The prevalence of intestinal parasites in dogs from Prague, rural areas, and shelters of the Czech Republic

The prevalence of intestinal parasites was evaluated by examination of dog faecal samples in the Prague city centre, agricultural areas, and two shelters. The overall prevalence of parasites (i.e., protozoa and helminths, mentioned below) in Prague was 17.6%. Toxocara canis was the most common parasite, and was recovered from 6.2% of dogs, followed by Cystoisospora spp. (2.4%), Cryptosporidium spp. (1.4%), Trichuris sp. (1.1%), Taenia-type (1.0%), Giardia spp. (0.1%), Toxascaris sp. (0.9%), Dipylidium sp. (0.7%), Sarcocystis spp. (0.6%), Capillaria spp. (0.6%), Neospora/Hammondia spp. (0.5%), Ancylostoma sp. (0.4%), Uncinaria sp. (0.4%), and Spirocerca sp. (0.2%). The prevalence of infections with helminths and protozoans in two animal shelters in Prague was examined at the dog's admittance ir reception to the shelters and during housing. T. canis eggs (6.5%), Cystoisospora (4.4%), and Giardia (3.3%) cysts were the most prevalent. Significant increases in the prevalence of some parasites were found after a stay in the shelter. Giardia spp. showed an 11-fold increase in prevalence of dogs placed in the shelters for a longer time; Cryptosporidium spp. had a 7-fold increase, Capillaria spp. a 5-fold, Spirocerca sp., Neospora/Hammondia spp., and Cystoisospora spp. a 4-fold increase over dogs examined at the time of admittance to the shelter (p<0.01). Dog in rural areas were infected significantly more frequently (p<0.01) than those in Prague. In 540 faecal samples from rural areas, the overall prevalence of parasites (i.e., protozoa and helminths mentioned below) was 41.7%. The prevalence of T. canis was 13.7%, followed by Cystoisospora spp. (8.0%), Taenia spp. (3.5%), Sarcocystis spp. (3.0%), Giardia spp. (2.2%), Cryptosporidium spp. (2.0%), Trichuris sp. (1.7%), Toxascaris sp. (1.7%), Dipylidium sp. (1.3%), Neospora/Hammondia spp. (1.3%), Spirocerca sp. (1.1%), Uncinaria sp. (0.9%), Ancylostoma sp. (0.7%), and Capillaria spp. (0.6%). Examinations of dogs in urban and rural areas showed, with the exception of Trichuris sp. in Prague, a higher occurrence of nematode infection in autumn, notably T. canis (chi2>8.3, d.f.=3, p<0.04).

Serum antibody isotype responses of Fasciola-infected sheep and cattle to excretory and secretory products of Fasciola species

This study investigated the immunoglobulin isotype responses of sheep and cattle chronically infected with Fasciola hepatica and Fasciola gigantica to adult F. hepatica excretory/secretory products (Fh-ES) or F. gigantica excretory/secretory products (Fg-ES), respectively. An antibody enzyme-linked immunosorbent assay (Ab-ELISA) was used to determine serum antibody (total Ig, IgG(1), IgM, IgG(2) and IgA) responses. At necropsy, the mean number of flukes recovered was lower in cattle than in sheep. All F. hepatica and F. gigantica infected sheep and cattle showed an increased total Ig levels from 3 to 4 weeks post-infection (wpi). Among isotypes IgG(1) was most dominant while IgM was the earliest (2 wpi) to be detected in both sheep and cattle infected with both F. hepatica and F. gigantica animals. IgG(2) response was early (2 wpi) in sheep infected by F. hepatica but there was no response in sheep infected with F. gigantica. There was a late and strong IgG(2) response in cattle infected with both flukes. The IgA isotype showed an early and a clear biphasic response in sheep with F. hepatica but was less pronounced in F. gigantica infected sheep. While IgA response to Fh-ES was noticed 5 wpi in F. hepatica infected cattle, it appeared much later (21 wpi) in those infected with F. gigantica. The dominance of IgG(1) isotype in infected sheep and cattle suggest an associated Th2 response. This early response to adult Fasciola spp. ES antigen suggests an early exposure to the antigen presumably through the cross-reacting ES products of juvenile flukes. There is clearly difference in IgG(2) isotype response in cattle (resistant) compared to sheep (susceptible). The late IgG(2) response in cattle may suggest late Th1 involvement in bovine cellular responses to adult Fh-ES/Fg-ES.

