Cell-mediated and humoral immune responses in capuchin monkeys infected with Schistosoma japonicum or Schistosoma mansoni

Cell-mediated immune responses, assessed by lymphocyte clonal expansion in vitro, as well as humoral responses, assessed by an enzyme-linked immunosorbent assay (ELISA), were evaluated in capuchin monkeys during a 7-month infection with Schistosoma mansoni or with a Japanese or Philippine strain of Schistosoma japonicum. Although mounting a vigorous antibody response against parasite antigens, the S. mansoni-infected monkeys failed to show lymphocyte proliferation in response to stimulation with soluble adult worm antigen or soluble egg antigen derived from S. mansoni. Monkeys infected with S. japonicum responded to parasite antigens obtained from S. japonicum both by antibody production and lymphocyte blastogenesis. Monkeys infected with S. japonicum (Japanese strain) never developed detectable levels of circulating immune complexes (CIC). On the other hand high levels of CIC appeared at 7 months of infection in the monkeys infected with S. mansoni. The CIC levels exhibited negative correlations with intensity of infection. In studies of antigen species specificity, sera from S. mansoni-infected monkeys showed much higher IgG antibody titers to antigens derived from S. mansoni than to S. japonicum-derived antigens. On the other hand, monkeys infected with S. japonicum had comparable IgG antibody titers to antigens of both schistosome species.     

The enzyme-linked immunosorbent assay (ELISA) for malaria. I. The use of in vitro-cultured Plasmodium falciparum as antigen.

Using the Panama II strain of Plasmodium falciparum obtained from continuous in vitro culture as antigen, the micro enzyme-linked immunosorbent assay (ELISA) was used to test serum samples from 50 persons from the southeastern United States and serum specimens collected weekly from four non-immune and nine semi-immune patients infected with P. falciparum. None of the 50 sera from the United States had ELISA antibody titers greater than 1:80. The nine semi-immune patients had rapid ELISA antibody responses (titers greater than 1:2560) following patent parasitemia. ELISA titers remained elevated despite disappearance of patent parasitemia, and declined gradually following curative antimalarial therapy. The ELISA responses observed in the four non-immune patients were more variable, though positive titers appeared rapidly with patent parasitemia. Maximum titers were lower than those observed in semi-immune patients. These results demonstrate that P. falciparum obtained from continuous in vitro culture is an excellent antigen for the micro-ELISA test for malaria. However, further assessments of the ELISA are needed to identify the conditions associated with positive responses.     

Studies of cytomegalovirus infection in renal allograft recipients. II. Serological response to various viral antigens

In a prospective study the antibody response to various cytomegalovirus (CMV) antigens was examined in 28 renal allograft recipients. Both primary and secondary infections were investigated. Antibodies against immediate early (IEA) and early antigens (EA) were studied by anti-complement immunofluorescence; IgM and IgG antibodies to nuclear late antigens were differentiated by enzyme-linked immunosorbent assay (ELISA). The results of the tests were compared with each other and with those of the complement fixation (CF) test. 5/7 susceptible patients (71%) contracted primary infections. Both IgM and IgG antibodies developed and antibodies to IEA and EA appeared somewhat later. The antibodies to IEA and EA remained detectable throughout the observation period. Secondary infections developed in 20/21 (95%) patients. All initially had CMV antibody levels in ELISA and CF. Rising CMV titers of IgG antibodies were taken as a measure of secondary infection. IgM antibodies developed in only 10/20 (50%) patients. The highest titers of CMV IgM antibody levels were lower in secondary than in primary infections. Antibodies to IEA and EA were present prior to transplantation in some patients, but did not develop in all with secondary infections. The antibody titers were lower just after than before the transplantation in some patients. but subsequently increased again. It thus seems as if the humoral immune response to these CMV antigens differs in primary and secondary infections.     

