scholarly journals Immunogenicity of liposome-bound hyaluronate in mice. At least two different antigenic sites on hyaluronate are identified by mouse monoclonal antibodies.

1988 ◽  
Vol 168 (3) ◽  
pp. 971-982 ◽  
Author(s):  
H M Fillit ◽  
M Blake ◽  
C MacDonald ◽  
M McCarty
Keyword(s):  
Ascorbic Acid ◽  
Heparan Sulfate ◽  
Acid Treatment ◽  
Glucuronic Acid ◽  
Antigenic Site ◽  
Electrostatic Forces ◽  
Igg Antibody ◽  
Antigenic Sites ◽  
Mode Of Presentation ◽  
Phosphorylated Compounds

Hyaluronate (HA) was previously demonstrated to be immunogenic in rabbits. The immunogenicity of HA in mice was studied. Hyaluronidase-digested streptococcal HA (IA1) covalently linked to liposomes (IA1-liposomes) were produced for immunization. Mice immunized with IA1-liposomes developed measurable serum antibodies to IA1, while mice immunized with IA1 in Freund's adjuvant did not. mAbs produced by two stable hybridomas (10G6 and 5F11) from mice immunized with IA1-liposomes produced IgG antibody reactive with HA in ELISA. 10G6 had a much higher avidity for liposome-bound IA1 than free IA1, while 5F11 did not, suggesting that the mode of presentation of IA1 is important in HA immunogenicity and antigenicity. Both mAbs recognized terminal HA immunodeterminants exposed by hyaluronidase treatment. Sonication had no effect on HA reactivity for either mAb. However, ascorbic acid treatment significantly reduced the antigenicity of HA for mAb 5F11, but not 10G6. Only 10G6 was inhibited by glucuronic acid. Electrostatic forces appear to play a role in the binding site of 5F11, but not 10G6. 5F11 crossreacts with heparan sulfate and phosphorylcholine, while 10G6 did not crossreact with any glycosaminoglycans or phosphorylated compounds tested. These results confirm that HA is immunogenic. They suggest that the mode of presentation of HA is important for the induction of the immune response, and in HA antigenicity. At least two different antigenic sites on HA were demonstrated. 10G6 recognizes a terminal HA antigenic site expressed on IA1-liposomes that contains glucuronic acid in its immunodominant site. 5F11 recognizes an HA antigenic site in which electrostatic forces appear to play a role, is sensitive to ascorbic acid treatment, and is crossreactive with heparan sulfate. The use of mAbs should facilitate immunologic studies of HA.

scholarly journals Monoclonal antibodies prepared against Dictyostelium actin: characterization and interactions with actin.

1984 ◽  
Vol 99 (1) ◽  
pp. 287-295 ◽  
Author(s):  
P A Simpson ◽  
J A Spudich ◽  
P Parham
Keyword(s):  
Monoclonal Antibodies ◽  
Antigenic Site ◽  
Amino Acid Sequences ◽  
Cellular Slime Mold ◽  
Antigenic Sites ◽  
Critical Residue ◽  
Slime Mold Dictyostelium Discoideum ◽  
Cellular Slime ◽  
B Lymphoid ◽  
Alpha Actins

Three mouse monoclonal antibodies, Act I, Act II, and Act IV, against actin from the cellular slime mold Dictyostelium discoideum, have been made and characterized. All three antibodies are IgG1 and share the following properties: They form stable complexes with monomeric Dictyostelium actin, which prevents polymerization of the actin into filaments. On addition to preformed actin filaments, they cause a reduction in filament size and in the viscosity of the actin solution. They cross-react strongly with actins from the lower eucaryotes Physarum and Acanthamoeba, but not with alpha-actins from rabbit and human muscle or beta- and gamma-actins from human erythrocytes and a human B lymphoid cell line. Act II and Act IV recognize a similar antigenic determinant that is topographically distinct from that identified by Act I. In protein immunoblotting, only Act I bound strongly to Dictyostelium actin. Analysis of actin fragments with this technique showed that amino acids 13 to about 50 are required for Act I binding to actin. A comparison of the amino acid sequences of actins from lower eucaryotes and higher vertebrates implicates threonine 41 as a critical residue in the Act I antigenic site. The properties of Act II and Act IV suggest that they recognize antigenic sites involving the NH2-terminal six residues.

scholarly journals Effect of the ascorbic acid treatment on the NADHd-positive myenteric neurons of diabetic rats proximal colon

2007 ◽  
Vol 50 (1) ◽  
pp. 31-38 ◽  
Author(s):  
Jacqueline Nelisis Zanoni ◽  
Renata Virginia Fernandes Pereira ◽  
Priscila de Freitas
Keyword(s):  
Ascorbic Acid ◽  
Acid Treatment ◽  
Neuroprotective Effect ◽  
Proximal Colon ◽  
Diabetic Rats ◽  
Daily Treatment ◽  
Body Area ◽  
Neuronal Density ◽  
Myenteric Neurons ◽  
Intestinal Segments

The aim of this work was to study the effect of the ascorbic acid on the myenteric neurons of diabetic rats proximal colon. Fifteen rats (90 days old) were divided into three groups: control, untreated diabetic and treated diabetic with ascorbic acid (DA). After 120 days of daily treatment with ascorbic acid, the intestinal segments were submitted to the NADH-diaphorase (NADHd) histochemistry technique to expose the myenteric neurons. The group DA showed a higher neuronal density (33.4 %) when compared to the untreated diabetic animals (p < 0.05). Cellular body area of neurons was significantly larger in group DA (17.3 %) when compared to the untreated diabetics (p < 0.05). It could be concluded that the ascorbic acid promoted a neuroprotective effect on the NADHd myenteric neurons of the proximal colon of diabetic rats.

