frequent in older children (3-5 years), whereas group A infections are prevalent in infants and young children (6-18 months). This study shows that group C rotavirus infections in Argentine children occur later in life than group A and are relatively common in spite of the low detection rate of this virus.

Chronic urticaria with sensitization to Anisakis simplex: Which factors contribute to detectable specific IgG4 values?

61 Chronic Urticaria With Sensitization to Anisakis Simple~, Which Factors Contribute to Detectable Specific IgG4 Values? Francisco Vega de La Osada, Alvaro Daschner, Bego~a Gonzdlez Leza Hospital University La Princess, Madrid, Spain In our area a high proportion of patients with chronic urticaria are sensitized to Anisakis simplex (A.s.). In order to elucidate a possible diagnostic value for specific IgG4, patients with chronic urticaria and with measurable specific IgE values (>0,7 kU/1, Cap-FEIA, Pharmacia, Uppsala, Sweden) were divided into two groups: Group A was comprised of 23 patients with detectable specific IgG4 against A.s. and in group B 21 patients were included without detectable IgG4. Both groups were compared with respect to age, specific IgG against A.s. and duration of symptoms (mean values, standard deviation (SD), t-test) as well as for total and specific IgE against A.s. (median values, interquartile range (IQR) and Mann-Whitney). Spearman correlation coefficients were calculated between the mentioned parameters. Chi-square-test was used to compare the prevalence of Helicobacter-pylori infection (positive breath test), anarnnestic data of rhinoconjunctivitis or asthma as well as the prevalence of a suspected previous history of acute gastro-allergic Anisakiasis (acute urticaria/angioedema, abdominal pain and or nausea after intake of raw or undercooked fish) in both groups. Mean age was 44,2 (SD 16,5) years in group A and 44,0 (SD 13,4) years in group B. IgG4 levels in group A ranged from 177-6405 (median 869) lag/l. Mean specific serum IgG was higher in group A than in group B (12,1, SD 10,5 mg/l versus 6,7, SD 4,0 mg/1; p=0,05). Mean duration of symptoms did not differ in group A (20,4, SD 28,3 months) compared to group B (27,2, SD 33,7 months). Total IgE was higher in group A than in group B (median 241, IQR 125-382 kU/1 versus 149, IQR 82-192 kU/1, p=0,02). Also specific IgE was higher in group A (29,8, IQR 14-53 versus 4,5, IQR 1,5-14,4; p=0,001). If all patients were studied, IgG4 values correlated with total IgE (Rho 0,35; p=0,02), specific IgE (Rho 0,49; p=0,001 ) and specific IgG (Rho 0,51; p<0,001 ). If only those of group A were studied only specific IgG was correlated with specific IgG4 (Rho 0,71; p=<0,001). Seven of eight patients with suspected previous gastro-allergic Anisakiasis displayed detectable specific IgG4, compared to 12 of 27 patients who did not remember any previous fish-related symptoms (p= 0,032). Helicobacter-pylori infection or rhinoconjunctivitis/asthma did not significantly predispose the patients to belong to one of both groups. Some patients with acute urticaria/angioedema in the context of gastro-allergic Anisakiasis develop chronic urticaria, maintaining detectable specific IgG4 against A.s. However specific IgG4 levels are to be interpreted taking into account the levels of total IgE, specific IgE and specific IgG. Of these parameters, specific IgG seems to be more relevant, thus further studies should focus on other factors that influence specific IgG.

Antibodies, directed towards Campylobacter jejuni antigens, in sera from poultry abattoir workers.

Occupational exposure of susceptible humans to Campylobacter jejuni appears to result in resistance to disease. This is believed to be due to acquired protective immunity. To support this hypothesis the levels of C. jejuni-specific IgG and IgM antibodies were determined in sera from poultry abattoir workers. Such individuals are persistently exposed to C. jejuni, but apparently rarely acquire campylobacteriosis. Sera from 43 short-term workers (employed < or = 1 month), 78 long-term workers and 40 blood donors were investigated by ELISA. In 51 individuals a second serum sample, taken at least 1 month after the first, was also investigated. Eight workers had C. jejuni-positive faecal cultures and only one, a short-term worker, had symptoms of campylobacteriosis. There were significantly higher levels of specific IgG antibodies in long-term workers than in either of the other groups. There was no significant difference detectable in specific IgM antibody levels between any of the groups. The results provide supporting evidence that long-term exposure to C. jejuni induces circulating antibodies which reflect apparent reduced susceptibility to disease. Western blotting showed flagellin and polypeptides of 45, 40, 32 and 30 kD bound antibodies significantly more frequently by sera from long-term workers than short-term workers and blood donors. The most commonly detected antigens were the 40-kD (80%) and flagellin (55%). The results indicate that specific serum IgG responses induced by endemic exposure to C. jejuni might be directed towards a small number of protein antigens with apparently conserved epitopes.

