Evaluation of a Microtiter Latex Agglutination Test for Histoplasmosis

Experiments were designed to evaluate a Microtiter latex agglutination (Micro-LA) test, as a serological aid in the diagnosis of histoplasmosis, and to compare this test with the conventional microtiter-complement fixation (CF) test for histoplasmosis. Sera tested were from cases of acute and chronic pulmonary and disseminated histoplasmosis, as well as from individuals not having histoplasmosis. Ninety-seven percent of the cases of acute pulmonary histoplasmosis had positive Micro-LA tests, whereas 91% had positive CF tests. Ninety-six percent of the patients having chronic pulmonary histoplasmosis showed positive Micro-LA tests and 91% had positive CF tests. In contrast, 64% of the cases of disseminated histoplasmosis had positive Micro-LA tests, whereas 82% had positive CF tests. None of these differences was statistically significant. Although there were no significant differences in complement fixing and agglutinating antibody cross-reactivity with Blastomyces antigens, more patients demonstrated CF titers than Micro-LA titers. Sera from patients with acute and chronic histoplasmosis showed higher Micro-LA titers than CF titers, whereas sera from cases of disseminated histoplasmosis showed higher CF titers. Histoplasmin skin testing has less of a boosting effect on agglutinating antibodies than on CF antibodies to histoplasmin. Anticomplementary sera can be used in the Micro-LA test. This test is simple to perform, and results can be obtained in 2 to 4 hr.     

Evaluation of purified H and M antigens of histoplasmin as reagents in the complement fixation test.

Complement-fixation (CF) tests were performed with purified H and M antigens, histoplasmin, and Histoplasma capsulatum whole cell yeast phase antigen using sera of 126 patients with proven or suspected histoplasmosis. Specific titers for either H or for M antibody were obtained with the individual purified antigens; the highest titers were comparable to those obtained with histoplasmin. However, in sera containing only anti-M antibody, the titers obtained with the purified M antigen were 2 to 16 times those obtained with the histoplasmin or yeast phase antigens. The CF test for either H or M antibody was 4 to 32 times as reactive as the agar-gel microimmunodiffusion test; in general precipitin lines were obtained with either H or M antigens from sera with CF titers greater than or equal to 8. With sera containing H antibody, there was an excellent correlation between the CF titers obtained with purified M antigen and histoplasmin. The correlations of CF titers with H antigen and either histoplasmin or yeast phase antigen were very low.     

Diagnostic usefulness of the intradermal test with histoplamin in non-endemic areas of histoplasmosis

The histoplasmosis in Spain is an imported disease presenting in most of case diagnostic difficulties. In this paper, the intradermal skin test with Histoplasma capsulatum antigen as diagnostic method in immunocompetent patients with clinical and radiological signs compatible with histoplasmosis after being visited Central and South American endemic counties, in which this mycosis is endemic. Nine Spanish patients coming from different countries of Latin America with fever and acute respiratory symptoms compatible with histoplasmosis were studied. Other nine accompanying subjects and five controls were also evaluated. Patients underwent mycological cultures and and serological tests for H. capsulatum. Intradermal test with 1% histoplasmine were done in all patients. Serology and skin tests tests were also performed in accompanying people. Intradermal were done in healthy controls. Skin test with histoplasmine were positive in seven of the nine patients. Six of these showed precipitating antibodies against the same antigen. H. capsulatum was only isolated from bone marrow biopsy samples in one patient. The seven patients were given itraconazole by oral route and all symptoms improved after 2 and 4 weeks. In five accompanying subjects the skin test were also positive so that a subclinical histoplasmosis was diagnosed. In the remaining patients and healthy accompanying subjects histoplasmosis infection was excluded. In non endemic geographical areas of histoplasmosis intradermal skin test with histoplasmin when used in immunocompetent individuals is an easy and reliable method for the diagnosis of this mycosis as well as for epidemiological studies.     

