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Biomedical subjects

S D Chaparas

Publications and source records attributed to S D Chaparas.

At least 37 records · Page 2Linked to original sources
PubMed1986

Sensitivity and specificity of enzyme-linked immunosorbent assay in the detection of antigen in tuberculous meningitis cerebrospinal fluids.

A sandwich enzyme-linked immunosorbent assay was developed for its potential utility in the detection of antigen in the cerebrospinal fluid of patients with tuberculous meningitis. Cerebrospinal fluids examined included those from untreated (group Ia) and treated (group Ib) Mycobacterium tuberculosis meningitis, nonseptic central nervous conditions (group II) such as epilepsy, viral meningitis, and tetany, and nonmycobacterial septic meningitis (group III). The average levels of antigens determined and percent positive specimens, respectively, for each group were (group): Ia, 1.8 micrograms/ml and 75% positive; Ib, 0.37 microgram/ml and 36% positive; II, 0.036 microgram/ml and 100% negative; and III, 0.075 microgram/ml and 100% negative. The system developed employed hyperimmune polyclonal antibody raised against M. tuberculosis and Mycobacterium bovis BCG in burros and rabbits. Cross-reactivity by other mycobacterial species was very low; e.g., 5% for M. kansasii and less than 2% for M. intracellulare, M. avium, M. vaccae, and M. fortuitum. The test shows promise as a specific adjunct for the early diagnosis of tuberculous meningitis.

Antigens, Bacterial↗
PubMed1986

Serologic and cellular cross-reactivity of fractions of Mycobacterium intracellulare (Battey).

Sonicates of Mycobacterium intracellulare grown in synthetic medium were separated into ammonium sulfate (50%) precipitable and nonprecipitable fractions. Gel filtration of the precipitable fraction through columns of Sephacryl S-300 resulted in four fractions labeled A, B, C and D in order of elution. Fractions C and D were further fractionated into 12 and 13 subfractions, respectively. The subfractions were examined for reactivity by rocket immunoelectrophoresis (R-IE) procedures and by skin tests in homologously and heterologously immunized guinea pigs (M. kansasii, M. fortuitum, M. marinum, M. scrofulaceum and M. bovis). Extensive sharing of antigenic determinants was observed for all of the reactive subfractions by R-IE. None of the subfractions showed significant skin test specificity. Possible reasons for the nonspecificity are discussed.

Animals↗
PubMed1986

Dialyzable tuberculins: their abilities to participate in or inhibit immune reactions.

Dialyzable components of culture filtrate of Mycobacterium bovis were fractionated by gel filtration on Sephadex G-10 into eight fractions, A through H in order of their elution from the column. None of the fractions produced a visible precipitate when reacted with a hyperimmune antiserum. The first five fractions were further investigated. All were capable of inhibiting precipitation of nondialyzable tuberculin. Fraction E, containing the smallest fragments, totally abolished precipitation and fraction A, which contained the largest molecules inhibited the least. Fractions A and B were the only ones that could induce skin reactions in sensitized guinea pigs but did this poorly. In vitro transformation of PPD sensitized lymphocytes was induced only by fraction A. Only fractions A and B could inhibit transformation of lymphocytes by Concanavalin A but only fraction B could inhibit transformation by tuberculin. Dialyzable components injected intracardially 3 hours prior to skin testing with tuberculin caused a reduction in skin reactivity. Since such substances are present in tissues in late stages of tuberculosis investigations were made to determine if they played a role in the induction of the observed accompanying tolerance to skin test cellular hypersensitivity. Guinea pigs treated with dialyzable components prior to and for four weeks post sensitization did not develop tolerance.

Animals↗
PubMed1984

Genetic resistance of mice to persistent infection with Mycobacterium lepraemurium in vitro: association with macrophage bactericidal responsiveness to lymphokines and dissociation from production of hydrogen peroxide by macrophages.