L’allergie aux vaccins associés chez l’enfant. Une étude de 30 cas fondée sur les tests cutanés à lecture immédiate, semi-retardée et retardée, sur les dosages des anticorps spécifiques et sur les injections de rappel

Skin tests (prick and intradermal) were performed with vaccines containing diphtheria, pertussis, tetanus, polio and Haemophilus influenzae type b antigens (D.P.T.Pol.Hib), and with selected components of the vaccines in 30 children reporting reactions suggestive of allergy to these vaccines. Serum-specific IgE and IgG against components of the vaccines were also studied. Immediate responses in skin tests and specific IgE determinations strongly suggested the diagnosis of immediate-type hypersensitivity to tetanus or diphtheria toxoids in ten children (33.3%), including four of the six children with anaphylaxis, and six of the 16 children with urticaria and angioedema. In the other 20 children, immediate, semi-late and late responses in skin tests and specific IgE determinations were negative. Booster immunizations were given with monovalent or bivalent vaccines in 14 of these children, and were well tolerated. Our results suggest that most large local reactions and mild to moderately severe generalized skin reactions to multivalent vaccines are not allergic, but instead result from a nonspecific inflammatory reaction. However, our results show that toxoids may induce immediate-type hypersensitivity reactions in children, and suggest that skin tests with vaccines and vaccine components, and the determination of specific IgE against vaccine components, are of diagnostic value in children with anaphylaxis, and immediate and accelerated urticaria and angioedema induced by booster injections of multivalent vaccines.

Eimeria infections in cows in the periparturient phase and their calves: oocyst excretion and levels of specific serum and colostrum antibodies

Faecal Eimeria oocyst excretion and levels of antibodies to first generation merozoite antigen of E. bovis in sera and colostra were followed in 86 and 70 cow–calf pairs in northern (group EF) and central Germany (group H), respectively, over periods of 3 weeks before to 3 weeks after calving in cows and from birth to an age of 63 days in calves. Oocysts were found in 30 and 7.7% of cows in groups EF and H, respectively. They belonged to 10 (group EF) and four Eimeria spp. (group H) with E. bovis, E. ellipsoidalis, E. auburnensis and E. zuerni as the most frequently occurring species. Prevalence and intensity of oocyst excretion varied with time resulting in peak values around the date of parturition, particularly in the case of E. bovis. Peak values at the time of parturition were also seen in case of strongyle egg excretion. Seven (group H) and nine Eimeria spp. (group EF) were found in the calves. The predominant species E. ellipsoidalis, E. zuerni, E. bovis and E. auburnensis were detected for the first time earlier after birth (3–5 weeks) than the others. The prevalence of Eimeria infections increased to 67.1% (group EF) and 50.1% (group H) 9 weeks after birth. Specific IgM and IgA antibody levels (the latter only determined in group EF) in cow sera remained almost constant throughout the observation period, whereas IgG 1 and IgG 2 levels were reduced at the time of parturition. Levels of specific antibodies in sera and colostra were significantly correlated. Except IgM antibodies, significant inverse correlations were found in cows between intensity of infection with E. bovis and specific serum IgG (group H) and IgG 2 (group EF) antibodies. Antibodies to E. bovis were detected in calves sera only after colostrum intake with significant correlations between levels in calves sera and colostra. Levels decreased, starting within the first week of life (most conspicuously in case of IgM and IgA) until the third week. Subsequently, but except IgG 1 antibody concentrations increased until the end of the observation period. Interrelations between antibody levels and the total amount of E. bovis oocysts excreted by the calves until the ninth week of life varied with the age of the animals. Inverse relationships in the first 3 weeks of life as suggested by negative correlation coefficients could not be proven statistically. Thus, there is no unambiguous proof for immunoprotection of calves against E. bovis via maternal immunity. Considering antibody levels in the 3–9 weeks old calves significant direct correlations with E. bovis oocyst excretion were found in case of IgM, IgG 2 and IgA, reflecting an active immune response of young calves to coccidial infection.