Kinetics of Taenia solium antibodies and antigens in experimental taeniosis

Two groups of hamsters were infected with Taenia solium cysticerci, one of which was suppressed with methyl-prednisolone acetate on the day of infection and every 14 days thereafter. The other did not receive steroid treatment. Faecal and serum samples were taken prior to infection and then at weekly intervals. Parasite circulating- and coproantigens were detected by a capture ELISA with rabbit polyclonal antibodies against T. solium tapeworms. IgG antibodies in serum and in faecal supernatants were detected by ELISA with excretory-secretory products of T. solium adults recovered from hamsters. Infections remained up to 17 weeks in suppressed hamsters, but after week 11 no tapeworms were found in non-suppressed hosts. T. solium coproantigens in both groups of hamsters were positive from the 1st week post-infection (wpi) until the tapeworms were rejected. Circulating antigens were detected only in non-suppressed hamsters from the 3rd wpi until 1 week before T. solium was eliminated. All infected hamsters developed serum IgG antibodies against tapeworms which were detected from the 2nd wpi and decreased slowly after T. solium expulsion. Specific IgG in faecal supernatants was detected from the 3rd wpi only in non-suppressed hamsters. When suppression was stopped, coproantibodies could also be detected. The presence of IgG antibodies indicates that tapeworms induced an immune response in the experimental host and that when hamsters were suppressed with corticosteroids the immune response was impaired and did not allow the detection of IgG coproantibodies. This indicates, in addition, that the passage of T. solium antigens from the small intestine to the circulation was blocked.

Antibody responses in onchocerciasis as a function of age and infection intensity

Onchocerciasis is caused by the filarial nematode Onchocerca volvulus and is a major public health problem in West and Central Africa. With only partial and long-term treatment currently available, there is a need to develop a suitable vaccine. We analysed the antibody response to infective L3 larvae because this stage is thought to be associated with host protective immunity. In addition, we have related our findings to the age, gender and current infection intensity of our participants: variables that may significantly influence antibody production. Interestingly, whilst 90% of our study group were seropositive for adult specific immunoglobulin (Ig)E, only 23% produced L3 specific IgE. This is in contrast to IgG4 where seropositivity was comparable at 96% and 92%, respectively. Furthermore, IgG levels were significantly affected by age and the intensity of infection but unaffected by host gender. This finding is independent for the IgG subclass (IgG1, IgG2, IgG3 and IgG4) and its specificity (L3 versus adult antigen). In summary, we show that L3 larvae induce little specific IgE and the antibody response shows a different isotype balance than that against adult antigens. Both host and parasite variables can influence antibody production in this disease.

Clinical Features of Paragonimiasis Cases Recently Found in Japan: Parasite‐Specific Immunoglobulin M and G Antibody Classes

We retrospectively analyzed clinical features in 30 patients who were referred to our laboratory and given a diagnosis of Paragonimus westermani infection in 1999. Our results indicate that pleurisy with eosinophilia and dominant immunoglobulin (Ig) M antibody are characteristic features of the early stage of paragonimiasis, whereas IgG antibody is dominant in the late stage. Thus, in addition to tests for parasite-specific IgG antibody, tests for IgM-class antibody should always be considered for patients with pleurisy in whom paragonimiasis is suspected.

