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Biomedical subjects

S D Chaparas

Publications and source records attributed to S D Chaparas.

At least 55 records · Page 3Linked to original sources
PubMed1978

Delayed hypersensitivity responses of experimental animals to histoplasmin from the yeast and mycelial phases of Histoplasma capsulatum.

Controlled yeast lysate (CYL) and controlled mycelial lysate (CML) histoplasmins were produced from Histoplasma capsulatum grown in a nutritionally lean, chemically defined medium. The lysates were assayed for skin-test activity in guinea pigs sensitized by infection with the homologous organism. In some studies, nonliving vaccine preparations were employed also. Inter-lot biological variation was minimal, and 20 lots of the CYL reagent elicited strong dermal reactions with high specificity. Further, CYL reagents were nonreactive in guinea pigs infected with Coccidioides immitis, whereas the commercial Food and Drug Administration preparations cross-reacted to some degree. The CML histoplasmins were generally less reactive than the CYL preparations and exhibited somewhat more inter-lot variation in sensitivity and specificity. No correlation between potency and protein:polysaccharide ratios were observed with either reagent. An intradermal test with the CYL reagent did not induce significant changes in the complement-fixing titer of sensitized guinea pigs. Such changes in sensitized animals were elicited by a skin test with commercial histoplasmin.

Animals↗
PubMed1978

An analysis of cross reactions among mycobacteria by in vivo and in vitro assays of cellular hypersensitivity.

Homologous and heterologous skin test reactions in sensitized guinea pigs to antigens from 11 species of mycobacteria were fitted by a linear model that permitted the ranking of each species on the basis of cross reactivity. When the same species were ranked on the basis of in vitro transformation of sensitive lymphocytes in response to homologous and heterologous antigen preparations, a different ranking order was observed. Reasons for the lack of strict correlation between skin tests and in vitro lymphocyte transformations are discussed.

Animals↗
PubMed1978

Antigenic relationships of various mycobacterial species with Mycobacterium tuberculosis.

Antigen cross reactivity of various mycobacterial sonicates with Mycobacterium tuberculosis was studied by fused rocket immunoelectrophoresis using 2 Mycobacterium tuberculosis reference antisera. A considerable degree of cross reactivity was noted with both antisera, and each anti-serum revealed different information about the antigenic complexities between mycobacteria.

Antigens, Bacterial↗
PubMed1978

Characterization of antigens from Aspergillus fumigatus. I. Preparation of antigens from organisms grown in completely synthetic medium.

Aspergillus fumigatus was found to grow well in completely synthetic asparagine glycerol medium. Four-day-old mycelia were totally disrupted by vigorous mechanical shaking with 0.45-micrometer glass beads. Such mechanically produced extracts contained at least 52 precipitating antigens. The number of protein and carbohydrate components was maximal in 4-day-old organisms and decreased in older cultures. Conversely, the number of components in culture filtrates increased with longer incubation periods, but was only approximately one-half that produced by the 4-day-old mycelial extracts.

Animals↗
PubMed1978

Characterization of antigens from Aspergillus fumigatus. II. Fractionation and electrophoretic, immunologic, and biologic activity.

Mycelial extracts of Aspergillus fumigatus grown in completely synthetic medium were fractionated by precipitation with ammonium sulfate, by ion-exchange chromatography, and by gel filtration. The fractions were characterized chemically, by analytic polyacrylamide gel electrophoresis, and by tests for serologic and biologic activity. The distribution of the antigens in the fractions was determined by double diffusion in gel and fused-rocket immunoelectrophoresis. Activity greater than that of the parent mycelial extract serologically, in guinea pig skin tests, and in in vitro lymphocyte transformation was observed with one fraction that was found in the 75 per cent ammonium sulfate precipitable portion and was eluted early by gel filtration. Another ammonium sulfate-precipitable component and one that was not precipitable at 75 per cent ammonium sulfate, but was firmly bound by ion-exchange columns, was found to have activity equal to unfractionated mycelial extract. These fractions were also active by a radioallergosorbent test for IgE. A carbohydrate component comprising almost 40 per cent of mycelial extract was found to be devoid of any immunologic activity.

Animals↗
PubMed1977

Effect of Corynebacterium parvum, methanol-extraction residue of BCG, and levamisole on macrophage random migration, chemotaxis, and pinocytosis.