Human salivary immunoglobulin and antigen-specific antibody activity after tonsillectomy.

The importance of the lymphoid tissue collectively known as Waldeyer's ring, which includes the palatine, lingual and nasopharyngeal tonsils, in the induction and contribution of specific antibody responses in human saliva is not clear. The purpose of this study was to determine whether salivary immunoglobulin A (IgA) levels differ in quantity and quality between subjects who have had a tonsillectomy and age, sex and race-matched controls. Parotid saliva, whole saliva, and blood serum samples were collected from 25 volunteer children who had undergone tonsillectomy (T-) within 6-14 months of sampling and from 25 age, sex and race-matched controls. The levels of total IgA (and subclasses) in saliva, and of antigen-specific salivary IgA and serum IgA and IgG antibodies to 4-9 relevant antigens were analyzed by ELISA. No significant difference was observed in the mean total IgA and IgA subclass levels in parotid and whole saliva, although the mean levels for children with a T- were slightly lower. Children with a T- had significantly higher parotid salivary IgA and IgA1 specific/total activity than controls. The total and specific whole saliva IgA and the specific serum IgA or IgG activities were not significantly different from controls. These results indicate an association between the removal of tonsils and increased levels of specific IgA activity in parotid saliva within the first year after a T-.

Th1 adjuvant N-acetyl-D-glucosamine polymer up-regulates Th1 immunity but down-regulates Th2 immunity against a mycobacterial protein (MPB-59) in interleukin-10-knockout and wild-type mice.

Treatment of mice with heat-killed (HK) Mycobacterium bovis BCG or 1- to 10-microm chitin particles (nonantigenic N-acetyl-D-glucosamine polymers) is known to induce innate immune responses, including gamma interferon (IFN-gamma) production, which plays a Th1 adjuvant role. However, HK BCG further induces prostaglandin E2-releasing spleen macrophages (Mphi) (PGE2-Mphi), which potentially inhibit Th1 adjuvant activities. We found that chitin particles did not induce PGE2-Mphi formation. To further assess whether chitin has Th1 adjuvant effects, interleukin-10 (IL-10)-knockout (KO) mice and their wild-type (WT, C57BL/6) controls were immunized with a 30-kDa MPB-59 mycobacterial protein mixed with chitin. Immunization with MPB-59 alone induced Th2 responses, characterized by increases in total serum immunoglobulin E (IgE) and specific serum IgG1 levels and spleen Th2 cells producing IL-4, IL-5, and IL-10. No IFN-gamma-producing spleen Th1 cells, specific serum IgG2a, or delayed-type hypersensitivity (DTH) footpad reactions were detected. On the other hand, chitin-MPB-59 immunization significantly increased spleen Th1 responses, DTH reaction, and serum IgG2a levels along with decreases of Th2 responses. The magnitude of these Th1 adjuvant effects was greater in IL-10-KO mice than in WT mice. In contrast, immunization with HK BCG-MPB-59 showed little or no Th1 adjuvant effect. These data indicate that chitin has a unique Th1 adjuvant effect on the development of Th1 immunity against a mycobacterial antigen. IL-10 down-regulates the adjuvant effect of chitin.

Spatial distribution of seropositivity to the causative agent of granulocytic ehrlichiosis in dogs in California.

To assess spatial and temporal patterns of seroprevalence among dogs in California to the causative agent of granulocytic ehrlichiosis (GE). Sera of 1,082 clinically normal dogs from 54 of 59 counties in California in 1997 to 1998. Serum-specific IgG reactivity to Ehrlichia equi was assessed by use of an immunofluorescent antibody assay, using E. equi-infected horse neutrophils as substrate. Data were analyzed, using a geographic information system. Spatial analysis of seroprevalence included first order Bayesian analysis of seroprevalence and second order analysis of clustering by K-function and Cuzick-Edwards tests. Monthly seroprevalence among dogs was examined by use of regression on monthly densities of Ixodes pacificus adults and nymphs. Seroprevalence among dogs to E. equi was 8.68%. Data were seasonally bimodal with highest prevalence in winter (when adult ticks were abundant) and a secondary peak in late spring (corresponding to nymphal ticks). Humboldt County had the highest seroprevalence (47.3%), and other northern coast range counties had seroprevalence from 15 to 30%. The patchy distribution of exposure to Ehrlichia organisms is a subset of the distribution of the tick vector. This may reflect enzootic cycles or climatic or historical factors that limited the range of the disease. Dogs, horses, and humans from north coast range counties in California are at increased risk of GE. These data provide a background for assessing risk of infection in horses and dogs, depending on geographic location. Dogs may be sentinels for assessing risk of GE in humans.