Serological investigation in children infected with Ascaris lumbricoides

The study included 260 hospitalised children with suspected infection with human ascaris. In serological diagnostics a protein antigen obtained from Ascaris lumbricoides was used. ELISA method was applied. IgG antibodies were detected. Positive results were found in 15% of the examined children. No relation to the gender or demographic conditions was found. The most frequently observed symptoms in the patients with Ascaris lumbricoides were: abdominal pain--87%, diarrhoea 15%. In 31% of the cases eosinophilia was found. Scatoscopy was carried out for all the patients, using the PARASEPT system and Kato and Miura methods as well as decantation and flotation. The examination, which was repeated three times, did not show cysts or eggs. Serological investigation exhibits higher sensitivity than the traditional methods. Their use in recognising ascariasis in humans significantly facilitates diagnostic procedures, especially in the lung phase of the disease, the larval stage or in cases of infection with an individual parasite, when the faeces samples do not contain the eggs. Serological investigation is also useful in all cases of suspected VLM.

Antibody responses to the fucosylated LacdiNAc glycan antigen in Schistosoma mansoni-infected mice and expression of the glycan among schistosomes

Infections of animals with parasitic worms, such as Schistosoma mansoni, induce humoral immune responses to carbohydrate antigens, raising the possibility that such antigens might be useful targets for the development of vaccines and new diagnostic approaches. Here we describe the identification of fucosylated LacdiNAc (LDNF) [GalNAc beta 1-4(Fuc alpha 1-3)GlcNAc-R] as a new carbohydrate antigen in S. mansoni that induces humoral immune responses in infected mice. The presence of antibodies was determined by ELISA using a neoglycoconjugate synthesized to express LDNF sequences. Sera from S. mansoni-infected, but not uninfected, mice contain IgM, IgG, IgA, and IgE antibodies to LDNF. The IgG antibodies are primarily of the IgG1 and IgG3 subclasses, with no detectable levels of the complement-fixing IgG2a and IgG2b isotypes. An IgM monoclonal antibody, designated SMLDNF1, was generated from the spleens of S. mansoni-infected mice, and the antibody exhibits specific recognition of LDNF sequences, but not other fucosylated glycans tested. Immunocytochemical analysis demonstrates that LDNF antigens are localized on the tegumental surface of adult S. mansoni. Western blot analysis indicates that LDNF sequences are expressed on numerous high-molecular-weight glycoproteins from the three major human schistosome species, as well as the bird schistosome Trichobilharzia ocellata. The identification of LDNF antigen on the tegumental glycoproteins of schistosomes and the ability to synthesize LDNF conjugates should aid in the development of glycan-based vaccines and immunodiagnostic tests for schistosomiasis and in determining the role(s) of the glycans in worm development and pathogenesis.

IgG-subclass antibody responses and the natural history of hepatic cystic echinococcosis in asymptomatic patients

Given that cystic echinococcosis (CE) is a serious clinical problem in endemic countries, there is still relatively little information available on the natural history of the human disease. The aim of the present study was to correlate serological status with pathology, in ultrasound-characterised, asymptomatic cases of human CE. Serum concentrations of IgG reacting with antigen B from cyst fluid and of similarly specific IgG1, IgG2, IgG3 and IgG4 were determined by ELISA and further investigated by immunoblotting. CE cases with simple cysts (Type I), or cysts with clear laminations and daughter cysts (Types II and III) exhibited elevated IgG4 seropositivity, whereas concentrations of specific IgG1 and IgG4 declined in CE cases characterised by cyst infiltration or calcifications (Types IV and V). The responses of each specific IgG subclass were used, in association with an ultrasound classification, to try to develop an immunoserological natural-history profile of CE in asymptomatic patients. Specific IgG4 antibody responses were particularly associated with the evolutive phase of CE (Types I, II and III), whereas the IgG1, IgG2 and IgG3 responses tended to be associated with the involutive phase (Types IV and V). These results indicated that an IgG4 antibody response was associated with (or was a marker for) cystic development, growth and disease progression, whereas the IgG1, IgG2 and IgG3 responses occurred predominantly when cysts became infiltrated or were destroyed by the host. The findings support the view that evolutive and subsequent involutive phases occur in untreated CE.