Specific bronchoalveolar lavage IgA antibody in patients with summer-type hypersensitivity pneumonitis induced by Trichosporon cutaneum

Patients with summer-type hypersensitivity pneumonitis induced by Trichosporon cutaneum were studied with respect to specific IgG, IgA, and secretory IgA (S-IgA) antibody activities to T. cutaneum in serum and bronchoalveolar lavage fluid (BALF). A strain of T. cutaneum was isolated from 1 patient's pillow. All serum samples from the family members (2 patients and 2 asymptomatic) contained IgG antibody activity to T. cutaneum, and the titers showed no difference between the patients and asymptomatic family members. On the other hand, IgA and S-IgA antibody activities in serum and BALF were markedly increased only in the patients, and the titers were well correlated with the clinical course. The BALF/serum ratio of specific antibody activity was markedly elevated in IgA and S-IgA antibody activities in striking contrast to that in IgG, suggesting an immune reaction of the respiratory tract. The bronchial challenge test with T. cutaneum antigen was positive in the patients, but not in an asymptomatic family member. These results indicate that measurement of IgA and S-IgA antibody activities in serum and BALF is useful for diagnosis and evaluation of disease activity in summer-type hypersensitivity pneumonitis.     

Microtiter enzyme-linked immunosorbent assay for rubella antibodies in human sera--analysis by parallel line assay method]

Antibodies against rubella virus in human sera were measured by ELISA and antibody titers were calculated by the parallel line assay method. The dose response regression curves of standard sera and test sera containing IgG antibody calculated by the parallel line assay method showed linearity, and were parallel to one another. However, the regression lines of sera positive for IgM antibody against rubella virus were not parallel to one another in the low dilution region, but parallel in the higher dilution region. A good correlation was observed between the rubella IgG antibody titers measured by the hemagglutination-inhibition (HI) test and those calculated by the parallel line assay method. The coefficient of the correlation was 0.781. Time-course studies of IgG or IgM antibody titers against rubella virus in rubella patients or in vaccines with MMR vaccine indicated that the ELISA was more precise and specific method than the HI test. Thus, the parallel line assay method using ELISA is considered to be a more useful method for the detection and quantification of antibodies to rubella than the conventional HI test.     

Antibody response to Schistosoma mansoni adult worm cysteine proteinases in infected individuals

Antigens of the Schistosoma mansoni digestive tract are recognized early in the infective process. Two immunogenic components of the excretory/secretory products are proteolytic enzymes that degrade host hemoglobin in the lumen of the parasite gut. These enzymes, CP1 and CP2, belong to the class of cysteine proteinases. In this study, a preparation containing both proteinases has been used to detect proteinase antibodies in the sera of individuals living in Burundi. Of 133 individuals tested, 92% were excreting schistosome eggs. All patients with documented infections had positive anti-proteinase IgG titers (mean = 1:614), while 82% had positive IgM titers (mean = 1:267). Six weeks following praziquantel treatment, patients were assessed for egg excretion and antibody titer. Anti-proteinase IgG titers were significantly lower (mean = 1:259) than pre-treatment titers. Patients who were infected with S. japonicum or S. haematobium typically showed a cross-reactive IgG response. Patients from non-endemic regions yielded negative titers, and those with non-trematode parasites were negative (79%) or weakly positive. S. mansoni cysteine proteinases may be used for the detection of schistosome infections.     

Serological diagnosis of pulmonary aspergillosis by ELISA

Pulmonary aspergillosis usually develops on the basis of systemic immunosuppression and/or local impairments of respiratory system. Diagnosis of pulmonary aspergillosis has many difficulties. Chest X-ray findings of most cases are complicated with pre-existing changes due to the underlying diseases, and the detection rate of the pathogenic fungi from clinical specimens is unsatisfactorily low. Therefore, immunological or serological diagnosis is urgently required and precipitation-in-gel method has been widely applied. In this report, we compared clinical usefulness of the determination of anti-aspergillus antibodies by ELISA with that of precipitation-in-gel method. ELISA was carried out according to the method previously reported by us (Yamamoto S. et al.: Kekkaku 62: 549, 1987). About two-thirds of 45 healthy adults (control) did not show any detectable IgG anti-aspergillus antibody and mean of IgG anti-aspergillus antibody titer of the control group was 28.97. Patients, who had shown positive culture of fungus or was clinically diagnosed or strongly suspected as pulmonary aspergillosis, showed significantly high anti-aspergillus IgG antibody titer in comparison with the control group. Further, patients who were positive in precipitation-in-gel tests showed significantly higher IgG antibody titers than those who were negative in that test. IgG antibody titer determined by ELISA corresponded with clinical diagnosis much more exactly than the results of precipitation-in-gel test. Further, the results obtained by ELISA were objective and quantitative in comparison with the latter test. We concluded that ELISA was much superior to precipitation-in-gel test and that ELISA IgG antibody titers 2500 or more were confirmative and those between 570 and 2500 were strongly suggestive for the diagnosis of aspergillosis. IgM anti-aspergillus antibody titers were not different among healthy control group and patient groups, and could not be used for the diagnosis.     