Peritoneal and splenic adherent macrophages (SAC) from M. lepraemurium susceptible (C3H/HeJ) and resistant (C57B1/6J) mice were studied for their abilities to generate H2O2 in vitro. Unexpectedly, SAC from the susceptible C3H/HeJ strain produced more H2O2 than those of the resistant C57BL/6J. In vivo sensitization with M. bovis (BCG), or C. parvum increased production of H2O2 by SAC from both strains, whereas in vivo sensitization with M. lepraemurium enhanced H2O2 production only in the C3H/HeJ susceptible strains. In vitro addition of a crude lymphokine enhanced H2O2 production by C3H/HeJ SAC more than by C57BL/6J SAC. In vitro addition of M. lepraemurium caused an inhibition of H2O2 production by SAC from both strains but the inhibition was greater for the resistant C57BL/6J strain. M. lepraemurium phagocytosed in vitro by untreated peritoneal macrophages of both mouse strains were morphologically altered to the same extent. However, the addition of lymphokine dramatically increased the degree of bacterial lysis in only the C57BL/6J strain. These results, support the view that H2O2 plays a limited, if any, role in the protection of the host from M. lepraemurium and may even contribute to susceptibility by inhibiting the host's immune response.

Animals↗
PubMed1982

The immunology of mycobacterial infections.

Mycobacteria are endowed with substances that profoundly affect the immune system. Leprosy and tuberculosis exemplify broad spectra of useful and detrimental immune responses of mycobacterial infections that range from intense potentiation to severe specific adn nonspecific suppression of humoral and cellular immune elements. The cellular hypersensitivity induced by mycobacteria serves as a classical model for the analysis of specific and nonspecific immune mechanisms. Mycobacterial disease are prevalent worldwide and rank among the most important bacterial diseases. The kaleidoscope of immunologic events induced by injected mycobacteria and during infections will be reviewed from the standpoint of pathogenesis, pathology, in vitro and in vivo effects on cellular and humoral arms of the immune response, diagnosis, classification, potentiation and suppression.

Animals↗
PubMed1980

Profiles of skin test reactivity to antigens of various mycobacterial species in a human population and in experimental infections.

Sensitivity profiles to 6 mycobacterial skin test antigens prepared from Mycobacterium tuberculosis, M. kansasii, M. scrofulaceum, M. intracellulare, M. avium and M. fortuitum were obtained in 6 groups of guinea pigs, each infected with one of the 6 mycobacterial species. Each group of animals showed the greatest sensitivity towards the homologous antigen. A second infection with a different species was super-imposed two months after the skin tests; the sensitivity towards the second species usually became dominant. Sensitivity profiles with the 6 antigens in a large random sample of the population of a district of Haiti resembled closely the sensitivity profiles for all the guinea pigs infected with two mycobacterial species. This suggested that the Haitian population consisted of a mixture of persons infected with one or more mycobacteria. Haitians with the largest to an antigen, which was at least 6 mm in diameter and at least 2 mm larger than the reaction to any other antigen, were assumed to be infected with the corresponding mycobacterial species. Sensitivity profiles of these persons resembled closely the sensitivity profiles of guinea pigs infected with the same species. In the Haitian population prevalence of infection with other mycobacterial species was much more common than infection with M tuberculosis. In spite of this, after 15 years of age only the tuberculosis infection rates increased with age, suggesting that allergy produced by M. tuberculosis infection was stronger and subject to much less waning than allergy produced by other mycobacterial infections.

Adolescent↗
PubMed1980

In vitro and in vivo reactivity and specificity of fractions from sonicates of Mycobacterium tuberculosis separated by gradient acrylamide gel electrophoresis.

Fractions of cell sonicates from the H37Rv strain of Mycobacterium tuberculosis prepared by gradient acrylamide gel electrophoresis (GAGE) were examined by immunoelectrophoretic analysis and tested for biologic reactivity and antigenic specificity. Each was tested for the ability to elicit delayed type hypersensitivity reactions in the skin of guinea pigs sensitized with M. tuberculosis, M. kansasii, M. intracellulare (Battey), M. scrofulaceum (Gause), and M. fortuitum. Peripheral lymphocytes from persons infected with mycobacteria were also exposed to fractions, and the increase in [3H]thymidine incorporation into DNA was used as an index of stimulation (lymphocyte transformation). Only 4 fractions (6, 11, 12, and 16) were found to be significantly more specific than the unfractionated sonicate, and none was monospecific for M. tuberculosis. The results of fused rocket immunoelectrophoresis suggested that incomplete separation of antigens and/or shared group-specific multideterminant antigens may have accounted for the observed cross-reactions.