Parasite-specific antibody profile in human fascioliasis: application for immunodiagnosis of infection

The antibody isotype response to an adult Fasciola worm antigen preparation (FWAP) was examined in sera from 60 Egyptians with parasitologically confirmed fascioliasis by an ELISA. The FWAP-specific IgG1 and IgG4 antibodies were found in 97-100% of the patients. The ratio of the mean absorbance values between infected patients and healthy controls was 9.7 and 29.7 for IgG1 and IgG4 antibodies, respectively. The IgM, IgA, IgG2, and IgG3 antibodies were less dominant. In contrast to IgG1 antibodies, which were often detected in sera from patients infected with Schistosoma, Echinococcus granulosus, Ascaris lumbricoides, Ancylostoma duodenale, or Hymenolepis nana, FWAP-specific IgG4 antibodies were detected exclusively in the sera of patients with fascioliasis. The data thus support the conclusion that an IgG4/ELISA with crude FWAP as antigen may be used for sensitive and accurate immunodiagnosis of human fascioliasis.

Polarization of the immune response to the single immunodominant epitope of p38, a major Schistosoma mansoni egg antigen, generates Th1- or Th2-type cytokines and granulomas

In schistosomiasis mansoni, helminth eggs secrete soluble egg antigens (SEA) that induce T-cell-mediated granulomatous tissue responses. The cloned 38-kDa peptide (p38) of SEA was shown to induce and elicit Th1-type responsiveness in H-2(k) mice. Subsequently, the immunodominant T-cell epitope (P4) of p38 was shown to elicit pulmonary granuloma formation and Th1-type cytokine production in sensitized or infected mice. Here, we report that the immune response to p38 or P4 can be polarized to a Th1 or Th2 profile when the peptides are presented intraperitoneally in soluble recombinant interleukin-12 (IL-12) or alum adjuvant, respectively. The Th1 or Th2 profile was verified by cytokine secretion, enzyme-linked spot assay, and antibody isotype characterization. Importantly, the polarized immune response generated two types of pulmonary granulomas around injected P4-coated beads. The type 1 granulomas were smaller and contained mononuclear cells and occasional thin strands of deposited collagen. In contrast, the type 2 lesions were larger and contained mononuclear cells, large numbers of eosinophils, and several thick bands of deposited collagen. By reverse transcription-PCR cytokine, message in the type 1 granuloma-bearing lungs was found for gamma interferon, tumor necrosis factor alpha, and inducible nitric oxide synthase but not for IL-4 or IL-5. Conversely, lungs with type 2 granulomas had message only for IL-4 and IL-5. These results show that in the proper cytokine environment, the response to a strong Th1 inducer peptide can be deviated to a Th2 profile.

[Detection of different class (subclass) antibodies in sera of patients with schistosomiasis japonica for diagnosis and efficiency evaluation]

The subclass antibodies against IgG1, IgG3 and IgG4 in sera of the patients with chronic Schistosomiasis japonica were detected before treatment, and after treatment--6 and 12 months respectively, using Biotin-Avidin-ELISA (BA-ELISA) established by purified 31/32 KD antigen from the adult worms. At the same time IgG1 and IgM were examined by the standard ELISA. False positive reaction with normal control and cross reaction with other parasitic diseases have not been observed. The IgG1 and IgG3 subclasses showed high sensitivity and specificity and reduced quickly 6 months after treatment. These results indicate that the level of specific IgG1 and IgG4 to the 31/32 KD adult worm protein has high value for diagnosis of Schistosomiasis japonica and evaluation of the curative efficiency of the disease.

