Search PubMed⌕ Search

Biomedical subjects

F R Seiler

Publications and source records attributed to F R Seiler.

18 recordsLinked to original sources
PubMed1979

A new method for fluorescence immunoassay using plane surface solid phases (FIAPS).

A method distinguished by high sensitivity, low non-specific binding, easy handling, and broad applicability with respect to various antigens is described. Films of polymethyl-methacrylate with plane surfaces were selected as solid phase for adhesive or covalent binding of different antigens (DNA, histone, human, rabbit or goat immunoglobulins). Proteins were covalently bound to the films by the azide method (Orth and Brummer, 1972). Polymethylmethacrylate films thus coated had a negligible autofluorescence and gave minimal non-specific binding of protein. Coated films were used for specificity control of FITC-labeled antibody preparations and in the double antibody and sandwich techniques for detection of antibodies or antigens in sera from man, rabbit and goat. FITC-conjugated hyperimmune antibody, in some cases purified by immunoadsorption was used as second antibody in indirect techniques. The amount of fluorescent-labeled antibody bound per unit of surface area of film was measured by incident light with a Zeiss-Axiomat fluorescence microscope equipped for fluorescence photometry and an uranyl acetate glass plate was used as a standard. The technique appears superior to present methods of quantitative immunofluorescence analysis.

Animals↗
PubMed1979

Antigen-specific detection of HBsAG-containing immune complexes in the course of hepatitis B virus infection.

In recent studies extrahepatic manifestations of viral hepatitis have been recognized as immune complex diseases. Hepatitis B surface antigen (HBsAg) has been successfully identified in immune complexes, but the pathogenic role of HBsAg-containing immune complexes (IC) remains questionable. The subject of the present study was the antigen-specific determination of IC in the course of hepatitis B virus infection using a new HBsAg-specific IC test (Pernice & Sedlacek, 1978). This test is based on the following principle: rabbit anti-HBs-coated polystyrole test tubes are incubated with the IC-containing test sample. The HBsAg-containing IC bind to the solid phase by their free antigenic determinants. There they can be quantified using a peroxidase-labelled anti-human IgG antibody. A good correlation was found between the level of HBsAg-containing immune complexes and the clinical state of six patients in a follow-up study. IC could be detected simultaneously with HBsAg and either decreased or disappeared before the occurrence of free anti-HBs. In the sera of an additional twenty-eight patient suffering from chronic active hepatitis, HBsAg-containing immune complexes were detected in 85% of cases. One patient suffering from polyarteritis nodosa was also positive. Occasionally, extremely high levels of IC were found in the course of these diseases.

Antigen-Antibody Complex↗
PubMed1979

Comparison of several in vitro assay methods for the quantitative determination of complement consumption ('binding') by gammaglobulin preparations.

Unspecifically induced activation of Complement (C) in solution can be caused either by denatured Ig molecules and by polymeric aggregates of same or more specifically by antigen-antibody complexes. As a quality criteria, e.g. for i.v.-IgG preparations, it is agreed by the majority of people concerned that the activation of C via the classical pathway might not be unspecifically initiated. Therefore, the generally used assay systems are based on quantitating the degree of consumption of C undergoing an antigen-independent, 'frustrated' activation via the classical pathway. There are principally two different types of test modifications which were investigated: a) C is being kept constant and protein is diluted or b) protein is being kept constant and C is titrated. When a group of differing IgG preparations or IgG fragments was assayed for its so-called 'anticomplementary' activity in various already described test methods, the particular test results from the individual test methods could not unequivocally be compared with each other because some of the methods had not been optimized with regard to the amount of reagents or test substance used; only a rough estimate of the data was obtained. The value of the not standardized assays remains, therefore, questionable reasonably good and reproducible results are obtained when the amount in particular of C added as well as its quality have been adequately optimized and standardized. This allows a refined differentiation of various IgG preparations by a reliable and unadjusted quantitation of C consumption. If for example, inappropriate and not optimized rations of C amboceptor (e.g. slight C excess) was used, a suppressed C consumption was found. It seems advisable to accept prophylactic testing of anticomplementary activity for quality control as one out of several other in vitro and in vivo parameters which potentially might predict safety for the patient, the physician, and also for the producer. However, it is agreed that, irrespective of in vitro tests, in vivo testing in animals and clinical proof of safety is undoubtedly needed.

Animals↗
PubMed1978

Effect of Vibrio cholerae neuraminidase on the phagocytosis of E. coli by macrophages in vivo and in vitro.