Enzyme-linked immunosorbent assay (ELISA) with bacterial sonicate antigen for IgM, IgA, and IgG antibodies to Francisella tularensis: comparison with bacterial agglutination test and ELISA with lipopolysaccharide antigen

An enzyme-linked immunosorbent assay (ELISA) with bacterial sonicate (S) as antigen developed for determining the presence of IgM, IgA, and IgG antibodies to Francisella tularensis was compared with the bacterial agglutination (BA) test and a corresponding ELISA using lipopolysaccharide (LPS) antigen. Of the organisms tested, F tularensis was the only one to cause significant inhibition, indicating the specificity of the S-ELISA. BA test titers correlated significantly with antibody levels in all three immunoglobulin classes and most closely with IgM antibodies (r = 0.83). With some minor exceptions, the S-ELISA and the LPS-ELISA gave identical results, and the correlations between the tests were very close (r = 0.94-0.99). The S-ELISA confirmed the tularemia diagnosis with the first serum specimens from 43% of patients with tularemia vs 17% of the BA test. In addition, no seroconversion was observed by the BA test in 4% of the patients, although large increases were observed in S-ELISA titers.     

The relationship between age,sex, egg-count and specific antibody responses against Schistosoma mansoni antigens in a Ugandan fishing community

In schistosomiasis endemic areas, antibody isotype responses against Schistosoma mansoni antigens vary with host age, sex and duration or intensity of infection, and are associated with susceptibility or resistance to infection. Identifying the quality and quantity of these responses is important to our understanding of the host-parasite relationship; however, the various host and parasite factors have a strong tendency to confound each other. We investigated the relationships and interactions between age, sex, faecal egg-counts and specific antibody isotype (IgA, IgG1, IgG2, IgG3, IgG4, IgE, IgM) responses to S. mansoni worm (SWA) and egg (SEA) antigens, amongst 380 individuals aged 5-59 from a fishing community from Uganda. This community was characterized by high levels of exposure, and high infection intensities, with higher infection intensities in males than in females. Multivariate anova was conducted with interaction terms between the three categorized explanatory variables. Most anti-SWA responses increased with age, whereas anti-SEA responses tended to decline with age, especially after puberty. IgG1-SWA, IgG4-SWA, IgG4-SEA, IgE-SWA responses increased with egg count, whereas IgG2-SEA decreased with egg count. IgG1-SWA, IgG4-SWA, IgE-SWA and IgG4-SEA responses were independently higher in males, whereas IgG2-SEA responses were independently higher in females. The significant effects of sex on isotype responses to adult worm antigens may be partly because of different levels of cumulative exposure. IgG4-SEA and IgG4-SWA were both strongly correlated with egg count. Patterns of IgE-SWA responses were qualitatively different to IgG4 responses, suggesting independent pathways of regulation.     

Antibody response to a purified parasite proteinase (SMw32) in Schistosoma mansoni infected mice

Indirect immunofluorescence of Schistosoma mansoni adult worm sections has revealed that the early immunoglobulin response is directed toward the parasite digestive tract. One of the components of the worm gut is a cysteine proteinase which degrades host hemoglobin ingested by the parasite. In this report the purified proteinase (SMw32) was used in ELISA and immunoblot analyses to study the specific antibody response during the course of an acute infection. We have found high titer IgG antibody in S. mansoni infected, but not uninfected, mice. The anti-proteinase response involves IgM, IgG1, IgG2a, and IgE isotypes. Total IgM and IgG levels increased by week 3 post-infection and remained elevated throughout the study (7 weeks). Increased titers (IgM, IgG) of specific anti-proteinase were also apparent by week 3 post-infection, long before fecal eggs were detectable. Mean anti-proteinase IgG stabilized at high titer by week 5 post-infection, while IgM titers decreased to near background levels. Anti-proteinase IgE was first detectable at week 4 and reached peak titers by weeks 6 and 7. The strong antibody response to the purified SMw32 proteinase is consistent with the early reactivity of S. mansoni infected mice and humans to a 31 kDa component of the worm gut described by others.     

