IgG subclass distribution of antibodies against S. aureus teichoic acid and alpha-toxin in normal and immunodeficient donors

IgM, IgG, IgA and IgE class and IgG and IgA subclass levels were determined in 18 IgG2 deficient and six IgG3 deficient donors. IgG2 deficiency was associated with concomitant IgG4, IgA (in particular IgA2) and IgE deficiency. This pattern is compatible with a regulation defect of the downstream switch in the heavy chain locus on chromosome 14. IgG3 subclass deficiency was not associated with further deficiencies. Specific anti-teichoic acid antibodies were lacking in most IgG2 deficient donors supporting the notion that anti-teichoic acid antibodies are normally of this subclass. This was also confirmed in a subclass-specific ELISA using sera from normal donors although substantial amounts of specific IgG1 antibodies were also noted. Two IgG2 deficient donors had normal IgG titres (IgG1 in the subclass specific ELISA) and the lack of IgG1 anti-teichoic acid antibodies in most IgG2 deficient donors may suggest a lack of maturation of the appropriate idiotype. IgG antibodies to alpha-toxin, a pure protein, were within the lower normal range in a large proportion of IgG2 deficient donors but largely normal in the IgG3 deficient donors.

Diagnosis of whooping cough--a comparison of culture, immunofluorescence and serology with ELISA

Three methods for diagnosis of whooping cough--culture, immunofluorescence (IF) technique on nasopharyngeal secretion and serology with ELISA--were compared. 52 patients with symptoms of upper respiratory tract infection, which could not exclude pertussis as a differential diagnosis, were investigated. Pertussis infection was confirmed in 30 patients. Of these 16 (53%) were found by culture, 19 (63%) by IF and 28 (93%) by serology. It is concluded that IF analysis of nasopharyngeal secretion is a valuable tool for rapid diagnosis of whooping cough with a sensitivity similar to that of culture. Serodiagnosis with ELISA added a significant number of positive patients in which culture and IF were negative.

Enzyme-linked immunosorbent assay (ELISA) for antibodies to Clostridium difficile toxins in patients with pseudomembranous colitis and antibiotic-associated diarrhoea

Enzyme-linked immunosorbent assay (ELISA) was established with purified toxins from Clostridium difficile as antigen to measure antibody response in patients with pseudomembranous colitis (PMC) and prolonged antibiotic-associated diarrhoea (AAD). Positive ELISA titres were defined in a control population. Antibodies of IgG class against toxin B were demonstrated in 6/88 (7%) control sera and in 31/61 (51%) sera from 11/19 (58%) patients. Antibodies of IgA class were found in one patient while antibodies of IgM class were not demonstrated. ELISA antibodies against toxin A were not demonstrated. For comparison a neutralization test was performed and neutralizing antibodies to toxin B but not to toxin A were demonstrated in 10/61 (16%) sera from 4/19 (21%) patients and in none of the controls. ELISA was found to be a more sensitive assay than neutralization. ELISA antibodies were detected from the third week of the disease while neutralizing antibodies appeared after 5 weeks. Lack of an antibody response in ELISA seemed to correlate to a more severe colitis.

Enzyme-linked immunosorbent assay for antibodies against teichoic acid in patients with staphylococcal infections

A highly purified teichoic acid preparation was used in an enzyme-linked immunosorbent assay to measure the specific immunoglobulin G (IgG) and IgM response in staphylococcal disease. Antibody determination in a normal population, showing a difference of up to 20-fold in the mean IgG titers between the youngest children and adults, was used to establish age-correlated upper normal values. IgM antibodies were found to be of little diagnostic value since their response was often low or absent. Increased IgG titers were found in 24 of 27 (89%) patients with endocarditis, in 11 of 14 (79%) with complicated septicemia, and in 10 of 20 (50%) with uncomplicated septicemia with serum samples drawn between days 7 and 30 of disease. With paired samples, the numbers of patients with increased IgG titers were 17 of 17, 3 of 4, and 6 of 7, respectively, in the same patient groups. Increased IgG titers were less often demonstrated in patients with chronic osteomyelitis (7 of 22). The enzyme-linked immunosorbent assay for teichoic acid antibodies was found to be a sensitive and specific method for diagnosing staphylococcal endocarditis and septicemia. For optimal results, both the substantial age-correlated variation in normal titers and the importance of adequately spaced samples should be considered.

