scholarly journals A mechanism for the induction of immunological tolerance by antigen feeding: antigen-antibody complexes.

1975 ◽  
Vol 142 (6) ◽  
pp. 1509-1519 ◽  
Author(s):  
C André ◽  
J F Heremans ◽  
J P Vaerman ◽  
C L Cambiaso
Keyword(s):  
Rheumatoid Factor ◽  
Immune Complexes ◽  
Immunological Tolerance ◽  
Antibody Activity ◽  
Previous Contact ◽  
Primary Type ◽  
A Site ◽  
Antigen Antibody

We have previously reported on the induction, in mice, of a systemic (splenic) immune response with IgA as the dominant antibody, as a result of a short (4 day) intragastric immunization course with foreign erythrocytes. This response was followed by a prolonged period of hyporesponsiveness to similarly administered antigen. Here it is shown that this hyporesponsiveness is also manifested towards antigen given intraperitoneally, and that one is therefore dealing with tolerance, not with failure to absorb antigen from the gut. In contrast, mice primed parenterally and then challenged intragastrically behaved as if never having any previous contact with the antigen, i.e., with a primary-type splenic response of predominant IgA character. This agrees with our former conclusion that splenic responses to enterically absorbed antigen reflect colonization of the spleen by cells sensitized locally in the gut wall, a site not readily primed by the parenteral route. Serum from intragastrically immunized mice contained a very active tolerogen. In vivo, it was capable of conferring tolerance to nonimmune recipient mice. In vitro, it paralyzed the activity of antibody-producing cells. Inhibitory sera has weak antibody activity, restricted to the IgA class, and contained immune complexes reacting with rheumatoid factor but not with C1q. Elimination of these complexes by means by insolubilized rheumatoid factor abolished the tolerogenic effect. In conclusion, the enterically induced tolerogen seems to consist of immune complexes with IgA as the antibody.

scholarly journals THE LOCALIZATION OF IN VIVO BOUND COMPLEMENT IN TISSUE SECTIONS

1962 ◽  
Vol 115 (1) ◽  
pp. 63-82 ◽  
Author(s):  
P. J. Lachmann ◽  
H. J. Müller-Eberhard ◽  
H. G. Kunkel ◽  
F. Paronetto
Keyword(s):  
Rheumatoid Factor ◽  
Binding Sites ◽  
Complement Fixation ◽  
Complement Component ◽  
Tissue Sections ◽  
Antigen Antibody ◽  
Human Complement Component ◽  
Immunofluorescent Method

A technique has been described for the demonstration of a human complement component by an immunofluorescent method. The component detected is ß1C-globulin, a moiety of the third complement component, which has previously been obtained in pure form and to which a specific antiserum has been prepared. It has been shown in a model system that the binding of ß1C-globulin as shown by immunofluorescence is strictly equivalent to complement fixation as assessed by standard serological methods. This technique has been applied to the detection of in vivo bound complement in pathological human tissues. It was found that in vivo complement binding occurs in the lesions of several human diseases, but not elsewhere in the same tissues. In a rather limited survey of diseases that has been carried out, in vivo complement binding was found particularly in systemic L.E., various nephritides, and amyloidosis, as well as in single cases of some other diseases. The spectrum of in vivo complement binding has been compared with that of γ-globulin binding (7S and 19S types) and with the demonstration of in vitro complement fixation and rheumatoid factor fixation. It was distinct from each of these. Rheumatoid factor fixation, detected by anti-19S antiserum showed promise as a method for the detection of antigen-antibody complexes and aggregated γ-globulin in tissue sections. The interpretation of these findings in regard to the nature of the binding sites, and their possible significance in regard to pathogenic mechanisms have been discussed.

Platelet Fc Receptor as a Mechanism for Ag-Ab Complex-induced Platelet Injury

1973 ◽  
Vol 29 (02) ◽  
pp. 434-444 ◽  
Author(s):  
E.D Israels ◽  
G Nisli ◽  
F Paraskevas ◽  
L.G Israels
Keyword(s):  
Platelet Aggregation ◽  
Immune Complexes ◽  
Test System ◽  
Fc Receptor ◽  
Rabbit Platelet ◽  
Immune Adherence ◽  
Platelet Receptor ◽  
Antigen Antibody

