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Biomedical subjects

A M Deelder

Publications and source records attributed to A M Deelder.

At least 145 records · Page 8Linked to original sources
PubMed1984

Stabilization of the amplification convertase of complement by monoclonal antibodies directed against human factor B.

Three IgM mouse monoclonal antibodies (MoAb), 5B5-A, 2D2-B, and 5B12-A, were prepared by fusion of spleen cells from mice immunized with human B with the SP 2/0 myeloma cell line. They were assessed for their effect on cell-bound and fluid-phase amplification convertases of complement (C) with purified proteins in vitro. 5B5-A and 2D2-B were similar in their effects on cell-bound preformed C3bBb in that they bound to cell-bound C3bBb, stabilized the C3bBb convertase, and rendered the C3bBb convertase relatively resistant to the plasma protein H. These two MoAb were also able to enhance C3 consumption in vitro in reaction mixtures containing C3b, C3, B, and D. At the same time, they presumably stabilized the C3 convertase and caused relative sparing of B hemolytic activity in the reaction mixtures. In contrast, 5B12-A, which also bound to Bb and C3bBb, did not induce any stabilization, but rather caused accelerated decay of cell-bound C3bBb. These results indicate that MoAb against B can have C3NeF-like activity. On the other hand, not all MoAb against B have stabilizing activity on the C3bBb convertase.

Animals↗
PubMed1983

Schistosoma japonicum: immunological characterization and detection of circulating polysaccharide antigens from adult worms.

The antigenic constituents of a trichloroacetic acid (TCA)-soluble fraction of adult Schistosoma japonicum were studied with immunoelectrophoresis, and compared with those of Schistosoma mansoni. Eight TCA-soluble antigens of S. japonicum were demonstrated, five of which showed immunological identity with S. mansoni antigens. Of the eight antigens, five antigens with anodic motility were found as circulating antigens in S. japonicum-infected hamster and rabbit sera; the major circulating antigen was the circulating anodic antigen (CAA). Two other antigens, with cathodic motility, including the circulating cathodic antigen (CCA), were demonstrable as circulating antigens in S. mansoni infections, but not in S. japonicum infections. Most of the circulating antigens were shown to be gut-associated. Only one antigen, line 2, which was not demonstrable as circulating antigen and which was present in the parenchyma of the worms, was found to be specific for S. japonicum. Using an ELISA for the detection of CAA in the sera of S. japonicum-infected rabbits, a lower detection level of 100 ng CAA/ml serum was achieved. Moreover, at 7-8 weeks after infection, a direct relationship between worm burden and CAA level was demonstrated.

Animals↗
PubMed1983

Schistosoma japonicum: immunological response to circulating polysaccharide antigens in rabbits with a light infection.

To study the detectability of circulating polysaccharide antigens and the immunological response to such antigens in rabbits with a light Schistosoma japonicum infection, sera of five rabbits infected with 50 cercariae were studied up to 29 weeks post infection (p.i.). While one rabbit developed no worm burden, the other rabbits developed low worm burdens (4 to 16 worms). In the sera of these rabbits, the only polysaccharide antigen demonstrable with immunoelectrophoresis (IEF), was the circulating anodic antigen (CAA). With the enzyme-linked immunosorbent assay (ELISA), CAA was detectable from 5 to 6 weeks p.i. in the sera of the two rabbits with the highest number of worm couples. The lowest CAA level which was detectable in unconcentrated sera from which serum proteins had been removed was 125 ng CAA/ml, corresponding with a worm burden of 4.5 worm/kg body wt. During the entire infection, CAA-specific immune complexes were only demonstrable in very low concentrations. Antibodies against polysaccharide antigens were assessed with immunofluorescent antibody (IFA) on Rossman's fixed sections of adult worms, with the ELISA, and with IEF. Specific IgA, IgG, and IgM antibodies were detectable from 2 to 3 weeks p.i. with IFA and ELISA. These early antibodies were shown to be directed against gut-associated antigens, while antibodies against parenchyma-associated antigens were found later in the infection. With IEF, antibodies against two trichloroacetic acid (TCA)-soluble antigens were detectable, including the major, S. japonicum-specific antigen 2.

Animals↗
PubMed1983

A monoclonal antibody from infected mice to a Schistosoma mansoni egg proteinase.

A number of monoclonal antibodies were obtained by fusion of SP2/0 myeloma cells and spleen lymphocytes from mice infected with Schistosoma mansoni. These antibodies were tested for their ability to inhibit acidic, thiol-dependent proteinases previously isolated from Schistosoma mansoni eggs and adult worms. One of the monoclonal antibodies isolated inhibits egg proteinase activity measured in vitro with the use of a low m.w. synthetic substrate. This antibody, which is an IgG1 isotype, does not appreciably inhibit an acidic, thiol-dependent proteinase obtained from the adult stage of Schistosoma mansoni. Immunocytochemical methods with the monoclonal antibody have been used to localize the egg proteinase within a set of "penetration" glands in the unhatched miracidium.

Age Factors↗
PubMed1982

Scanning electron microscopical observations on antigen-antibody coat formation on mechanically transformed Schistosoma mansoni schistosomula.

As part of a study of the antigenic composition of the tegument of mechanically transformed Schistosoma mansoni schistosomula, the phenomenon of coat formation around such schistosomula when incubated in medium containing serum of S. mansoni infected mice was investigated with light and scanning electron microscopy. Coat formation was only observed on freshly transformed schistosomula, while schistosomula that had been incubated overnight at 37 degrees C in medium without serum from infected mice were no longer able to produce a coat. When freshly transformed schistosomula were incubated in medium containing serum from infected mice, it was found that individual spines on the tegument were covered with a coat within 1 h. After 2 h of incubation, the schistosomula were completely covered with a thick coat, starting at the posterior end. This coat was actively shed by the schistosomula after 3 h of incubation. To investigate the mechanism of coat formation, experiments were carried out using serum from uninfected mice, heat-inactivated serum from infected mice, and the IgG fraction of serum from infected mice. From the experiments it was concluded that the coat consisted of antigen-antibody complexes, involving IgG antibodies and complement. A detailed analysis of the easily obtainable coats may lead to a better understanding of the antigenic structure of the cercarial and schistosomular tegumental membrane.

Animals↗
PubMed1981

Detection of antibodies against circulating cathodic antigen of Schistosoma mansoni using the enzyme-linked immunosorbent assay.

The applicability of a Schistosoma mansoni polysaccharide antigen, circulating cathodic antigen (CCA), for the detection of antibodies in S. mansoni infection was tested in the enzyme-linked immunosorbent assay (ELISA). Antibodies against this secretory antigen were detected in hamster infections after three weeks, while in infected humans anti-CCA antibodies could be demonstrated eight weeks after infection. Antibodies could be demonstrated both in recent and chronic infections in man, but more false-negative results were observed in chronic infections. The antibody response was composed of both IgM and IgG antibodies.

Adult↗