Additional studies of histoplasmin formation

Summary Culture filtrates of 20 strains ofHistoplasma capsulatum were studied to determine the effect of certain growth conditions on histoplasmin formation. The presence of histoplasmin was denoted by an antigenic titer of 1:4 or higher with the complement fixation test.The data indicated that, in addition to verifying that the strain used affected histoplasmin formation, the morphological condition of the inoculum was extremely important. It was found that most strains which converted readily to the yeast phase at 37° C produced histoplasmin poorly. Tests with different volumes of media also showed that 500 ml volumes of culture media produced histoplasmin with higher titers than 3 liter volumes when cultured at 25° C for six months.Some additional histoplasmin could be liberated by sonification of the mycelial pad from culture filtrates which contained histoplasmin. A few strains produced high titer histoplasmin by the shake method if incubated for three months, but they had low titers after only six weeks.Complement fixation tests with sera from proven cases of histoplasmosis indicated that histoplasmin from a single strain ofH. capsulatum can give identical results with those obtained with histoplasmin from a pool ofH. capsulatum strains if H and M antigen components are present.     

Value and Interpretation of Serological Tests for the Diagnosis of Cryptococcosis

MAXIMAL SEROLOGICAL DIAGNOSIS OF CRYPTOCOCCOSIS MAY BE ACCOMPLISHED THROUGH THE CONCURRENT USE OF THREE TESTS: the latex agglutination (LA) test for cryptococcal antigen, and the indirect fluorescent antibody (IFA) and tube agglutination (TA) tests for Cryptococcus neoformans antibodies. These tests were applied to 141 serum and cerebral spinal fluid specimens from 66 culturally proven cases of cryptococcosis and to 42 sera from normal subjects and from patients with other systemic mycotic diseases. The LA test was sensitive and completely specific; of the sera from proven cases, 55% were positive. With the TA test, 37% of the specimens were positive and the test was highly specific. With the IFA test, 38% of the specimens were positive and the test appears to be the least specific of the three. Cross-reactions were most evident with blastomycosis and histoplasmosis case sera. When the three tests were used concurrently, 87% of the cryptococcosis case specimens were positive and permitted a presumptive diagnosis of C. neoformans infections in 61 (92%) of the 66 patients whose specimens were examined.     

Latex agglutination test for diagnosing pneumococcal pneumonia in children in developing countries.

OBJECTIVE--To prepare and assess the sensitivity and specificity of a latex agglutination test specific for the serotype of antigen in diagnosing pneumococcal pneumonia in Gambian children. DESIGN--Comparison of agglutination test specific for serotype with culture of blood and lung aspirates, countercurrent immunoelectrophoresis, and commercial latex agglutination tests in diagnosing pneumococcal pneumonia. Cross reaction studies and investigation of 102 control children to determine specificity of agglutination test specific for serotype. SETTING--General medical ward of Medical Research Council laboratories, The Gambia. PATIENTS--101 Gambian children aged between 2 months and 10 years admitted with severe pneumonia. INTERVENTIONS--Serum samples were boiled and treated with edetic acid, and urine samples were boiled and concentrated 25 times before testing. END POINT--A latex agglutination test specific for the serotype of pneumococcal antigen that is sensitive and highly specific for detecting pneumococcus in the urine of patients with pneumococcal pneumonia. MEASUREMENTS AND MAIN RESULTS--Concentrated urine samples from 16 of the 21 children (76%) with pneumococcal pneumonia established by results of culture of blood or lung aspirates gave a positive result with the agglutination test specific for serotype, whereas only four of the 102 urine samples obtained from control children without pneumonia gave positive results. The serotypes of antigens detected in the urine of children with pneumococcal pneumonia and the serotypes of pneumococci isolated from cultures of blood or lung aspirates were the same in all cases. CONCLUSIONS--When performed on urine samples the agglutination test specific for serotype has a high specificity and is more sensitive than culture of blood or lung aspirates, commercial agglutination tests, or countercurrent immunoelectrophoresis in identifying pneumococcal pneumonia. It is easy to use and should be especially useful in communities with limited laboratory facilities.     

A preliminary note on inter-reaction of skin test sensitivity between Histoplasmin and Chrysosporin in experimental animals

Summary Species ofChrysosporium have been isolated from soil in Iran. Guinea pigs inoculated withChrysosporium keratinophilum gave a positive skin test to histoplasmin and vice versa. This would suggest thatChrysosporium species might be reponsible for positive skin tests to histoplasmin in areas known not to be endemic for histoplasmosis.     