SummaryAntigen-antibody complexes immunologically unrelated to platelet antigens may produce thrombocytopenia in vivo and platelet aggregation and release in vitro. An in vitro platelet system (rabbit and human) was used to study the platelet receptor that mediates the attachment of the immune complex. Platelet aggregation induced by 7 S immune complexes or aggregated gammaglobulin was blocked by prior exposure of the platelet to isolated antibody Fc. Fab from the same antibody was not inhibitory. 5S complexes lacking the Fc piece did not produce aggregation. Serum, as a source of complement was included in the rabbit platelet test system. However, the role of complement is thought to be secondary as it did not bind to platelets in the absence of 7 S complexes and was fixed only secondarily to 7 S binding. On the basis of these studies it is suggested that the platelet membrane contains an Fc receptor and that the primary fixing of immune complexes to the platelet is through the antibody Fc rather than by complement mediated non-specific immune adherence. Antibody Fc fixation to the Fc receptor site of the platelet is probably the common pathway for platelet injury induced by a number of antigen-antibody complexes immunologically unrelated to the platelet.

scholarly journals A potential role for the COOH-terminal domain in the lateral packing of type III intermediate filaments.

1991 ◽  
Vol 114 (4) ◽  
pp. 773-786 ◽  
Author(s):  
P D Kouklis ◽  
T Papamarcaki ◽  
A Merdes ◽  
S D Georgatos
Keyword(s):  
Potential Role ◽  
Type Iii ◽  
Filament Assembly ◽  
Filament Bundles ◽  
Self Association ◽  
Specific Association ◽  
A Site ◽  
Idiotypic Antibody

To identify sites of self-association in type III intermediate filament (IF) proteins, we have taken an "anti-idiotypic antibody" approach. A mAb (anti-Ct), recognizing a similar feature near the end of the rod domain of vimentin, desmin, and peripherin (epsilon site or epsilon epitope), was characterized. Anti-idiotypic antibodies, generated by immunizing rabbits with purified anti-Ct, recognize a site (presumably "complementary" to the epsilon epitope) common among vimentin, desmin, and peripherin (beta site or beta epitope). The beta epitope is represented in a synthetic peptide (PII) modeled after the 30 COOH-terminal residues of peripherin, as seen by comparative immunoblotting assays. Consistent with the idea of an association between the epsilon and the beta site, PII binds in vitro to intact IF proteins and fragments containing the epsilon epitope, but not to IF proteins that do not react with anti-Ct. Microinjection experiments conducted in vivo and filament reconstitution assays carried out in vitro further demonstrate that "uncoupling" of this site-specific association (by competition with PII or anti-Ct) interferes with normal IF architecture, resulting in the formation of filaments and filament bundles with diameters much greater than that of the normal IFs. These thick fibers are very similar to the ones observed previously when a derivative of desmin missing 27 COOH-terminal residues was assembled in vitro (Kaufmann, E., K. Weber, and N. Geisler. 1985. J. Mol. Biol. 185:733-742). As a molecular explanation, we propose here that the epsilon and the beta sites of type III IF proteins are "complementary" and associate during filament assembly. As a result of this association, we further postulate the formation of a surface-exposed "loop" or "hairpin" structure that may sterically prevent inappropriate filament-filament aggregation and regulate filament thickness.

scholarly journals In vitro processing at the 3'-terminal region of pre-18S rRNA by a nucleolar endoribonuclease.

1990 ◽  
Vol 10 (8) ◽  
pp. 3868-3872 ◽  
Author(s):  
C M Shumard ◽  
C Torres ◽  
D C Eichler
Keyword(s):  
18S Rrna ◽  
Precise Determination ◽  
In Vivo Studies ◽  
Rrna Sequence ◽  
S1 Nuclease ◽  
In Vitro Processing ◽  
Rrna Maturation ◽  
A Site