Nasal immunization with subunit proteosome influenza vaccines induces serum HAI, mucosal IgA and protection against influenza challenge

The immunogenicity of a mucosally delivered subunit influenza vaccine was assessed in mice. Split influenza virus vaccine (sFlu) was formulated with proteosomes (Pr-sFlu), administered intranasally, and the induced immunity was compared with the responses elicited by sFlu alone given either intramuscularly or intranasally. Intranasal (i.n.) immunization with Pr-sFlu induced specific serum IgG and hemagglutination inhibition (HAI) titers comparable to or better than those induced by intramuscular (i.m.) sFlu, and in contrast to sFlu alone, i.n. Pr-sFlu also induced high levels of influenza-specific IgA in lung and nasal washes. Mice receiving i.n. Pr-sFlu were completely protected against live virus challenge, as were mice immunized by injection with sFlu alone. The i.n. Pr-sFlu elicited cytokine responses polarized towards a type 1 phenotype whereas those elicited by sFlu alone were of a mixed type 1/type 2 phenotype. The data strongly suggest that i.n. proteosome-formulated influenza antigens are highly effective and are excellent candidates for a non-invasive human vaccine.

Trichinella spp. in ostrich meat: a public health risk?

In the present work the biological behaviour of T. spiralis and T. pseudospiralis in ostriches is reported. Oral infections were performed in eight ostriches with two infective doses (10,000 and 80,000 larvae) for each species of Trichinella. On day 0, 30 and 60 p.i. blood samples were collected to assay the serum changes concerning specific muscle enzyme activities and total proteins. The immunological study, to determine specific IgG in sera, was conducted employing a monoclonal blocking ELISA. From the carcasses of sacrificed animals, samples of various muscle tissues were examined by the digestion method and by standard histopathologic procedures. The study showed a low susceptibility of the ostriches to T. pseudospiralis; preferential sites of larval distribution were muscle tissues of the legs. T. spiralis could be found in muscle tissues only when a high number of larvae were inoculated. Immunological reactivity was found only in animals infected with higher doses of T. pseudospiralis.

Prevalence and association between herpes simplex virus types 1 and 2-specific antibodies in attendees at a sexually transmitted disease clinic.

Seroprevalence of herpes simplex virus type 1 (HSV-1) and HSV-2 was determined in 1993 and 1998 in a randomly selected study group of 1024 and 654 attendees, respectively, at the sexually transmitted disease (STD) clinic of the University Hospital Rotterdam-Dijkzigt, The Netherlands. Correlations of HSV-1 and HSV-2 seropositivity were investigated. The relationship between HSV-1 and HSV-2 antibodies was also studied. Data were collected in a cross-sectional study from February 1993 until February 1994 and from January 1998 until December 1998. Glycoprotein G (gG) HSV type specific serum IgG was determined. Seroprevalence of HSV-1 was 68% versus 59% (1993 versus 1998, chi(2)-test P < 0.001), of HSV-2 it was 30% versus 22% (1993 versus 1998, chi(2)-test P < 0.001). Using logistic regression analyses, HSV-1 and HSV-2 seropositivity were significantly associated with age and ethnicity in both groups. In 1993, HSV-1 seropositivity also correlated with lower level of education and female gender, whereas in 1998 it correlated with 'number of sexual partners in the past 6 months' and 'present diagnosis of STD'. In both groups, HSV-2 seropositivity was also more prevalent in females and related to sexual lifestyle variables. In an exposure-disease model, HSV-1 seropositivity was not correlated with HSV-2 seropositivity (odds ratio 1993 = 1.1, 95% CI : 0.8--1.7; odds ratio in 1998 = 1.0, 95% CI : 0.5--1.8). Seroprevalence of HSV-1 and HSV-2 is falling among STD clinic attendees in Rotterdam. A changing pattern of risk factors for HSV-1 seropositivity indicates increasing sexual transmission of HSV-1. Seropositivity for HSV-2 correlated with known risk factors. A previous HSV-1 infection does not reduce susceptibility to subsequent genital HSV-2 infections.

