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Some of the complex antigenic relationships of type I group B streptococci from various clinical sources were defined by means of immunodiffusion, absorption, and precipitin tests. Three predominant types are described: Ia, Ib, and Ii. Methods for preparing antisera for differentiating type I strains are presented.
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Ethanol-precipitated substance (EP) was prepared from culture filtrate of Fonsecaea pedrosoi. EP was separated into two components by passing through a Sephadex G-50 column; the faster passing component was referred to as EP-1, the slower as EP-2. EP-1 and EP-2 were evaluated as an antigen for detecting cutaneous delayed hypersensitivity in patients with chromomycosis. EP-1 elicited positive delayed skin reactions in all of 8 patients with chromomycosis, of which 7 caused by F. pedrosoi and one by Exophiala jeunselmei. Healthy subjects, patients with sporotrichosis and patients with tinea barbae failed to react to EP-1. These results indicate that EP-1 is a useful tool for detecting cutaneous delayed hypersensitivity in patients with chromomycosis caused by F. pedrosoi. It was found that precipitin test using EP-1 as an antigen had little diagnostic value in chromomycosis. EP-2 did not show antigenic activity in both skin and precipitin reactions.
The frequencies of the carriage of yeast pathogens and of serum precipitins to a variety of candida antigens among 254 patients generally tended to increase with the length of the patient's stay in hospital. This trend was observed even though none of the patients investigated showed signs or symptoms of superficial or systemic candidosis. The extent of the general trend varied considerably between subgroups of patients within the general categories of 'surgical' and 'nonsurgical' inpatients. Increases in both frequencies and quantities of yeasts in the mouth were most evident postoperatively among patients who underwent open-heart surgery and among nonsurgical patients who received antibiotics or steroids in hospital. The frequency of precipitins to Candida albicans cytoplasmic antigens in the absence of candidosis rose overall from 11% of 217 sera obtained within 24 hours of admission to 35% of 85 sera obtained five to 11 days after admission or operation. These 'false positive' antibodies were thought to arise after transient yeast overgrowth in the gut at the time of an acute illness or immediately after surgery. The study adds further data to documented examples of 'false positive' candida antibodies and indicates the need for care in the diagnostic interpretation of candida precipitin test results among groups of patients at risk of yeast overgrowth during their hospital stay.
Antisera to streptococcal groups A through G containing 4% polyethylene glycol 6000 were prepared and evaluated. Seventy strains of homologous and heterologous beta- and non-beta-hemolytic streptococci were included in the evaluation. Homologous reactions were determined against extracts prepared by four extraction methods: hot hydrochloric acid (Lancefield) extraction, autoclave extraction, hot formamide extraction, and nitrous acid extraction. Enhancement of the precipitin reaction in the presence of polyethylene glycol 6000 permitted a fourfold dilution of all antisera for use in the capillary precipitin test. At this dilution, the potency of the antisera exceeded requirements established for these reagents.
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A comparison is made of tests for thyroglobulin antibody, using gel diffusion, electroprecipitin, bentonite flocculation, tanned red cell agglutination, and latex slide agglutination techniques on sera from cases of Hashimoto's disease and other thyroid disorders. Any increase in gamma globulin was also noted from the serum electrophoretic pattern. The gel diffusion and electroprecipitin tests are shown to be comparable in their sensitivity, as are the bentonite flocculation and tanned red cell agglutination tests. The flocculation and agglutination tests were oversensitive. The latex slide test in conjunction with the electro-precipitin test is recommended for routine use in the detection of Hashimoto's disease.
The effect of vaccinating cattle and mice on the development of keratoconjunctivitis was studied. Cattle were vaccinated with whole cells, disrupted cells and pili fractions of three strains of Moraxella bovis. Mice were vaccinated with pili fractions of three strains. The resistance of all vaccinated animals was challenged with virulent cultures of M. bovis. In an attempt to correlate the response seen after vaccination and challenge with a pili fraction of M. bovis, vaccinated cattle and mice were grouped on the basis of signs of disease manifested and compared on the basis of serological responses. Serum samples were tested for antibodies by a gel diffusion precipitin test. A greater number of the sera of resistant cattle had antibodies to the homologous pili antigen than those of vaccinated nonresistant cattle. Cattle vaccinated with disrupted cells were not resistant to infectious bovine kerato-conjuctivitis and their sera lacked antibodies against the pili antigens. Vaccinated mice were more resistant to infectious bovine kerato-conjuctivitis and their sera lacked antibodies against the pili antigens. Vaccinated mice were more resistant to challenge exposure by homologous than heterologous cultures. A greater number of the sera of resistant mice had antibodies to pili antigens than nonresistant mice.