In an investigation of the possible involvement of a highly purified nucleolar endoribonuclease in processing of pre-rRNA at the 3' end of the 18S rRNA sequence, an in vitro synthesized pre-18S rRNA transcript containing the 3' end region of 18S rRNA and the 5' region of the first internal transcribed spacer (ITS1) was used as a substrate for the enzyme. Cleavages generated by the nucleolar RNase were localized by S1 nuclease protection analysis and by the direct release of labeled rRNA products. Precise determination of the specificity of cleavage was achieved by RNA sequence analysis with end-labeled rRNA transcripts. These data demonstrated that the purified nucleolar RNase cleaved the pre-18S rRNA transcript at three specific sites relative to the 3' region of 18S rRNA. The first two sites included the mature 3'-end 18S rRNA sequence and a site approximately 55 nucleotides downstream of the 3'-end 18S rRNA sequence, both of which corresponded directly to recent results (Raziuddin, R. D. Little, T. Labella, and D. Schlessinger, Mol. Cell. Biol. 9:1667-1671, 1989) obtained with transfected mouse rDNA in hamster cells. The other cleavage occurred approximately 35 nucleotides upstream from the mature 3' end in the 18S rRNA sequence. The results from this study mimic the results obtained from in vivo studies for processing in the 3' region of pre-18S rRNA, supporting the proposed involvement of this nucleolar endoribonuclease in rRNA maturation.

Detection of Circulating Immune Complexes in the Sera of Rabbits with Experimental Syphilis: Possible Role in Immunoregulation

1980 ◽  
Vol 29 (2) ◽  
pp. 575-582
Author(s):  
Robert E. Baughn ◽  
Kenneth S. K. Tung ◽  
Daniel M. Musher
Keyword(s):  
Immune Complexes ◽  
Proteolytic Enzymes ◽  
Suppressor Cell ◽  
Suppressive Effect ◽  
Circulating Immune Complexes ◽  
Time Period ◽  
Infected Cells ◽  
Disseminated Disease

The in vivo and in vitro immunoglobulin G plaque-forming cell responses to sheep erythrocytes (SRBC) are nearly obliterated during disseminated syphilitic infection (3 to 8 weeks post-intravenous injection) in rabbits. Splenic and lymph node cells obtained from infected rabbits during this time period were capable of suppressing the normal in vitro responses of uninfected, SRBC-primed cells. Cell-free washings of cells from infected animals were also suppressive. This finding coupled with the fact that treatment of infected cells with proteolytic enzymes abrogated the suppressive effect constitute arguments against involvement of a specific suppressor cell population. The incidence of elevated levels of circulating immune complexes in the sera of rabbits with disseminated disease was also significantly different from that of uninfected controls or infected rabbits before the onset or after the regression of lesions. When added to cultures of lymphocytes from uninfected, SRBC-sensitized rabbits, sera containing complexes caused dose-related suppression of the in vitro immunoglobulin responses. Unlike immune complexes, no correlation was found between the presence of mucopolysaccharide materials and the stage of infection or the ability of serum to suppress the immunoglobulin responses to SRBC.

Preparative enrichment of human tissue cells capable to change a site of growth in vitro or in vivo - Recent developments

2018 ◽  
Vol 48 (10) ◽  
pp. 954-960 ◽  
Author(s):  
Johann Bauer ◽  
Hari H. P. Cohly ◽  
Jayashree Sahana ◽  
Daniela Grimm
Keyword(s):  
Human Tissue ◽  
Recent Developments ◽  
Tissue Cells ◽  
A Site

scholarly journals The Escherichia coli cysG promoter belongs to the ‘extended −10’ class of bacterial promoters

1993 ◽  
Vol 296 (3) ◽  
pp. 851-857 ◽  
Author(s):  
T Belyaeva ◽  
L Griffiths ◽  
S Minchin ◽  
J Cole ◽  
S Busby
Keyword(s):  
Escherichia Coli ◽  
Point Mutations ◽  
Growth Conditions ◽  
Upstream Region ◽  
E Coli ◽  
Run Off ◽  
A Site ◽  
Specific Sequences

The Escherichia coli cysG promoter has been subcloned and shown to function constitutively in a range of different growth conditions. Point mutations identify the -10 hexamer and an important 5′-TGN-3′ motif immediately upstream. The effects of different deletions suggest that specific sequences in the -35 region are not essential for the activity of this promoter in vivo. This conclusion was confirmed by in vitro run-off transcription assays. The DNAase I footprint of RNA polymerase at the cysG promoter reveals extended protection upstream of the transcript start, and studies with potassium permanganate as a probe suggest that the upstream region is distorted in open complexes. Taken together, the results show that the cysG promoter belongs to the ‘extended -10’ class of promoters, and the base sequence is similar to that of the P1 promoter of the E. coli galactose operon, another promoter in this class. In vivo, messenger initiated at the cysG promoter appears to be processed by cleavage at a site 41 bases downstream from the transcript start point.

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