Specific immunoglobulin measurements related to exposure and resistance to Schistosoma mansoni infection in Sudanese canal cleaners

The present work comprises a longitudinal study of Schistosoma mansoni infection in occupationally hyper-exposed canal cleaners in the Sudan and the influence of chemotherapy on humoral immune parameters. The study groups included chronically infected canal cleaners (n = 19), newly recruited canal cleaners (n = 17), normally exposed adults (n = 31), school children (n = 46) and Sudanese negative controls (n = 48). Previous studies of the same canal cleaners have demonstrated that chronically infected canal cleaners were more resistant to reinfection than newly recruited canal cleaners. ELISA was used to detect specific IgE and IgG subclasses in response to whole worm antigen (WWH) and soluble egg antigen (SEA) before and 3 months after praziquantel treatment in the groups of canal cleaners and before and 1 year after treatment in normally exposed adults. When intensity of infection was correlated with IgE antibody response, the resistant group of canal cleaners (those who stopped passing ova after treatment) showed a significant positive correlation between intensity of infection and specific IgE to WWH (Spearman's correlation coefficient = 0.49, P < 0.05) compared with a highly significant negative correlation in the susceptible group (acquired new infection after treatment, Spearman's correlation coefficient = -0.94, P < 0.01). Normally exposed adults and school children had significantly less specific IgE to WWH than canal cleaners, while chronically infected canal cleaners had significantly higher levels of specific IgG1 to WWH than newly recruited canal cleaners and school children, and significantly higher levels of specific IgG4 to WWH than school children. There was a significant increase in specific IgG1 and IgG4 to WWH, 3 months after treatment, in newly recruited canal cleaners and a significant decrease, 1 year after treatment, in normally exposed adults. None of the groups studied after treatment showed a significant change in their specific IgE to WWH. Normally exposed adults had significantly lower levels of specific IgE to SEA than newly recruited canal cleaners, and significantly lower levels of specific IgG1 to SEA than other infected groups. Both newly recruited canal cleaners and school children had significantly higher levels of specific IgG2 to SEA than persons in other groups. Only small differences between groups were observed with regard to specific IgG3 and IgM to SEA. Specific IgG4 to WWH and SEA showed different patterns after treatment between the resistant and susceptible groups of canal cleaners. The resistant group maintained the same level of IgG4 to WWH after treatment compared with a significant increase in the susceptible group. On the other hand, levels of specific IgG4 to SEA showed a highly significant decrease after treatment in the resistant group. In contrast, the same antibody subclass increased after treatment in the susceptible group. Generally, results show an association between IgE and IgG1 responses to WWH and resistance to reinfection. In contrast, an association was observed between IgG2 and IgM responses to SEA and susceptibility to reinfection.

A longitudinal study of local and peripheral isotype/subclass antibodies in Dictyocaulus viviparus-infected calves

Although infection with the bovine lungworm, Dictyocaulus viviparus, stimulates high levels of resistance, the mechanisms involved in immunity to this parasite remain poorly understood. In an attempt to address the possible role of antibody in protective immunity, a longitudinal study was carried out in which the levels of both local and peripheral parasite-specific IgG, IgG1, IgG2, IgM and IgA were measured by ELISA. Five calves were infected orally with ten third stage larvae per kilogram on days 0, 65 and 112. Three challenge controls remained uninfected until day 112. Peripheral responses were measured in serum collected weekly and local responses were measured in bronchoalveolar lavage fluid (BALF) collected pre-infection and on two occasions after each infection. After the secondary infection, there were increases in respiratory rates in all the calves, but four of five calves had no first stage larvae (L1) in their faeces, suggesting that the parasites reached the lungs but did not develop to patency. Respiratory rates remained within normal limits after the tertiary infection and there were no parasites in the lungs at postmortem. Locally, in BALF, levels of all the antibody isotypes/subclasses increased after the primary infection, then again after the secondary infection. The highest levels of antibody were detected after the tertiary infection, when the calves were fully immune. In contrast, serum antibody levels increased from day 21 after primary infection and rose again after secondary infection, but thereafter slowly declined, with no increases after tertiary infection. Our findings suggest that the local antibody response was important in the immune response to D. viviparus infections in calves.