Thirty-two type specific cultures used in four typing systems for serologically classifying Pasteurella multocida were compared as originally described for: (1) Little and Lyon's plate agglutination test; (2) Carter's indirect hemagglutination test, hyaluronidase decapsulation test, and acriflavine reaction; (3) Namioka's plate and tube agglutination tests; and (4) Heddleston's gel diffusion precipitin test. In addition, seven cultures from Robert's five passive protection groups were included. When reference cultures were examined by the typing system from which they were described, the results generally correlated with those results published. However, serotypes determined by one typing system generally did not correlate with serotypes determined by another system. Cultures of a single serotype in one system often represented more than one serotype in another system. Results indicated that cultures with one or two serotyping antigens in common may differ in other antigens. Because of the antigenic complexity of P multocida and the nature of the antigens involved in each test, a reliable correlation or equality between serotypes determined by different typing systems could not be made.
A seroepidemiological survey to determine the prevalence of Congo/Crimean haemorrhagic fever virus activity in Iraq was carried out during 1979 and 1980. Sera were collected from 1680 people including contacts of known patients, abattoir workers and animal husbandry workers in various parts of the country. These were tested by complement fixation and agar gel precipitin tests. Among patients' relatives and contacts, 29% had antibodies to Congo/Crimean haemorrhagic fever; 11% of hospital staff, 7% of abattoir workers and 29% of those engaged in animal husbandry had antibodies. Inapparent infections were common in hospital staff caring for patients known to have had the disease. No antibodies were detected in the sera of 151 people who were not believed to have had contact with a known case of the disease.
Candiduria may signify benign saprophytic colonization or true infection of the urinary tract. Histological studies of 64 suspect cases of renal candidiasis, 20 of them positive, suggest that a Candida colony count of 10,000 to 15,000 per ml. or more in a catheterized specimen is a useful cut-off point between infection and colonization. One to 3 Candida per high power field in an uncentrifuged urine specimen equated with a colony count of 10,000 to 15,000 Candida per ml. Colony counts were diagnostically invalid in the presence of an indwelling Foley catheter. Other diagnostic aids included positive serum precipitin tests (83%) and positive blood cultures (47%).
14 enzymatic activities (3 dehydrogenases and 11 hydrolases) were systematically investigated in the extracts of 2 strains of Aspergillus fischeri and 14 strains of A. fumigatus (8 isolated from human or animal lesions named 'pathogenic' strains and 6 strains of saprophytic origin). The enzymic composition of A. fumigatus appeared to be very different from one strain to another but no relationships could be established between enzymic differences and origin of the strains. In addition, the immunoelectrophoretic analysis of these antigenic extracts using rabbits immunsera and sera of patients with pulmonary asperigllosis was performed. The type II chymotrypsic activity, corresponding to C arc, was shown more frequently and gave stronger reaction when antigenic extracts from pathogenic strains were allowed to react with sera of patients. Moreover, when sera of patients revealed a same enzymic activity in a saprophytic strain and a pathogenic strain, the number of precipitin lines was significantly larger with the latter one. Accordingly, antigenic extracts used for precipitin tests had to be preferably prepared from pathogenic strains and tested, for value, against sera of patients with pulmonary aspergillosis.