Animals↗
PubMed1980

Analytical gradient polyacrylamide gel-crossed line immunoelectrophores. A technique for locating species specific Mycobacterium tuberculosis H37RV antigens in polyacrylamide gel columns.

Analytical gradient polyacrylamide gel electrophoresis of antigens from Mycobacterium tuberculosis H37RV was combined with crossed line immunoelectrophoresis to locate the position of antigens in polyacrylamide gel columns that appeared to be specific for M. tuberculosis H37RV. Specificity was established by comparing H37RV with M. kansaii CE in the electrophoretic procedure and the relative mobility (Rm) values are being used in an effort to recover and enrich specific antigens from preparative gel columns. Such fractions should be more suitable in efforts to recover purified monospecific components from M. tuberculosis H37RV.

Antigens, Bacterial↗
PubMed1980

Antigenic evaluation of mycobacterium vaccae in relation to Mycobacterium leprae.

Immunodiffusion analysis of Mycobacterium vaccae indicated the presence of at least nine antigens. Using the technique of fused rocket immunoelectrophoresis, at least 13 such antigens were detected. Comparative analysis of the M. vaccae antigen-antibody system with similar systems established for other mycobacterial species showed that M. vaccae shared a significant number of antigens with both typical and atypical mycobacteria. These included the already described beta and delta antigens that are common to the majority of mycobacterial species. Confirmation of the presence of these two antigens was obtained through comparative analysis of sera from leprosy patients, using M. vaccae and M. smegmatis conjointly. It has been concluded that M. vaccae possess the two most commonly shared antigens among various mycobacterial species, in addition to many others. It has not been possible with the methods employed to establish any particularly close immunological relationship between M. vaccae and M. leprae that would indicate the use of M. vaccae as a possible antileprosy vaccine source although this possibility has been suggested by other investigators.

Animals↗
PubMed1979

Histoplasmin-CYL, a yeast phase reagent in skin test studies with humans.

A yeast phase histoplasmin, designated CYL, was studied in 156 humans living in areas of the United States endemic for histoplasmosis, coccidioidomycosis, or both fungal entities. Comparisons were made with Food and Drug Administration reference mycelial histoplasmin. Among persons without concurrent spherulin sensitivity, reactor rates and sizes were the same with both reagents. Some persons with spherulin sensitivity reacted only to the mycelial reagent. Histoplasmin-CYL skin tests did not induce significant changes in complement-fixing antibody in histoplasmin-reactive subjects.

Antibodies, Fungal↗
PubMed1979

Characterization of antigens from Aspergillus fumigatus. III. Comparison of antigenic relationships of clinically important aspergilli.

Antigenic relationships between strains of Aspergillus fumigatus, Aspergillus fumigatus var. elipticus, Aspergillus phialiseptus, Aspergillus flavus, and Aspergillus niger were analyzed by fused rocket immunoelectrophoresis and by skin tests. Seventy-three to 89 % of the numbers of antigens detected between strains and species of the A. fumigatus series were shared. The degree of sharing between antigens of A. flavus, A. fumigatus series, and A. niger was much lower and ranged from 19 to 35 %. In reciprocal skin tests in sensitized guinea pigs, similar relationships were shown. Three fractions of A. fumigatus extract proved to be markedly specific for this species. Cross reactivity was associated primarily with carbohydrate and glycoprotein fractions.

Animals↗
PubMed1979

Characterization of antigens from Aspergillus fumigatus. IV. Evaluation of commercial and experimental preparations and fractions in the detection of antibody in aspergillosis.

Commercially available preparations of Aspergillus fumigatus, experimental extracts and fractions of A. fumigatus, and extracts of 5 other aspergilli were evaluated in a blind manner for their abilities to detect antibody in 66 serum specimens from patients with aspergilloma, allergic bronchopulmonary and invasive aspergillosis, and unconfirmed aspergillosis. Rocket immunoelectrophoresis was more sensitive than immunodiffusion in 2 dimensions. Although qualitative differences in antigen composition could be detected, commercial preparations compared favorably with the best experimental extracts in detecting positive specimens. Extracts from young, actively-growing myceliums were most effective and produced the largest numbers of precipitin bands. In contrast to all unfractionated preparations, several fractions of A. fumigatus were devoid of substances that react with C-reactive protein of serums, yet were as effective as the best preparations in detecting serums positive for Aspergillus.

Antibodies, Fungal↗