Antibodies to Schistosoma japonicum (Asian bloodfluke) paramyosin induced by nucleic acid vaccination

Nucleic acid vaccination by intramuscular or intradermal delivery of DNA plasmids encoding antigenic proteins has been shown to confer protection in experimental animals against viruses and unicellular protozoan parasites. However, this revolutionary approach has not been tested for induction of immunity to multicellular parasites, such as trematode worms. We report here, for the first time, that murine antibodies can be induced by intramuscular injection with plasmid DNA encoding fragments of Schistosoma japonicum paramyosin (Sj97), a 97 kDa molecule and a promising vaccine candidate in schistosomiasis. An additional construct containing the gene encoding full-length glutathione S-transferase (Sj26), another recognised anti-schistosome vaccine target, failed to raise detectable levels of specific antibody.

Studies on the isolation and characterisation of a reaginic antibody in a cat

A reaginic antibody has been demonstrated, by passive cutaneous anaphylaxis (PCA), in the serum of a cat infected with the microfilariae of Brugia pahangi. Recipient cats and pigs were challenged with an extract of Ascaris suum after either a four-hour or a 72-hour period of sensitisation. When the serum was heat treated at 56 degrees C it lost its PCA activity. Gel filtration of the serum revealed a pattern of positive PCA fractions similar to that observed in other species. Attempts to purify the PCA-positive material by Superose gel filtration and ion exchange chromatography by fast protein liquid chromatography (FPLC) were unsuccessful. Affinity chromatography of PCA-positive material by FPLC on protein A demonstrated two bound peaks, the second of which was PCA-positive and eluted as a single peak by ion exchange chromatography. The PCA-positive material from gel filtration did not bind to protein G. The protein A, PCA-positive peak provides a partially purified reaginic antibody for further study.

Potential use of IgG2-ELISA in the diagnosis of chronic elephantiasis and IgG4-ELISA in the follow-up of microfilaraemic patients infected with Brugia malayi

Sera from fifty subjects with different presentations of Brugian filariasis and from common soil-transmitted helminth infections were tested for specific anti-filarial IgG and its subclasses. Anti-filarial IgG, IgG1 and IgG3 showed cross-reactivities with soil-transmitted helminthic infections and no significant differences in optical densities among the various groups of filarial patients. In comparison with other groups of subjects, IgG4-ELISA of sera from microfilaraemic patients and some previously microfilaraemic patients showed a significant increase in optical density readings, while IgG2-ELISA showed elevated optical density readings in sera of patients with chronic elephantiasis. Therefore IgG2-ELISA is potentially useful in the diagnosis of brugian chronic elephantiasis while IgG4-ELISA may be beneficial for follow-up diagnosis of treated microfilaraemic patients.

Examination of murine antibody response to secondary hydatidosis using ELISA and immunoelectrophoresis

Antibody responses in mice with up to 64 weeks of secondary Echinococcus granulosus hydatidosis were examined by ELISA using hydatid protoscolex antigen (Px), Antigen 5 (Ag5) and Antigen B (AgB), and by immunoelectrophoresis (IEP) using sheep hydatid cyst fluid (SHCF). Anti-Px IgG antibodies, evident from 3-5 days post infection (p.i.), increased steadily until 16 weeks and maintained a high level afterwards. Anti-Ag5 IgG antibodies were negligible up to two weeks, but they showed a small increase around 2-3 weeks which was followed by a big increase around 16 weeks p.i. The high level of anti-Ag5 IgG antibodies persisted to the end of experiment. The level of anti-AgB IgG antibodies remained relatively low throughout infection. Anti-Px IgM antibodies appeared in the early period of infection, but became insignificant as the infection proceeded. Specific IgM antibodies to Ag5 and AgB showed two waves of increase, one between 3 days to 4 weeks p.i. and the other between 16 weeks to 46 weeks p.i. The level of IgA antibodies to Ag5 and AgB was low and only a moderate amount of anti-Px IgA antibodies was detected. Generally, a higher level of serum antibodies are associated with a larger number of mature cysts. Serum samples from 5 of 8 mice harbouring hydatid cysts formed 1-3 bands with SHCF in IEP, including Arc 5, but a precipitation are with AgB was not observed. Analysis of hydatid cyst fluid from the infected mice (MHCF) in IEP also failed to demonstrate AgB. Despite the high levels of antihydatid antibodies generated in the infected mice, protoscoleces appeared to be unhindered in their growth to mature cysts.