The role of antibodies against alpha-toxin and teichoic acid in the diagnosis of staphylococcal infections

An enzyme-linked immunosorbent assay (ELISA) was used with purified alpha-toxin and teichoic acid preparations to measure the IgG and IgM response in Staphylococcus aureus infections. After determining antibodies in a normal population, cut-off levels were set for all age groups. ELISA with alpha-toxin was more sensitive than the antistaphylolysin neutralization test (ASTA). Determining IgM antibodies with the two antigens was found to be of limited diagnostic value. Positive IgG titers against alpha-toxin were found in 21 of 27 patients (78%) with endocarditis, 11 of 14 (79%) with complicated septicemia, eight of 20 (40%) with uncomplicated septicemia and in 12 of 22 (54%) with chronic osteomyelitis. The IgG responses to teichoic acid and alpha-toxin were somewhat different when measured by ELISA, and the parallel performance of the two assays resulted in improved serological diagnostics. The number of positive patients increased to 89%, 86%, 65% and 64%, respectively, in the four groups with a diagnostic specificity of 93%. In septicemic staphylococcal infections, the diagnosis could be established in all patients (28 of 28) with adequately spaced paired samples.

Serological diagnosis of deep Staphylococcus aureus infections by enzyme-linked immunosorbent assay (ELISA) for staphylococcal hemolysins and teichoic acid

An enzyme-linked immunosorbent assay (ELISA) was used with a purified alpha-toxin preparation to measure the serum IgG, IgM and IgA response in staphylococcal septicaemia and endocarditis. ELISA for IgG antibodies against alpha-toxin was found to be more sensitive than the neutralization test (ASTA). IgM and IgA antibody determination was found to be of limited diagnostic value. A correlation between IgG antibodies to alpha-toxin and purified beta-toxin was found in ELISA, although antibody determination to beta-toxin was a less sensitive diagnostic method. The highest diagnostic sensitivity in deep staphylococcal infections was obtained by parallel performance of ELISA to alpha-toxin and purified teichoic acid. By this approach, 32/35 (91%) patients with endocarditis, 12/14 (86%) with complicated septicaemia and 15/22 (68%) with uncomplicated septicaemia showed increased titres in samples drawn between days 7-30 of disease. Diagnostic sensitivity was further increased to 31/32 (97%) positive patients, when paired or multiple samples from patients with septicaemic staphylococcal disease were analysed.

Serologic diagnosis of whooping cough by an enzyme-linked immunosorbent assay using fimbrial hemagglutinin as antigen

Diagnosis of whooping cough by an enzyme-linked immunosorbent assay (ELISA) that measures serum IgG, IgM, and IgA antibody to the fimbrial hemagglutinin of Bordetella pertussis was compared to isolation from nasopharyngeal swabs in a prospective study. Of 77 patients with upper respiratory tract infections of unknown etiology in which B. pertussis infection could not be excluded on clinical grounds, 26 were culture-positive, including one for Bordetella parapertussis. All 26 patients were positive by ELISA except one asymptomatic erythromycin-treated patient (ELISA sensitivity, 96%). Among culture-negative patients, 24 additional patients were positive by ELISA. Thus, only about one half of the patients with whooping cough were identified by culture under optimal conditions. Positive titers of IgM antibody and/or high titers of IgG antibody in the first serum sample, allowing for a rapid diagnosis, were found only in 26 (53%) of 49 serologically positive patients. By combining culture testing with serology, rapid diagnosis was obtained in 41 (82%) of 50 patients.

Purification and characterisation of a fimbrial haemagglutinin from Bordetella pertussis for use in an enzyme-linked immunosorbent assay

The fimbrial haemagglutinin (F-HA) of Bordetella pertussis grown on solid medium was extracted with 1M sodium acetate for 72 h at 20 degree C, and partially purified by Sephacryl S-300 gel chromatography. A pooled fraction with fimbrial haemmagglutinating activity was shown to contain fimbriae haemagglutinating activity was shown to contain fimbriae of the expected morphology by electron microscopy. Chemical and biological assays showed that the F-HA fraction contained some heat-labile agglutinogen and lipopolysaccharide but no measureable lymphocytosis-promoting factor or heat-labile toxin. The F-HA fraction used as antigen in an enzyme-linked immunosorbent assay (ELISA) permitted the detection of antibodies in convalescent serum from a patient with whooping cough. The impurities, heat-labile agglutinogens and lipopolysaccharide, did not contribute to the ELISA activity. The method for preparation of the F-HA antigen is simple, reproducible and gives a high yield.

