Immunologic tolerance in adult animals to protein antigens treated by biological filtration

1969 ◽  
Vol 68 (5) ◽  
pp. 1260-1262
Author(s):  
G. N. Obrezha
Author(s):  
R. G. Painter ◽  
K. T. Tokuyasu ◽  
S. J. Singer

A technique for localizing intracellular antigens with immunoferritin conjugates directly on ultrathin frozen sections of glutaraldehyde-fixed tissues has been developed. This method overcomes some of the limitations of previously described procedures, since it avoids drastic fixation, dehydration and embedding procedures which could denature many protein antigens.Briefly cells or tissues were fixed with glutaraldehyde (0.5 to 2% for 1 hr), and ultrathin frozen sections were cut and mounted on grids covered with carbon-coated Formvar film by the procedure described previously. Such sections were stained with ferritin-antibody conjugates by methods described elsewhere.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Francesca Mancini ◽  
Gianmarco Gasperini ◽  
Omar Rossi ◽  
Maria Grazia Aruta ◽  
Maria Michelina Raso ◽  
...  

AbstractGMMA are exosomes released from engineered Gram-negative bacteria resembling the composition of outer membranes. We applied the GMMA technology for the development of an O-Antigen (OAg) based vaccine against Shigella sonnei, the most epidemiologically relevant cause of shigellosis. S. sonnei OAg has been identified as a key antigen for protective immunity, and GMMA are able to induce anti-OAg-specific IgG response in animal models and healthy adults. The contribution of protein-specific antibodies induced upon vaccination with GMMA has never been fully elucidated. Anti-protein antibodies are induced in mice upon immunization with either OAg-negative and OAg-positive GMMA. Here we demonstrated that OAg chains shield the bacteria from anti-protein antibody binding and therefore anti-OAg antibodies were the main drivers of bactericidal activity against OAg-positive bacteria. Interestingly, antibodies that are not targeting the OAg are functional against OAg-negative bacteria. The immunodominant protein antigens were identified by proteomic analysis. Our study confirms a critical role of the OAg on the immune response induced by S. sonnei GMMA. However, little is known about OAg length and density regulation during infection and, therefore, protein exposure. Hence, the presence of protein antigens on S. sonnei GMMA represents an added value for GMMA vaccines compared to other OAg-based formulations.


1985 ◽  
Vol 40 (7-8) ◽  
pp. 539-550 ◽  
Author(s):  
Margarete Borg

Abstract The labeling of immunocomplexes for scanning electron microscopy (SEM) is a fairly new technique, and the various procedures, that have been proposed, have not yet been compared. Such comparative evaluation was performed with Candida protease as a target antigen. This secretory enzyme of the opportunistic yeast Candida albicans can be localized on the surface of fungal blastopores and mycelia, both after growth in proteinaceous medium and upon infection of murine peritoneal macrophages. The presence of the protease antigen was confirmed by immunofluorescence and by immunoperoxidase-light microscopy. The decoration of protease - anti protease complexes for SEM was attempted with colloids derived from the immunoperoxidase reaction, by the immunogold technique, and by antibodies linked to beads of synthetic polymers (polystyrene, polymethacrylate, polyacrolein). In addition, inactivated Staphylococcus aureus was used, which binds to antibodies through its protein-A. The high resolution by SEM of surface structures was matched only by the colloid based decoration techniques. All conjugates with beads suffered from inconsistent binding, which did not correspond with the distribution of the surface antigen. The comparatively best result with beads was obtained with polystyrene (Latex). Colloid based techniques in addition allow for critical point drying, which cannot be applied to synthetic beads in the usual manner.


1964 ◽  
Vol 120 (3) ◽  
pp. 435-447 ◽  
Author(s):  
Marianne M. Dorner ◽  
Jonathan W. Uhr

Specific immunologic tolerance to bovine serum albumin (BSA) was induced in approximately one-half of the rabbits that had been primarily immunized and were prepared for a secondary antibody response to BSA. The state of tolerance lasted for several months in the majority of rabbits and was not easily terminated by immunization with human serum albumin followed by BSA.


2018 ◽  
Vol 1 ◽  
pp. 251522111878837 ◽  
Author(s):  
Mukesh Kumar Sinha ◽  
Biswa Ranjan Das

Chitosan derivatives are difficult to electrospun because they have poor flexibility of their polyelectrolyte chains. Based on extensive trails, we have successfully electrospun chitosan polymer and, subsequently, coated on non-woven polypropylene utilizing Nanospider technology. This experimentally developed nanofibrous webs of various densities were coated on non-woven fabric and, subsequently, stitched with activated carbon sphere (ACS) adhered composite fabric. Biological filtration and chemical protection were evaluated and the optimized density offering the highest value with meeting specified comfort was assessed. Results showed that optimized web morphology of 0.43 g m−2 is the best for integration with nuclear, biological and chemical absorbent layer of low ACS add-on in all aspects of comfort and protective behaviours. This will be meeting stringent defence protective requirements and lowering down the weight of suit by approximately 25%. An attempt has also been made in this research to protect from sulphur mustard chemical warfare agent by using both theories: (a) barrier techniques and (b) disintegrating the trapped molecules via functionalization of the web. Result shows that first molecules get trapped by in web layer (barrier effect) and subsequently destroyed by hydrolysis mechanism. Scanning microscopic image shows web is acting as barrier layer by trapping sulphur mustard particles. Optimized web of 0.43 g m−2 was functionalized with zinc (Zn) oxide and the presence of Zn particles was confirmed by imaging techniques. Crystalline and thermal analysis depicts that structural changes were found in sulphur mustard spotted functionalized web. Raman spectra show chemically disintegrated hydrolysed products of sulphur mustard. Bacterial filtration efficiency, antimicrobial and comfort properties were measured for assessing the introduction of nanowebs for biological protection and chemical protection in newly created multilayered fabric structure with low ACS add-on (180 g m−2). The initial encouraging outcome of this research expects whether the multilayered fabric could be introduced in the suit.


1987 ◽  
Vol 182 (4) ◽  
pp. 343-348
Author(s):  
G.A. King ◽  
J.K. Heyes
Keyword(s):  

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