Schistosomiasis in America with the exception of Brazil, behaves as a chronic mild disease with few clinical manifestations due to low parasite burden. These features restrict the clinical and parasitological diagnosis. The most commonly used stool examination method, Kato-Katz, becomes insensitive when the majority of individuals excrete less than 100 eggs/g of feces. In view that antigen-detecting techniques have not been able to reveal light infections, the antibody detecting assays remain as a very valuable diagnostic tool for epidemiological surveillance. The Venezuelan Schistosomiasis Research Group (CECOICE) has designed a mass chemotherapy strategy based on sero-diagnosis. Since blood sampling is one of the important limiting factors for large seroepidemiological trials we developed a simple capillary technique that successfully overcame most of the limitations of blood drawing. In this sense, ELISA seems to be the most adequate test for epidemiological studies. Soluble egg Schistosoma mansoni antigen (SEA) has been largely used in Venezuela. The sensitivity of ELISA-SEA in our hands is 90%, moreover its specificity reach 92% when populations from non-endemic areas but heavily infected with other intestinal parasites are analyzed. The Schistosomiasis Control Program is currently carrying out the surveillance of endemic areas using ELISA-SEA as the first screening method, followed by the Circumoval Precipitin test for validation assay. The results with these two serological techniques allowed us to defined the criteria of chemotherapy in populations of the endemic areas. On the search of better diagnostic technique, Alkaline Phosphatase Immunoenzyme Assay (APIA) is being evaluated in field surveys.
Methods for the detection of two strains of avian encephalomyelitis virus (AEV) in chick embryo brain cell cultures and chickens were compared. It was found that the agar gel precipitin test (AGPT) and the enzyme-linked immunosorbent assay (ELISA) carried out on the serum of inoculated chickens were more sensitive than either the indirect fluorescent antibody test in cell cultures or the detection of clinical signs in chicks. On the basis of results obtained in this experiment the effects were then determined of routes and time of inoculation of chickens on the detection of AEV. It was found that birds infected at two weeks old produced higher antibody titres than one-day-old birds and the AGPT and ELISA detected comparable levels of antibody in them. It was recommended that the tests to detect the presence of AEV as a contaminant of vaccines be replaced by a serological test carried out on chicks inoculated intramuscularly at two weeks old.
A two-stage radioimmunoassay (RIA) has been developed that identifies type-specific antigens on the surfaces of group B streptococci. In addition to detecting the type-specific carbohydrate antigens Ia, Ib, II, and III, the RIA identified four unique antigens reactive with the Centers for Disease Control's c-protein typing antiserum. Analysis of hot-acid extracts by immunoelectrophoresis confirmed that two of these reactivities corresponded to the reported alpha and beta antigens of the c-protein marker. In addition, the identification of two heretofore unidentified antigens, gamma and delta, by the two-stage RIA is detailed in this report. The assay uses intact bacteria and does not require hot-acid extraction, a procedure thus enabling detection of acid-labile antigens in their native unmodified form. The semiquantitative RIA requires less typing reagent than does precipitin testing and is more objective, reproducible, and rapid. The assay described here could be applied to the detection of any cell surface antigen for which a monospecific antiserum is available.
Two patients were suspected of having extrinsic allergic alveolitis due to exposure to an agent in their home environment. On inspection of their houses, fungal decay was evident in the floorboards, and fungal spores were found deposited on many surfaces. The decay fungus was later identified as Leucogyrophana pinastri. Using an extract of the fruiting bodies and mycelium of this fungus, precipitating antibodies were identified in the sera of both patients. Based on the known exposure by the two patients to these small spores, the absence of a likely alternative allergen, the similarity between these two cases, and the positive precipitin test results, L. pinastri was considered to be the most likely cause of extrinsic allergic alveolitis in our cases.
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Reciprocal cross-protective antigens have been demonstrated between types 3 and 31 cocci, and one-way cross-protective antigens have been demonstrated between types 46 and 51 cocci. The reciprocal cross-protective antigen of types 3 and 31 is distinct from the specific M protein of either type. In the one-way cross relationship, type 46 cocci contain both type 46 and type 51 M proteins and therefore stimulate protective antibodies against both types. Type 51 cultures contain only the homologous M antigen. These relationships were demonstrated by capillary precipitin tests, indirect bactericidal tests, and in agar-gel diffusion patterns. The practical significance of these relationships in the serological typing of group A streptococci is discussed along with their possible role in immunity to streptococcal infections in man.