Dinitrochlorobenzene responsivity: difference between patients with severe pulmonary coccidioidomycosis and patients with disseminated coccidioidomycosis.

Immunologic responses in 15 patients with severe pulmonary coccidioidomycosis and in 50 patients with disseminated coccidioidomycosis were measured by determination of complement-fixing (CF) antibody titers to coccidioidin in serum, coccidioidin (1:100) skin tests, and sensitization to dinitrochlorobenzene. Among the patients with desseminated coccidioidomycosis, the nine with CF antibody titers of less than or equal to 1:8 had normal responses to dinitrochlorobenzene, but the 41 with titers of greater than or equal to 1:16 had responses that were significantly lower than those of controls (P less than 0.001). In contrast, all patients with severe pulmonary coccidioidomycosis had CF antibody titers of greater than or equal to 1:16 and had responses to dinitrochlorobenzene that were greater (but not significantly greater) than those of controls. Among subjected with antibody titers of greater than or equal to 1:16, responsiveness to coccidioidin was found in 27% of those with severe pulmonary disease and in 39% of those with disseminated disease. Thus impaired responsivity to dinitrochlorobenzene in coccidioidomycosis is restricted to patients who have disseminated illness and high titers of CF antibody and is separable from lack of responsiveness to coccidioidin.     

Specific antibody profile in human brucellosis.

The results of classic serological tests were compared with those of enzyme-linked immunosorbent assay in studies of immunoglobulins to Brucella in 761 serum samples from 75 patients with brucellosis. Except for five instances involving the IgM ELISA, all serological tests gave positive results at admission. Among the 63 patients without relapse, rates of persistent ELISA positivity (determined by the Kaplan-Meier method) 12 months after therapy were 25% for IgM, 69% for IgA, and 89% for IgG. Among the 12 patients with relapse, a second peak of ELISA IgG and IgA was often detected. The persistence of high serum antibody titers in patients without relapse was due mainly to IgG and was often associated with high titers at admission or with the presence of focal disease. Overall, serological changes were better detected by ELISA than by classic serological tests. While a second peak of ELISA IgG and IgA is a good marker of relapse, the persistence of high titers of IgG by itself is not a good predictor of chronic infection.     

Antibody response to a polysaccharide antigen present in the schistosome gut. II. Modulation of antibody response.

Specific IgM and IgG antibody to a polysaccharide present in the epithelial cells of the gut of adult schistosomes was measured in four groups of infected patients: I) patients with documented acute schistosomiasis; II) Americans exposed to schistosomiasis within the preceding 0--4 years; III) chronically and heavily infected patients, mostly from Puerto Rico, without hepatomegaly or hepatosplenomegaly; and IV) heavily infected Brazilian children with hepatic or hepatosplenic schistosomiasis. Specific IgM and IgG titers were both highest in the acute Group I patients and lowest in the chronically infected Groups III and IV. Total IgG and IgM levels were compared to specific antibody titers. Immunoglobulin levels tended to follow specific antibody titers except in the chronically infected Groups III and IV in which total IgG rose to high levels. The decrease in specific antigen titers over the course of time occurred despite continued antigenic stimulation and suggests a modulation of the humoral response. The mechanism remains obscure.     

Specificity of antibodies and tuberculin response after occupational exposure to tuberculosis.

Specific antibody levels and delayed-type hypersensitivity skin responses to antigens of Mycobacterium tuberculosis in 39 hospital staff who were heavily exposed to tuberculosis (TB) were compared with those in 36 factory employees from Indonesia. Antibody levels to the TB68 epitope of the 14-kDa antigen were significantly greater, while titers to the TB23 (19-kDa) and TB72 (38-kDa) epitopes and lipoarabinomannan (LAM) were lower in exposed than in nonexposed subjects (all P less than .02). The intensity of tuberculin responses correlated positively with anti-LAM and negatively with anti-19-kDa antibody levels. Possible reasons for the selective humoral response of chronically exposed healthy subjects to the 14-kDa antigen, but not to other antigens immunogenic in patients with tuberculosis, are discussed.     