scholarly journals Epitope-Specific Serological Assays for RSV: Conformation Matters

Vaccines ◽  
2019 ◽  
Vol 7 (1) ◽  
pp. 23 ◽  
Author(s):  
Emily Phung ◽  
Lauren Chang ◽  
Kaitlyn Morabito ◽  
Masaru Kanekiyo ◽  
Man Chen ◽  
...  
Keyword(s):  
Neutralizing Antibodies ◽  
Antigenic Site ◽  
Immune Monitoring ◽  
Effective Vaccine ◽  
F Protein ◽  
Correlates Of Protection ◽  
Vaccine Trials ◽  
Antigenic Sites ◽  
Syncytial Virus ◽  
The Impact

Respiratory syncytial virus (RSV) causes substantial morbidity and mortality in children and older adults. An effective vaccine must elicit neutralizing antibodies targeting the RSV fusion (F) protein, which exists in two major conformations, pre-fusion (pre-F) and post-fusion (post-F). Although 50% of the surface is shared, pre-F contains highly neutralization-sensitive antigenic sites not present on post-F. Recent advancement of several subunit F-based vaccine trials has spurred interest in quantifying and understanding the protective potential of antibodies directed to individual antigenic sites. Monoclonal antibody competition ELISAs are being used to measure these endpoints, but the impact of F conformation and competition from antibodies binding to adjacent antigenic sites has not been thoroughly investigated. Since this information is critical for interpreting clinical trial outcomes and defining serological correlates of protection, we optimized assays to evaluate D25-competing antibodies (DCA) to antigenic site Ø on pre-F, and compared readouts of palivizumab-competing antibodies (PCA) to site II on both pre-F and post-F. We show that antibodies to adjacent antigenic sites can contribute to DCA and PCA readouts, and that cross-competition from non-targeted sites is especially confounding when PCA is measured using a post-F substrate. While measuring DCA and PCA levels may be useful to delineate the role of antibodies targeting the apex and side of the F protein, respectively, the assay limitations and caveats should be considered when conducting immune monitoring during vaccine trials and defining correlates of protection.

scholarly journals Antigenic and genetic analysis of equine influenza viruses from tropical Africa in 1991

1996 ◽  
Vol 117 (2) ◽  
pp. 367-374 ◽  
Author(s):  
C. A. O. Adeyefa ◽  
M. L. James ◽  
J. W. McCauley
Keyword(s):  
Amino Acid ◽  
Nucleotide Sequence ◽  
Antigenic Site ◽  
Glycosylation Site ◽  
Influenza Viruses ◽  
Amino Acid Substitutions ◽  
Antigenic Analysis ◽  
Equine Influenza ◽  
Antigenic Sites ◽  
European Strain

SummaryA detailed analysis of equine (H3N8) influenza viruses isolated in Nigeria during early 1991 has been undertaken. Antigenic analysis and the complete nucleotide sequence of the HA gene of three Nigerian equine influenza viruses A/eq/Ibadan/4/91, A/eq/Ibadan/6/91 and A/eq/Ibadan/9/91 are presented and limited sequence analysis of each of the genes encoding the internal polypeptides of the virus has been carried out. These results establish that, despite the geographical location from which these viruses were isolated, two were similar to the viruses which were concurrently causing disease in Europe in 1989 and 1991 and were related to viruses that have been predominating in horses since 1985. The third was more closely related to viruses isolated from 1991 onward in Europe but also in other parts of the globe. A comparison of the nucleotide sequence of two of the viruses isolated in Nigeria (A/eq/Ibadan/4/91 and A/eq/Ibadan/6/91) with a European strain (A/eq/Suffolk/89) showed limited variation in the haemagglutinin gene which caused amino acid substitutions in one of the antigenic sites: this mutation resulted in the potential production of a new glycosylation site in antigenic site A. The other Nigerian virus (A/eq/Ibadan/9/91) showed only a single one amino acid change from another European strain (A/eq/Arundel/12369/91). The two distinct Nigerian viruses had several amino acid substitutions in the antigenic sites of the haemagglutinin glycoprotein.

scholarly journals Double immunocytochemical labeling applying the protein A-gold technique.

1982 ◽  
Vol 30 (1) ◽  
pp. 81-85 ◽  
Author(s):  
M Bendayan
Keyword(s):  
Tissue Section ◽  
Protein A ◽  
Antigenic Site ◽  
Acinar Cells ◽  
Pancreatic Acinar Cells ◽  
Secretory Proteins ◽  
Zymogen Granules ◽  
Double Labeling ◽  
Gold Particles ◽  
Antigenic Sites

In the present study we report the modifications and the different steps of the protein A-gold (pAg) technique that allow the simultaneous demonstration of two antigenic sites on the same tissue section. The labeling is carried out in the following manner: face A of the tissue section is incubated with an antiserum followed by a pAg complex prepared with large gold particles; face B of the same tissue section is then incubated with a second antiserum followed by a pAg complex prepared with small gold particles. Each of the pAg complexes reveals a different antigenic site on opposite faces of the tissue section. The transparency of the section in the electron beam allows the visualization of the gold particles present on both faces. The double labeling pAg technique was applied for the simultaneous demonstration of two secretory proteins in the same Golgi, condensing vacuoles, and zymogen granules of the rat pancreatic acinar cells.

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