Three parameters of macrophage function: random migration, chemotaxis, and pinocytosis, were studied in the guinea pig after administration of Corynebacterium parvum, methanol-extraction residue of BCG, and levamisole (LMS), a synthetic anthelmintic. Macrophage migration studies were performed with a modified Boyden chamber. Pinocytosis was assessed by the uptake of colloidal 198Au. After ip administration, each of the three immunostimulators induced an increase in macrophage chemotactic responsiveness and, to a lesser extent and duration, in random motility. Kinetic, dose-response, and time course data for the effect of each agent on macrophage movement were explored. LMS was the most effective stimulator of macrophage activation, which occurred earlier and persisted longer than it did with the other agents. Macrophages from animals receiving each of the agents showed enhanced pinocytosis. Measurement of macrophage random migration, chemotaxis, and pinocytosis appeared to provide a rapid and quantitative assessment of several parameters of macrophage function and, when studied with other immunologic parameters, may provide useful tools for the evaluation of potential immunoadjuvants.

Animals↗
PubMed1977

A comparative study of the 'rhodochrous' complex and related taxa by delayed-type skin reactions on guinea pigs and by polyacrylamide gel electrophoresis.

Cell extracts prepared by ultrasonic disruption of 17 strains of the 'rhodochrous' complex and related taxa were compared by polyacrylamide gel electrophoresis and for immunologic relatedness, by skin test reactions. Two organisms, Jensenia canicruria and Nocardia calcarea, gave similar gel patterns and skin test reactions, and are considered to be identical. Extracts of nocardia rubra showed a strong antigenic relationship with those of three Nocardia pellegrino organisms (N325, N324 and N420) previously assigned to the 'rhodochrous' complex. Two Gordona organisms appeared to be less antigenically related to the 'rhodochrous' complex. Extracts of three of four organisms designated Lspi (Rhodococcus coprophilus Rowbotham & Cross 1976) elicited skin test reactions similar to those of the 'rhodochrous' strains. One Lspi strain, N650, showed striking similarities to the 'rhodochrous' complex strain N420 (Nocardia pellegrino).

Animals↗
PubMed1976

Comparison of antigens in sonic and pressure cell extracts of Mycobacterium tuberculosis.

Comparisons were made of the yield, chemical content, and biological activity of filtrates and extracts obtained by sonic and pressure cell disruption of bacilli from 4- and 8-week-old Proskauer and Beck cultures of the H37Rv strain (TMC no. 102) of Mycobacterium tuberculosis. The culture filtrates were dialyzed, freeze-dried, reconstituted in saline, and sterilized by membrane filtration. The viable bacilli were washed and resuspended in distilled water and subsequently disrupted either by sonication in the cold for 15 or 30 min or by treatment at 20,000 or 40,000 lb/in2 in a pressure cell. The resulting extracts were clarified by centrifugation, concentrated, and sterilized by filtration. All preparations were adjusted to contain 10 mg of solids (dry weight)/ml and were analyzed quantitatively for protein, deoxyribonucleic acid, ribonucleic acid, polysaccharide, and lipid content. Separation patterns obtained by gradient acrylamide gel electrophoresis, as well as by one- and two-dimensional immunoelectrophoresis, provided the basis for qualitative comparisons of the culture filtrates and cell extracts. Three-point dose-response curves also were used to compare the preparations for skin test reactivity in BCG-vaccinated guinea pigs. It was concluded that, although there were no consistent differences in chemical content or biological activity between the preparations, a 15-min sonic treatment appeared to be the most suitable method for preparation of bacillary extracts based on yield of active components and ease of preparation.

Animals↗
PubMed1976

Contrasting effects of BCG on spleen and lymph node antibody responses in nude and normal mice.

Subcutaneous footpad injection of BCG causes a marked augmentation of popliteal lymph node plaque-forming cell (PFC) responses to DNP-derivatized hemocyanin and to sheep red blood cells, both T-dependent antigens, but not to DNP-derivatized Ficoll, a T-independent antigen. This augmentative effect occurs in normal thymus-bearing heterozygous (nu/+) mice, but not in congenitally athymic nude mice (nu/nu). In contrast, intravenous injection of BCG causes a suppressed splenic PFC response to subsequently administered T-dependent or T-independent antigens in both nude and nu/+ mice. BCG's augmenting effect on the lymph node appears to be mediated by a T-helper cell. BCG's suppressive effect in the spleen is not attributable to T cells. The actual mechanism of the BCG-mediated suppressive splenic effect remains incompletely defined at present.

Animals↗
PubMed1976

The effect of Mycobacterium bovis (Bacillus Calmette-Guérin) on macrophage random migration, chemotaxis, and pinocytosis.