The profile of IgG and IgG subclasses of onchocerciasis patients

In this study Onchocerca gutturosa was compared with O. volvulus in an ELISA test to detect Onchocerca-specific IgG and IgG subclasses. The test was developed and standardized to detect Onchocerca-specific IgG and IgG subclasses in sera of onchocerciasis patients and endemic controls. Onchocerca volvulus and O. gutturosa crude water-soluble antigens showed no significant difference in detecting onchocerca-specific IgG antibody (T = 1.88, P greater than 0.05). The levels of IgG subclasses varied greatly. IgG4 showed the highest detected mean level (0.84 +/- 0.59) and the other three subclasses showed considerably lower mean levels (IgG1 = 0.27 +/- 0.16, IgG2 = 0.24 +/- 0.17, IgG3 = 0.28 +/- 0.12). The status and score of skin lesions were found to have significant effect on the IgG and IgG subclasses levels (all P less than 0.001). IgG4 showed a positive correlation with the microfilarial (Mf) load (r = 0.21, P less than 0.03). IgG3 levels have a significant negative correlation with the Mf load (r = -0.23, P less than 0.02). The biological significance of these IgG and IgG subclasses in onchocerciasis is discussed.

Early antibody responses in human schistosomiasis

Early diagnosis is important when handling patients with acute schistosomiasis. This state is usually more severe in travellers and tourists than in the immune, resident patients. With increased travelling to areas endemic for schistosomiasis, a tool is needed to solve the problem of differential diagnosis due to the non-specific symptoms of the early stages of the disease. Early appearance of antibodies against excretory/secretory antigens of the intestinal tract in the adult worm was seen in six individuals recently infected with Schistosoma mansoni, using an indirect immunofluorescence technique. The antibodies were of IgM, IgG and IgA classes, and of the IgG1, IgG3 and IgA1 subclasses as detected by ELISA using an antigen preparation of adult worm. On immunoblots, using a freeze-dried adult worm antigen, IgG1 and IgG3 antibodies recognized antigens of 32-35 kD. Antibodies against these antigens could thus be a marker of early infection in previously non exposed visitors to endemic areas.

Evidence for differential induction of helper T cell subsets during Trichinella spiralis infection

The H-2-compatible mouse strains, AKR and B10.BR, exhibit disparate responses to infection with the parasitic nematode Trichinella spiralis. The resistant AKR mice expel intestinal adult worms faster than susceptible B10.BR mice. We tested antibody and lymphokine responses in these strains. With respect to antibody responses, the B10.BR mice had 3- to 10-fold more serum IgE and T. spiralis-specific IgG1 and IgA than AKR mice. The B10.BR mice also had greater numbers of IgG and IgA plaque-forming cells than AKR mice. In contrast, AKR mice produced T. spiralis-specific IgG2a, whereas the B10.BR mice did not. The antibody response kinetics of these strains were similar. We also analyzed lymphokine secretion after restimulating lymphocytes in vitro with T. spiralis Ag. The AKR mesenteric lymph node cells produced more IFN-gamma and less IL-4 than the B10.BR mesenteric lymph node cells. The B10.BR splenocytes produced more IL-4 than the AKR splenocytes, although splenocyte IFN-gamma production was not different. The kinetics of IL-4 production also differed between the two strains. In summary, resistant AKR mice produced more IFN-gamma and T. spiralis-specific IgG2a than susceptible B10.BR mice, which produced more IL-4, IgE, and T. spiralis-specific IgG1. Our results are consistent with differential activation of Th cell subsets in T. spiralis-infected AKR and B10.BR mice.