The mechanisms by which Vibrio cholerae neuraminidase VCN acts as an adjuvant is unclear. We have studied the effect of VCN on the phagocyotsis of E. coli 0111 K58 by macrophages in vivo and in vitro. (1) Using and in vivo intraperitoneal clearance test we have shown that prior injection of VCN (50 units/mouse) into the peritoneal cavity of mice enhances the clearance of the bacteria as efficiently as an optimal amount of opsonizing antiserum. We have also shown that the enhancement of intraperitoneal clearance by VCN is due to phagocytosis and intracellular killing of the organisms by macrophages. (2) VCN does not enhance the i.v. clearance of E. coli o111 K58. (3) VCN promotes the attachment of the organisms to and phagocytosis by peritoneal macrophages in vitro. Data are provided which suggest that the promotion of attachment and phagocytosis by VCN cannot be explained by a mere increase of passive absorption of the bacteria to the cell wall.

Animals↗
PubMed1977

Neuraminidase and tumor immunotherapy.

Preliminary results of first clinical studies with the enzyme neuraminidase call attention to a new kind of cancer treatment. This promising approach to tumor immunotherapy was entered into the clinical phase as a consequence of successful experimental studies in tumor-bearing mice, rats and dogs. In this review, the presently known and essential results of experimental and clinical studies on tumor immunotherapy by means of neuraminidase are presented as well as some necessary and critical considerations in this context. Moreover, out of a broad variety of results of biochemical and biological in vitro studies, it was attempted to select the more essential knowledge which could contribute to a better understanding of the still rather unclear in vivo mode of action of the enzyme neuraminidase. In a first brief paragraph (1.0), the biochemically characteristic data of the enzyme neuraminidase is presented. In the second section (2.0), the basic knowledge about the effects of neuraminidase on cell behavior is rather amply contained. Here, on the one hand, the biophysical and biochemical alterations are mentioned, the so-called ""unmasking'' effects are reconsidered and, on the other hand, the effects on the immunologically responding cell are discussed. In a third section (3.0), the diverse findings from animal experiments using neuraminidase-treated tumor cells are confronted, whereby tumor transplantation experiments and tumor therapy experiments are dealt with separately. The last section (4.0) reports about the first clinical studies with neuraminidase-treated autologous as well as homologous tumor cells, which partly brought about rather surprising and astonishing success. On the basis of recent findings by the study group of the authors, the more prior and sometimes discrepant results of various groups are critically considered. The problems of alteration of antigenicity and of other properties of cells through splitting off membrane-bound neuraminic acid, the facts of adjuvanticity of neuraminidase itself, the relation of successful therapy to dose dependency as well as the relation of undesirable methods for tumor mass reduction to the immunological responsiveness of the tumor bearer were especially looked into.

Animals↗
PubMed1976

Development, production and quality control of clinically applied antilymphocyte globulin.

Various antigens have been assessed for the ability to produce anti-human lymphocyte globulin(ALG). In our hands the most satisfactory antigen has proved to be cultured lymphoblasts. These are used to produce Behringwerke ALG(Pressimmune). A brief outline of problems in the large scale production of ALG and how these are overcome is given. The quality control checks for activity and safety are discussed.

Animals↗
PubMed1975

Regression of spontaneous mammary tumors in dogs after injection of neuraminidase-treated tumor cells.

The effect on tumor progression produced by the injection of VCN-treated tumor cells in dogs with spontaneous mammary tumors was investigated. Untreated dogs of different races and different ages with at least two palpable spontaneous mammary tumors were selected. One of the tumors was left in the animal for further clinical examination whereas the other tumor(s) was (were) excised for preparation of a single-cell suspension by mechanical disintegration and enzymatic digestion with collagenase and trypsin. (1) In the first group, each animal was infected with 2 times 10-7 similarly prepared autologous, mitomycin-treated tumor cells; in 8 out of 12 dogs of this group the tumors progressed while so far 1 dog has died of metastasis. (2) In the second group, each animal received the same number of 2 times 10-7 tumor cells, which were mitomycin- and VCN-treated: 13 out of 15 dogs had a significant regression of their tumors to less than 10% of the original volume; in 1 dog the tumor remained unchanged and in 1 dog it progressed. (3) In the third group, 8 dogs received 1 times 10-8 mitomycin- and VCN-treated tumor cells: the application of this cell dose resulted in an accelerated tumor progression in all 8 dogs, 3 of which have already died of metastasis. The significance of these findings, with respect to potentiation and abrogation of the immunological response and with regard to immunotherapy in man, is discussed.

Animals↗