Macrophage random migration, chemotactic responsiveness, and pinocytosis were studied in the guinea pig after Bacillus Calmette-Guérin (BCG) administration. Oil-induced peritoneal exudate cells were evaluated for random migration and chemotaxis in modified Boyden chambers. Pinocytosis was measured by the in vitro uptake of colloidal 198Au. There was a parallel increase in random migration and chemotaxis after an i.p. dose of 1.0 X 10(7) COLONY-FORMING UNIts of BCG. This was seen as early as Day 4, sustained through Day 21, and absent by Day 44. A number of different strains and preparations of BCG vaccine exerted a similar augmentation of macrophage mobility. In parallel assays, aliquots of macrophages from BCG-treated animals showed increased pinocytosis, first noted at Day 14, peaking at Day 28, and no longer measurable at Day 44. These alterations in macrophage function following BCG administration may in part contribute to the antitumor effect of BCG adjuvant therapy.

Animals↗
PubMed1975

Response of congenitally athymic (nude) mice to infection with Mycobacterium bovis (strain BCG).

Mice homozygous for the mutation "nude" (nu/nu) are athymic and lack thymus-dependent lymphocytes. Heterozygote (nu/+) controls, which are phenotypically and immunologically normal, and (nu/nu) mice were infected with 1.0 times 10-6 colony-forming units of Phipps strain BCG. In the spleens of nu/+ mice, there was a progressive increase in number of BCG up to the second week, followed by a gradual decline. However, in the nu/nu mice, BCG growth was gradual and continuous until termination of the experiment at 5 weeks. In the lung, significant differences were not noted until after the second week, at which time the nude mice showed a rapid increase (of more than 2 log10) in the number of BCG. However, the number of BCG was not significantly greater in the livers of either group. Changes in the normal histology of the lung included a massive influx of monocytes during the first 2 weeks which peaked at day 21. In the lungs of the nu/+ mice by day 28, there was considerable granuloma formation consisting of monocytes and small lymphocytes. However, in the lungs of nu/nu animals, the granulomas were made up primarily of monocytes with a lack of small lymphocytes. Acid-fast stains confirmed the presence of large numbers of organisms in the macrophages of nu/nu mice, with gradual destruction of these phagocytic cells.

Animals↗
PubMed1975

Effects of BCG, Corynebacterium parvum, and methanol-extration residue in the reduction of mortality from Staphylococcus aureus and Candida albicans infections in immunosuppressed mice.

An immunosuppressed mouse model was devised to test the effects of immunopotentiators on the prevention of bacterial and fungal infections. The effects of BCG and Corynebacterium were tested against Staphylococcus aureus and Candida albicans infection. The effect of methanol-extraction residue (MER-BCG) was tested against S. aureus septicemia. CDF mice were given various doses of BCG, 1.0 mg of C. parvum, or 0.5 mg of MER intraperitoneally at varying intervals before injection of an intravenous bacterial challenge. Four days before challenge, 300 mg of cyclophosphamide per ml was given intraperitoneally. BCG (106 colony-forming units) reduced mortality due to S.aureus at pretreatment intervals of 3, 7, 14, and 28 days. Isonicotinic acid hydrazide treatment elimated the protective effect of the live BCG. C. parvum was as effective as BCG against S. aureus septicemia when given 3 days before infection, but lost most of its protective effect after that time. MER protected at doses as small as 0.25 mg when given 25 days prior to challenge. Both BCG and C. parvum exerted a protective effect against Candida albicans infection.

Animals↗
PubMed1975

Tuberculin-induced lymphocyte transformation and skin reactivity in monkeys vaccinated or not vaccinated with Bacille Calmette-Guérin, then challenged with virulent Mycobacterium tuberculosis.

The in vitro lymphocyte transformation test was compared to the skin test at intervals after aerogenic administration of bacille Calmette-Guerin vaccine to monkeys, and also at monthly intervals after aerogenic challenge of monkeys vaccinated and not vaccinated with virulent strain H37Rv of Mycobacterium tuberculosis. Individual responses varied, but several consistent patterns of sensitivity development could be discerned. The lymphocyte transformation test was more sensitive, and often positive when the skin test was negative, doubtful, or feeble. Conversion to tuberculin reactivity was detected by lymphocyte transformation in vitro earlier in the disease or after vaccination, and persisted longer after sensitivity to the skin test had waned or after the animals had become anergic by the skin test. Monkeys not vaccinated, but challenged, developed larger in vitro skin reactions and responses than animals that were either vaccinated and challenged or only vaccinated; however, the unvaccinated, challenged monkeys developed anergy to tuberculin and progressive disease more rapidly than other groups, and their cells became less responsive to phytohemagglutinin in vitro.

Animals↗