Specific isotype immune response in the diagnosis of human schistosomiasis pathology?

Since the few indirect markers available for assessing the development and the stage of intestinal schistosomiasis morbidity are weakly specific, endoscopy is still the only method able to detect severe forms of pathology. Therefore, we evaluated the isotype antibody response to the current schistosome antigen preparation (soluble egg antigens [SEA]) in 142 Senegalese patients infected with Schistosoma mansoni. They were stratified into three different stages of pathology according to ultrasonographic, endoscopic, and clinical parameters (stage 1 = no detectable pathology; stage 2 = moderate morbidity; stage 3 = severe forms of pathology). Only median specific IgG4, IgE, and IgA responses changed according to the stage of pathology. The IgA level was significantly higher in stages 2 and 3 compared with stage 1, and the IgE level was higher in stage 3 compared with stage 1. A high specific IgG4 level was observed only in stage 3 and was significantly different compared with stage 2. We show an association between the variability of the specific response to SEA and the degree of morbidity, and demonstrate that IgA and IgG4 responses could be combined markers to easily discriminate the different stages of pathology due to infection with S. mansoni.     

The effect of prophylaxis with chloroquine and proguanil on delayed-type hypersensitivity and antibody production following vaccination with diphtheria, tetanus, polio, and pneumococcal vaccines

In vitro studies have shown that anti-malarial drugs suppress immunity. In this study, the effects of chloroquine and proguanil (Paludrine) on the cellular and humoral immune system were measured by two in vivo methods: 1) cell-mediated immunity (delayed cutaneous hypersensitivity) i.e., skin tests with seven delayed-type common antigens (Multitest) and 2) humoral immunity by measurement of specific antibody response to vaccination. Sixty healthy young individuals were randomized into four groups and given 1) no treatment (controls), 2) chloroquine diphosphate (500 mg/week), 3) chloroquine diphosphate (1,000 mg/week), or 4) proguanil hydrochloride (200 mg/day) for six weeks. Skin testing was performed on days 0 and 28. Vaccinations with diphtheria, tetanus, polio, and pneumococcal polysaccharide antigen vaccines were performed on day 28, and the presence of specific antibodies was determined on days 0, 28, and 42. The skin tests induced a significant increase in skin reactive areas from day 0 to day 28 in all groups. Furthermore, the skin test induced an increase in the level of specific IgG for diphtheria and tetanus, but had no effect on antibodies to antigens not included in the skin test. The results showed that there were no significant differences among the four groups regarding skin test areas and increases in antibody titers following vaccination. Therefore, it is concluded that in healthy persons, six weeks intake of chloroquine, even in double doses, or proguanil in chemoprophylactic dosages, does not induce any detectable suppression of delayed-type hypersensitivity or vaccination responses to diphtheria, tetanus, polio, or pneumococcal polysaccharide antigens.     

Food-specific serum IgG4 and IgE titers to common food antigens in irritable bowel syndrome

INTRODUCTION: Food hypersensitivity is a common perception among irritable bowel syndrome (IBS) patients. Data from dietary elimination and food challenge studies support an etiopathological role of diet in IBS, but there are no well-established tests to identify food hypersensitivity. AIM: To compare IgG4 and IgE titers to common food antigens in IBS and controls. METHOD: One hundred and eight IBS [52 diarrhea-predominant (D-IBS); 32 constipation-predominant (C-IBS); 24 alternating (Alt-IBS)], and 43 controls were included in the study. IgG4 and IgE titers and skin prick testing (SPT) to 16 common foods including milk, eggs, cheese, wheat, rice, potatoes, chicken, beef, pork, lamb, fish, shrimps, soya bean, yeast, tomatoes, and peanuts were measured. RESULTS: IBS had significantly higher IgG4 titers (mug/L) to wheat (395 IQR +/- 1,011 vs 0 IQR +/- 285, p < 0.001), beef (1,079 IQR +/- 930 vs 617 IQR +/- 435, p < 0.001), pork (481 IQR +/- 379 vs 258 IQR +/- 496, p < 0.001), and lamb (241 IQR +/- 460 vs 167 IQR +/- 232, p= 0.009) compared to controls. These differences were maintained across all three subgroups. The antibody titers to potatoes, rice, fish, chicken, yeast, tomato, and shrimps were not significantly different. No significant difference in IgE titers was observed between IBS and controls. SPT was positive for only a single antigen in 5 of 56 patients tested with the same panel of foods. No correlation was seen between the pattern of elevated IgG4 antibody titers and patients' symptoms. CONCLUSION: Serum IgG4 antibodies to common foods like wheat, beef, pork, and lamb are elevated in IBS patients. In keeping with the observation in other atopic conditions, this finding suggests the possibility of a similar pathophysiological role for IgG4 antibodies in IBS.     