The preparation of an IgG diagnostic agent based on stained polyacrolein latexes for use in the latex agglutination reaction

IgG diagnosticum for measuring the concentration of 131I-labeled IgG antibodies to enteric antigen beta 1MA by the latex agglutination inhibition (LAI) test has been prepared on the basis of polyacrolein latexes. A method for the titration of anti-IgG antibodies with the use of the above diagnosticum has been developed, based on the late, agglutination (LA) test. The optimum conditions for the microtitration variant of the LA and LAI tests have been defined. High sensitivity, specificity and simplicity of analysis with the use of latex IgG diagnosticum have been demonstrated. The newly developed methods have been successfully used in laboratory trials of a new diagnostic radiopharmaceuticals for the assay of 131I-labeled antibodies in this preparation and for the detection of side effects of immunization on the recipients.     

THE DISTRIBUTION OF COCCIDIOIDOMYCOSIS IN SOUTHERN CALIFORNIA

In coccidioidin skin test surveys among persons of high school age in Saugus, Canoga Park, Banning and Palm Springs areas the average incidence of positive reaction was 15 per cent. Although considerably less than the 68 per cent incidence reported among high school students of Kern County, it is high enough to indicate pockets of relatively high endemicity in Southern California below the San Joaquin Valley.Histoplasmin tests were performed on most of the persons tested with coccidioidin in this survey. The over-all incidence of positive reaction in the group was 7.6 per cent. Most of the subjects with positive reaction to histoplasmin gave a history of having previously lived in some area in the central United States where histoplasmosis is known to be endemic.A few subjects who had positive reaction to coccidioidin tests and who had lived in areas known to be endemic for coccidioidomycosis but not for histoplasmosis, also had positive reaction to histoplasmin. However, the induration produced was always smaller than that caused by the coccidioidin reaction, and there was minimal confusion in interpreting the tests.     

Estudio comparativo de las reacciones serologicas cuantitativas con un antigeno metabolico de Aspergillus fumigatus

Summary The following quantitative serologic reactions: agar-gel immunodiffusion, complement-fixation, opposite electrophoresis and latex particle agglutination tests have been performed in 38 sera from mycologically proved pulmonary aspergillosis cases. A metabolic antigen from a strain ofAspergillus fumigatus according toAjello et al technic modified by us, has been employed. Sera from 120 subjects suffering from non-mycotic lung conditions, as well as 10 sera from histoplasmosis cases, 10 sera from S. A. blastomycosis and 2 sera from patients with lung aspergillosis produced byA. niger, gave negative results with the above mentioned seroligic reactions.One hundred per cent of positive results were obtained with the complement-fixation test (titre ranging from 1/20 to 1/1280), agar-gel immunodiffusion test (titre up to 1/64) and the opposite immunoelectrophoresis (titre ranging from 1/2 to 1/256). Twenty five per cent negative and 4 non-specific results were registered with the latex particle agglutination test.A correlation of the number of serum precipition bands obtained by the electrophoresis technic with the titre of the quantitative serologic reactions, as well as a correlation of the titre of the circulating antibodies with the severity of the clinical form of aspergillosis seems to be present.Electrophoretic motility of the specific antibody performed in 10 sera showed results like the IgM in 1 instance and an intermediate position between IgA and IgG in 9 samples.     

Chronic Cavitary Histoplasmosis of the Lung

Four main clinical types of disease result from infection by the fungus Histoplasma capsulatum: (1) the primary complex; (2) acute pulmonary histoplasmosis; (3) chronic cavitary pulmonary histoplasmosis; (4) disseminated systemic histoplasmosis.Chronic cavitary histoplasmosis of the lung is indistinguishable clinically and radiographically from pulmonary tuberculosis. In this disease, however, the histoplasmin skin test and the histoplasmin complement fixation test are positive in more than 80% of cases and sputum cultures are usually positive for Histoplasma capsulatum. The mortality rate of the chronic cavitary type is greater than 30%. The antibiotic, amphotericin B, is the most effective drug in treatment. If surgical resection of the cavitary lesion is feasible, under amphotericin coverage, this is the treatment of choice.During the past year, two patients with chronic cavitary histoplasmosis illustrating the aforementioned features were diagnosed at the Toronto Hospital for Tuberculosis.     