Effect of pre-existing immunity for systemic and mucosal immune responses to intranasal immunization with group B Streptococcus type III capsular polysaccharide-cholera toxin B subunit conjugate

The effects of priming with a group B Streptococcus type III capsular polysaccharide (GBS CPS III)-recombinant cholera toxin B subunit (rCTB) conjugate, purified GBS CPS III or rCTB alone on the systemic and mucosal immune responses to CPS III after intranasal (i.n.) immunization were investigated in mice. Priming with purified GBS CPS III followed by boosting with GBS CPS III-rCTB conjugate or priming with the conjugate followed by boosting with free CPS induced comparable levels of specific IgG and IgA in both serum and in lungs and vagina. However, i.n. immunization comprising both priming and boosting with conjugate was superior to priming with CPS and boosting with conjugate or the reverse, especially with regard to inducing mucosal IgA anti-CPS responses. All the immunization schemes, except priming and boosting with free CPS, induced high and similar levels of IgG1 in serum. In contrast, mice primed with free CPS III and then boosted with CPS III-rCTB conjugate by the i.n. route failed to produce significant levels of IgG2a, IgG2b and IgG3 in serum, at difference from mice primed with the conjugate and boosted with either conjugate or free CPS. Pre-immunization with rCTB either i.n. or i.p. did not suppress specific serum IgG responses induced by GBS CPS III-rCTB conjugate intranasally, but did inhibit serum and especially mucosal IgA responses. Our findings suggest that priming with CPS affects the distribution of IgG subclasses to GBS CPS and that pre-existing anti-carrier rCTB immunity can have an inhibitory effect on mucosal immune responses elicited by the conjugate vaccine given by the i.n. route.

Development and evaluation of an antibody capture ELISA for detection of IgG to Epstein-Barr virus in oral fluid samples

The development of an EBV IgG antibody capture ELISA (GACELISA) for detection of EBV viral capsid antigen specific IgG in oral fluids is described. The assay was optimised and evaluated using paired serum and oral fluid samples from healthy laboratory staff ( n=82) and oral fluids collected either for routine measles, mumps, and rubella testing ( n=629) or for an epidemiological study of atopic dermatitis ( n=252). Statistical analysis by mixture modelling was used to determine the GACELISA cut-off and to estimate the sensitivity and specificity of the assay. Sensitivity and specificity was also assessed by comparing the results of immunofluorescence assay for EBV specific IgG in serum with those of GACELISA in 82 matching oral fluids. Compared to serum immunofluorescence assay, oral fluid GACELISA was found to have a sensitivity of 82.2 and 88.9% specificity with these samples. Mixture modelling, predicted the GACELISA to be 88.4% sensitive and of 99.4% specific. The prevalence of antibody to EBV in oral fluids was found to be 73.8% in laboratory staff, 34.4–73.9% in measles, mumps, and rubella patients and 22.2% in atopic dermatitis study participants. A robust, reliable and reproducible EBV GACELISA has been developed which will be a useful tool for epidemiological investigations.

Fecal shedding of hepatitis A virus in Indian patients with hepatitis A and in experimentally infected Rhesus monkey

Hepatitis A is highly endemic in India. The surveillance reports for the disease from this region are primarily based on the demonstration of hepatitis A virus (HAV) specific serum IgM and IgG antibodies. The present study was conducted to assess the presence and duration of fecal shedding of HAV in patients with hepatitis A and in an experimentally infected rhesus monkey. Nested reverse transcription polymerase chain reaction (RT-PCR) was applied to fecal specimens from 67 sporadic cases of hepatitis A. Recent infection with HAV in these cases was evidenced by the presence of serum anti-HAV IgM. Fecal HAV RNA positivity was observed in nearly 40% patients. The proportion of HAV RNA positivity in fecal specimens obtained within the first week (36.58%) was not different from those collected in 2–12 weeks post onset (42.42%) ( P>0.05). A significant number of HAV RNA positive stool specimens showed presence of full virus particles by immune electron microscopy (IEM). Extended fecal shedding of HAV could be a major contributory factor for high circulation of virus thereby maintaining hyperendemicity of the disease. One of the IEM positive samples was inoculated into an anti-HAV negative rhesus monkey. Serum alanine amino transferase levels of the monkey remained within the normal limits. However, HAV RNA positivity in the feces was noted from 3 to 50 days post inoculation. The monkey seroconverted to anti-HAV IgM on day 31. This study records prolonged excretion of HAV in humans as well as in experimentally infected rhesus monkey.