Influence of human T-cell lymphocytotropic virus type 1 infection on serologic and skin tests for strongyloidiasis.

The aim of this study was to determine whether human T-cell lymphocytotropic virus type 1 (HTLV-1) infection may affect the levels of parasite-specific immunoglobulin (Ig) G and IgE and the positivity of the skin test for strongyloidiasis. Participants included 67 patients with strongyloidiasis (40 without HTLV-1 infection and 27 coinfected with HTLV-1). We determined IgG and IgE levels by enzyme-linked immunosorbent assay, and the immediate hypersensitivity skin test was performed with the metabolic Strongyloides stercoralis antigen. Specific IgE levels and the size of skin reactions in patients without HTLV-1 were higher (P < 0.01) than those observed in patients coinfected with HTLV-1. Additionally, 89% of patients without HTLV-1 had specific IgE and 92.5% had positive skin tests; however, these values were significantly reduced (P < 0.01) in patients coinfected with HTLV-1 (44% and 59%, respectively). These data show that HTLV-1 infection decreases the sensitivity of detection of S. stercoralis-specific IgE, the size of the immediate hypersensitivity reaction, and the sensitivity of these tests in the diagnosis of strongyloidiasis.     

Antibody response to a polysaccharide antigen present in the schistosome gut. I. Sensitivity and specificity.

By using paraffin sections of adult schistosomes fixed in Rossman's fixative, specific human IgM and IgG antibodies to a polysaccharide present in the epithelial cells of the schistosome were measured by using indirect immunofluorescent techniques. Of the 49 patients, mostly infected with S. mansoni but a few infected with S. haematobium or S. japonicum, all had antibody present at a 1:8 dilution of serum. Specific IgM antibody was more sensitive than IgG, yielding 100% and 86% positivity respectively. The false positive rate was 3% in a panel of sera obtained from patients most of whom were infected with other parasites. Antibodies were detected by the 3rd week in experimentally infected animals. Unisexual infections also induced antibody production. As a diagnostic test, the measurement of antibody to the polysaccharide is an easily performed reliable test with high sensitivity and specificity.     

Enzyme-linked immunosorbent assay for the diagnosis of clinical and subclinical melioidosis

An enzyme-linked immunosorbent assay (ELISA) for the detection of specific IgG and IgM antibody to Pseudomonas pseudomallei was developed. The IgG-ELISA was compared with the indirect fluorescence assay for IgG antibody (IgG-IFA) and the indirect hemagglutination (IHA) test in studies with serum specimens from persons from endemic areas for melioidosis and from persons from nonendemic areas of Australia. The sensitivity and specificity of the IgG-ELISA were 90% and 99%, respectively, comparable to those obtained with the IgG-IFA. The IgG-ELISA was more sensitive than the IHA test (74%) and was more suitable than the IgG-IFA as a serologic screening test for melioidosis. The IgM-ELISA was compared with the IgM-IFA as a marker of disease stage in patients with melioidosis. There was good diagnostic agreement between the tests; 92% of patients with active disease gave IgM-ELISA titers greater than or equal to 1:5,120 and 93% of patients with subclinical melioidosis had IgM-ELISA titers less than or equal to 1:1,280. Of the overlap group of patients with a borderline IgM-ELISA titer of 1:2,560, approximately 33% were clinical cases. An uncommon disease stage consisting of a self-limited, short-term, flu-like, pyrexial illness accompanied by elevated serum IgM-ELISA titers (greater than or equal to 1:5,120) was seen in a small number of patients residing in endemic Australia.