Differential recognition of two cloned Brugia malayi antigens by antibody class

The humoral and cellular immune response to filarial parasites is complex. Numerous studies have shown that antibodies to a large number of protein and non-protein antigens may be produced over the course of infection and that immune recognition of any given antigen may vary by disease manifestation and by immunoglobulin class. We have used the techniques of molecular cloning to attempt to dissect this complex interaction, and describe here two clones, isolated from an expression library constructed from Brugia malayi genomic DNA, whose products are recognized by distinct immunoglobulin classes. A lambda gt11 fusion protein containing part of the B. malayi myosin tail region is recognized by antibodies of the IgG class from a high percentage of bancroftian filariasis patients. A fusion protein containing a collagen-like sequence is less frequently and weakly recognized under the same experimental conditions, but is almost universally recognized when the developing reagent is specific for IgE. We thus identify specific filarial proteins against which the infected human host responds preferentially with antibodies of a specific immunoglobulin class.

Subclass distribution and IgE responses after treatment in human schistosomiasis

The IgG and IgA subclass distribution of specific antibodies as well as the distribution of total and specific IgE in 15 patients with schistosomiasis was determined in consecutive samples before and after initiation of treatment. An adult worm antigen preparation and a soluble egg antigen preparation were used as antigens in the ELISA assays. After initiation of treatment a rise was noted in certain subclasses and a correlation was found for specific IgG1 and IgG4 serum levels in the egg-excreting patients against adult worm antigen and for specific IgG4 and IgE levels in sera from the eight patients with a chronic disease. They also had a rise of the specific IgA1 titre and six of them also of specific IgA2. Members of eosinophilic granulocytes reached a peak after 2 weeks in seven of the eight patients. The increase of eosinophils was an early event as opposed to the incidence of peak of the determined specific isotypes. The associated rise in IgG1, IgG4 and IgE antibody concentrations and eosinophils may suggest a causal relation possibly induced by common interleukins.

Characterization of the immune mediator of rapid expulsion of Trichinella spiralis in suckling rats

In order to identify and characterize the mediator(s) of rapid expulsion, infant rats were passively immunized against oral challenge with 200 infectious Trichinella spiralis muscle larvae by oral or intraperitoneal (i.p.) administration of secretions or sera from infected rats. Milk whey from infected dams provided a modest level of protection when fed to pups. Immunoglobulins from T. spiralis-infected rat serum protected suckling pups when injected intravenously (i.v.) into lactating dams 2 days prior to pup challenge. Intraperitoneal injection of pups with serum immunoglobulins also enabled them to express rapid expulsion. The protective component of serum was precipitated with 40% (NH4)2SO4 and was not affected by heating to 56 degrees, although antibodies mediating passive cutaneous anaphylaxis were inactivated by both treatments. Oral transfer of biliary immunoglobulins collected from infected rats at various times during a primary infection provided no protection to pups. However, serum immunoglobulins from rats infected for 42 days or longer transferred rapid expulsion to pups. Absorption of protective serum immunoglobulins with subclass-specific reagents revealed that IgG1 played a significant role in protection.

Anti-schistosome monoclonal antibodies of different isotypes-correlation with cytotoxicity

Five monoclonal antibodies specific towards Schistosoma mansoni antigens were prepared by fusion of spleen cells of infected and immunized mouse with the murine myeloma NS-1 cells. Three of the five antibodies belonged to the IgG1 class, one was an IgM and the fifth one was an IgE. The IgE monoclonal antibody designated 54.10, induced antigen-specific degranulation of rat basophilic cell line, a property which served as the basis for the screening assay. Its biological function was demonstrated by a specific macrophage activation that led to killing of schistosomula; no such killing was obtained with anti-schistosome antibodies of other classes or with IgE of different antigenic specificity. The second monoclonal antibody of biological significance was an IgG1, designated 27.21 which is reactive in the immunofluorescence staining of surface antigens on intact schistosomula. All three monoclonal antibodies that belonged to the IgG1 class were effective in mediating killing of schistosomula by complement, with the highest effect exerted by 27.21. It is thus apparent that the 27.21 monoclonal antibody is directed against a densely distributed surface antigen on the schistosomula membrane which is possibly involved in the protective immunity. Preliminary data showed that immunoprecipitation with the 27.21 antibodies results in the isolation of three major protein bands, of 60 kd, 50 kd, 19 kd, respectively.