Soluble Antigens for Immunofluorescence Detection of Histoplasma capsulatum Antibodies

Soluble antigens from Histoplasma capsulatum in the mycelial and yeast phase were purified by gel filtration, fixed onto paper discs, and employed in an indirect immunofluorescence procedure to detect antibody in sera from individuals infected with H. capsulatum. The elution patterns of crude histoplasmin passed through Sephadex G-200 revealed two minor peaks of protein showing immunofluorescence, complement fixing, and precipitating-antigen activity. A large peak containing the pigment and other low molecular weight materials showed no serological activity. A polysaccharide antigen obtained from fragmented, deproteinized yeast-phase cells was reactive in the fluorescent-antibody test but showed no antigen activity in complement fixation or precipitin tests. Although certain sera from culturally proven cases of blastomycosis, coccidioidomycosis, and cryptococcosis reacted with the purified Histoplasma antigens, preliminary evaluation indicated that the immunofluorescence technique may be of value as a screening procedure for the serodiagnosis of histoplasmosis.     

The use of latex agglutination tests for determining Campylobacter species

A comparison was made between three commercially available latex agglutination tests for the detection of Campylobacter. All tests showed clear agglutination with pure cultures of several Campylobacter strains in both the spiral and coccoid form. The Microscreen test was able to detect 10 times less cells than the Campyslide and Meritec tests. The latex tests were also applied to enrichment broth cultures of chicken products. Sixty-nine per cent of the Campylobacter positive enrichment broth cultures were positive with the Microscreen test. The Meritec test detected 63% of the positive samples. The Campyslide test detected only 15% of the positive samples and often showed non-specific agglutination.     

Screening for plant lectins by latex agglutination tests

The latex agglutination test has been applied as a detection system for lectins, the method being especially useful in locations where the dependence on blood for hemagglutination tests could be minimised. The binding of various glycoproteins and sugars individually to the latex particles facilitated the agglutination with lectins having varying sugar specificities. The glycoproteins used were ovalbumin, horseradish peroxidase, porcine mucin and fetuin, while N-acetylglucosamine, N-acetylgalactosamine comprised the sugars used for binding to latex. The sensitivity of the latex agglutination tests was comparable with that of hemagglutination tests. Sugar binding specificity of the lectins could also be determined by inhibition of the agglutination in the presence of corresponding free sugars. The method proved to be useful in screening crude seed extracts for the presence of lectins.     

Mycoplasma-latex agglutination reaction

Morton, Harry E. (University of Pennsylvania, Philadelphia). Mycoplasma-latex agglutination reaction. J. Bacteriol. 92:1196-1205. 1966.-The building up of Mycoplasma cell mass through adsorption to carrier particles as a method for enhancing the agglutination reaction to identify Mycoplasma is described. Mycoplasma cells of human, avian, swine, goat, sewage, and tissue-culture origin were adsorbed to latex particles (0.81 mu) and then were agglutinated by immune sera. The adsorption was demonstrated by electron microscopy. Either the cells or their antibodies, depending on which came into contact with the latex particles first, were adsorbed. The test, completed in less than 2 hr, consisted of serially diluting immune sera with buffered saline, adding the antigen, incubating in a water bath, centrifuging, and reading the reaction under 50 x microscope magnification. The antigen in each reaction tube, representing the growth from about 1.6 ml of culture, was estimated to contain 23 mug of protein (approximately one-tenth the amount of Mycoplasma cells needed for a direct agglutination reaction). In the sera from rabbits undergoing immunization with Mycoplasma antigens, the presence of anti-Mycoplasma antibodies was detected much sooner in the Mycoplasma-latex agglutination reaction test than in the agar-gel diffusion reaction and the growth inhibition tests. Four different lots of latex particles showed excellent uniformity of behavior and stability during storage and testing.     

Detection of Hepatitis Associated Antigen by the Latex Agglutination Test

Hepatitis associated antigen may be detected quickly and reliably by the latex agglutination test, using antiserum from guinea pigs immunized with the antigen. The latex test has a sensitivity comparable to the counter current immunoelectrophoresis technique.     