Detection of antibodies in human serum against the fimbrial haemagglutinin of Bordetella pertussis by enzyme-linked immunosorbent assay

Antibody responses in human sera against Bordetella pertussis during natural infection were investigated by a microplate enzyme-linked immunosorbent assay (ELISA) with a purified fimbrial haemagglutinin preparation as antigen. Significant rises of specific IgG, IgM and IgA were demonstrated in paired sera. A secondary type of antibody response was found in most children and adults. In children, the type of response correlated with previous vaccination status; there was a primary response in unvaccinated children. A survey of antibodies in the general population showed low IgG titres in a small proportion of sera from the youngest healthy children. The titres and the number of individuals with measureable antibodies increased with age. In a limited study of the effect of vaccination, significant rises of titres were demonstrated after vaccination. The ELISA test was specific for antibodies against B. pertussis except that the test also seemed to measure antibody to B. parapertussis. A comparison between ELISA and the complement-fixation test showed a good correlation between the tests only in sera from children 1-12 years old.

Antibody response to cytomegalovirus: a comparison between adult patients with neurological disease and uncomplicated infection

Cytomegalovirus (CMV) infection in adults can cause neurological diseases such as the Guillain--Barré syndrome (GBS) and myelitis. The mechanism leading to the development of neurological damage is, however, still unknown. We have investigated the possibility that an abnormal humoral immune response, either weak or hyperactive, could be the cause. The antibody response of four patients with a primary CMV followed by neurological symptoms was compared to that of four age-matched controls with an uncomplicated infection. IgG and IgM antibodies to CMV early antigens (EA), late antigens (LA), and IgG antibodies to CMV immediate early antigens (IEA) were measured in consecutive serum samples. Comparison of titers indicated a longer time lapse between the onset of CMV infection and the development of symptoms in the group with neurological disease. We found no conclusive evidence of an abnormal humoral immune response to CMV in the patients with neurological disease compared to the patients with an uncomplicated infection.

Early diagnosis of tick-borne encephalitis (TBE) by demonstration of specific IgM antibodies

The demonstration of specific IgM antibodies after separation of immunoglobulins was used for the early diagnosis of tick-borne encephalitis (TBE). The separation was done by sucrose-gradient density ultracentrifugation and IgM antibodies were demonstrated with the hemagglutination-inhibition (HI) test. IgM antibodies were found in 9/11 sera taken within 3 days after onset of clinical symptoms and in all sera (37/37) taken 4--15 days after onset of the disease. Most sera (22/24) were still IgM positive 3--6 weeks after onset of the disease. After this period of time IgM antibodies could no longer be defected. The demonstration of IgM antibodies also proved valuable in confirming the diagnosis in several cases where no antibody rise was found neither by the complement-fixation (cf), nor by the HI test.

The polyclonal B cell activator dextran-sulphate induces formation of colony stimulating activity

The effect of dextran-sulphate (DS), a polyclonal activator known to stimulate immature murine B-cells, was assayed in a culture system allowing the growth of myeloid cells. It was known that DS induced the production of a myeloid colony stimulating factor (CSF) by cells from both spleen and bone marrow. Nylonwool purified mouse spleen cells, enriched for T cells, showed a dimished CSF production in response to DS, while CSF production in response to Con A was increased. Furthermore, DS induced CSF in both spleen and bone marrow cells from nude mice. Removal of macrophages did not affect CSF production. The CSF induced was non-dialysable and no small molecular weight or lipoprotein inhibitors could be demonstrated. The results suggest that DS activates cells other than T cells or macrophages (possibly B cells or null cells) to produce a myeloid stem cell stimulating substance. These results indicate that interactions between lymphoid and myeloid cells can take place during differentiation.

Perinatal cytomegalovirus infection in man

In a prospective study of 148 children from urbanized southern Finland 3 were found to be congenitally and 48 perinatally infected with cytomegalovirus (CMV), while 6 developed "late" infection during the first year of life. During pregnancy and the first year after delivery 23 of the mothers had no CMV antibodies; none of the children of these seronegative mothers developed any type of CMV infection. Fresh blood exchange transfusions did not increase the risk of CMV infection. The data support the hypothesis that the mother is the source of perinatal CMV infection. Children with a low birthweight not due to prematurity, and first children seem to run a greater risk of acquiring perinatal CMV infection. If the child is breast fed up to the age of 2 months the risk seems to be increased. Perinatal CMV infection gave rise to no symptoms or signs and had no effect on growth or on motor and psychosocial development during the first year of life.