In situ localization of antigens of Histoplasma capsulatum using colloidal gold immune electron microscopy

Histoplasma capsulatum contains multiple antigens, among them the H antigen and M antigen, which are useful in serologic testing for histoplasmosis. We prepared 7 mouse monoclonal antibodies (5 IgG, 2 IgM) to histoplasmin, and compared these with polyclonal histoplasmin antibodies raised in rabbits and mice. Both monoclonal and polyclonal antibodies were high titered by ELISA. Colloidal gold immune electron microscopy (CGIEM) showed that polyclonal antibodies to histoplasmin or H antigen bound at multiple sites in the cell wall, cytoplasm, and nucleus of Histoplasma yeast cells. In contrast, antibodies to M antigen selectively label the cell membrane and antibodies to alkali soluble cell wall antigen label only the cell wall. Polyclonal antibodies cross reacted extensively with other fungi, both by ELISA and CGIEM. Monoclonal antibodies stained only cytoplasmic epitopes, but also cross reacted with other fungi by electron microscopy. Only periodate treated H antigen elicited polyclonal antibodies which were more specific than those of untreated H antigen or histoplasmin.     

Comparison of a Newly Developed Latex Agglutination Test and an Immunodiffusion Test in the Diagnosis of Systemic Candidiasis

A newly developed latex agglutination (LA) test and a modified immunodiffusion (ID) test were evaluated. The antigen used was a homogenate of Candida albicans. A total of 167 antisera were employed in the evaluation. They included 36 sera from clinically well persons; 78 from patients with various clinical forms of candidiasis; 52 from patients with proven cases of aspergillosis, blastomycosis, coccidioidomycosis, cryptococcosis, histoplasmosis, nocardiosis, paracoccidioidomycosis, sporotrichosis, and tuberculosis; and one serum from a patient with toruloposis. Use of the LA test in conjunction with the ID test permitted the detection of more than 90% of 43 proven candidiasis cases. Of all the heterologous cases and normal human sera tested, LA reactions were noted with 3 of 10 cryptococcosis case specimens, 1 of 9 tuberculosis case specimens, and with the torulopsemia case serum. In contrast, the only heterologous serum reactive in the ID test was that from the patient with torulopsemia. Torulopsis glabrata and C. albicans antisera gave identical reactions in LA and ID tests with T. glabrata or C. albicans antigens. ID tests with selected antigens, however, permitted differentiation of rabbit and human T. glabrata antibody from that of C. albicans antibody. Six different precipitins were recognized with the C. albicans antigens. The occurrence of multiple precipitin lines and high LA titers was suggestive of severe candidiasis. The LA test, in contrast to the ID test, appeared to have prognostic value. Together, the LA and ID tests provided a simple, rapid, and accurate means of detecting and monitoring infections by species of Candida.     

Epidemiologic skin test survey of sensitivity to paracoccidioidin,histoplasmin and sporotrichin among gold mine workers of Morro Velho Mining,Brazil

Skin tests with paracoccidioidin, histoplasmin and sporotrichin were applied to 417 workers of Morro Velho Mining in the State of Minas Gerais, Brazil, with the main purpose of detecting the prevalence of paracoccidioidomycosis-infection, histoplasmosis capsulate-infection and sporotrichosis-infection. The rates of positivity to the skin tests were 13.43% for paracoccidioidin, 17.50% for histoplasmin and 13.67% for sporotrichin. Several epidemiological factors were investigated for a better interpretation of the results. Paracoccidioides brasiliensis, Histoplasma capsulatum var. capsulatum and Sporothrix schenkii were not isolated from the soil samples from the mines investigated.     

Specific latex preparations in the etiological diagnosis of suppurative bacterial meningitis

The results of the evaluation of the diagnostic latex preparations Bactigen, manufactured by Wampole Laboratories (USA) and intended for the detection of meningococcal antigens, serogropus A, B, C, Y, pneumococcal polyantigens and type b Haemophilus influenzae antigens in the spinal fluid and blood of patients with meningococcal infection and purulent bacterial meningitides, are presented. The pathological material was studied by traditional methods and by the latex agglutination (LAG) test. 522 LAG tests were made, including 414 tests for meningococcal infection, 60 tests for pneumococcal infection and 48 tests for type b H. influenzae. The results of this study revealed that the latex preparations were highly specific with respect to type b H. influenzae antigens and meningococcal antigens (false positive reactions constituted 0.96%). The simplicity of the test and the rapid techniques making it possible to obtain results within 30-40 minutes indicate good prospects of using the LAG test in laboratory practice.