The Inducible Defense System: Antibody Molecules and Antigen-Antibody Reactions
Julius P. Kreier in Infection, Resistance, and Immunity, 2022
The classical example of an agglutination assay is the direct hemagglutination assay (Figure 7.16). In order to determine if a person has antibodies to antigens expressed on the surface of another person′s erythrocytes, various dilutions of serum from the person are added to wells of a microtiter plate. Then, a suspension of the erythrocytes to be tested is added. If antibodies are present in sufficient concentration to cross-link the erythrocytes, the immune complex, which forms, precipitates as a fluffy layer on the bottom of the well. If antibodies are not present, the erythrocytes roll down the sides of the well, and a compact pellet of cells forms at the center of the well, in the example shown, a positive reaction is seen with serum diluted 1:20,1:40 and 1:80, but not 1:160. The term titer is used to refer to the reciprocal of the highest dilution that gives a positive reaction. Thus, we would say that the serum used in the test had a titer of 1:80.
The Lymphatic/Immune System and Its Disorders
Walter F. Stanaszek, Mary J. Stanaszek, Robert J. Holt, Steven Strauss in Understanding Medical Terms, 2020
Immune reactions play a vital role in a number of diagnostic tests. Several infections, including HIV, hepatitis B, and Cytomegalovirus (CMV), are identified by detecting antibodies in the blood. The complement fixation (CF) test is used in the diagnosis of viral diseases by detecting specific antibodies in the patient's serum. The presence of antibodies is assumed to be indicative of infection, and antibody titer (concentration) indicates degree of response or whether the infection is active. Antibodies are detected with immunofluorescence, enzyme-linkedimmunosorbent assay (ELISA), agglutination tests, and iontophoresis. Without the immune response, there would be no antibodies to detect.
Drug Repurposing and Novel Antiviral Drugs for COVID-19 Management
Debmalya Barh, Kenneth Lundstrom in COVID-19, 2022
Convalescent plasma contains antibody-rich plasma products collected from eligible donors, who have recovered from COVID-19. In a US-based retrospective study of anti-SARS-CoV-2 IgG antibody levels in convalescent plasma and their effect in the treatment of hospitalized adults with COVID-19 was determined. The primary outcome was death within 30 days after plasma transfusion. Among patients hospitalized with COVID-19 who did not receive mechanical ventilation, transfusion of plasma with higher anti-SARS-CoV-2 IgG antibody titers was associated with a lower risk of death than transfusion of plasma with lower antibody levels. Among 3,082 patients in the analysis, death within 30 days occurred in 115 of 515 patients (22.3%) in the high-titer group, 549 of 2,006 patients (27.4%) in the medium-titer group, and 166 of 561 patients (29.6%) in the low-titer group. High plasma titer was defined as 250 or greater in the Broad Institute’s neutralizing antibody assay or an S/C cut-off of 12 or higher in the Ortho VITROS IgG assay [42]. The FDA granted EUA on August 23, 2020, for use of convalescent plasma in hospitalized patients with COVID-19 [43].
Rabbits transgenic for human IgG genes recapitulating rabbit B-cell biology to generate human antibodies of high specificity and affinity
Published in mAbs, 2020
Francesca Ros, Sonja Offner, Stefan Klostermann, Irmgard Thorey, Helmut Niersbach, Sebastian Breuer, Grit Zarnt, Stefan Lorenz, Juergen Puels, Basile Siewe, Nicole Schueler, Tajana Dragicevic, Dominique Ostler, Imke Hansen-Wester, Valeria Lifke, Brigitte Kaluza, Klaus Kaluza, Wim van Schooten, Roland Buelow, Alain C Tissot, Josef Platzer
Antibodies, reagents, and conditions used for ELISA IgM and IgG serum analytics are described in Supplementary material, Part 6, Table 9. For antigen-specific serum titers analysis, human BMP9 pro-domain was immobilized on a 96-well NUNC Maxisorp plate at 2.5 µg/ml. Antisera, were serially diluted in 0.5% Crotein C in Phosphate-buffered Saline (PBS), 100 µl/well; detection was performed with one of the following reagents: 1) horseradish peroxidase (HRP)-conjugated donkey anti-rabbit IgG antibody (Jackson ImmunoResearch/Dianova 711–036-152; 1/16 000); 2) HRP-conjugated rabbit anti-human IgG antibody (Pierce/Thermo Scientific 31423; 1/5000); or 3) biotinylated goat anti-human kappa antibody (Southern Biotech/Biozol 2063–08, 1/5 000) and streptavidin-HRP, each diluted in 0.5% Crotein C in PBS, 100 µl/well. Titer was defined as dilution of antisera resulting in half-maximal signal.
A natively paired antibody library yields drug leads with higher sensitivity and specificity than a randomly paired antibody library
Published in mAbs, 2018
Adam S. Adler, Daniel Bedinger, Matthew S. Adams, Michael A. Asensio, Robert C. Edgar, Renee Leong, Jackson Leong, Rena A. Mizrahi, Matthew J. Spindler, Srinivasa Rao Bandi, Haichun Huang, Pallavi Tawde, Peter Brams, David S. Johnson
All mouse work was overseen by a licensed veterinarian. Six Medarex (BMS) Human Ig transgenic mice were immunized with recombinant IL-21R-ECD-TVMV-His protein (amino acids 1–232 expressed in 293–6E cells and purified using Ni column followed by 26/60 Superdex 200 column), using Ribi (Sigma) as an adjuvant. The immunogen (7.5 μg) was injected into each footpad every 7 days for 33 days. Titer was assessed by ELISA on a 1:2 dilution series of each animal's serum, starting at a 1:50 dilution. A final tail boost of 10 μg without adjuvant was given to each animal before harvest. Lymph nodes (popliteal, inguinal, axillary, and mesenteric) were surgically removed after sacrifice. Single cell suspensions for each animal were made by manual disruption followed by passage through a 40 μM filter, and then combined into a single pool of cells.
Immunology of HPV-mediated cervical cancer: current understanding
Published in International Reviews of Immunology, 2021
Babban Jee, Renu Yadav, Sangeeta Pankaj, Shivendra Kumar Shahi
The recombinant HPV vaccines are highly immunogenic, eliciting much stronger antibody response (IgG) in the vaccinated subjects than natural infection [194]. The serum antibody titer was high for at least (i) 10 years in the people vaccinated with bivalent vaccine [195,196], (ii) 9.9 years in the quadravalent vaccinated people [197,198] and (iii) 5 years in the people immunized with nonavalent vaccine [199]. Although, lower titers of vaccine induced- HPV-specific antibodies were also detected in cervicovaginal secretions (CVS), indicating the exudation/transudation of systemic antibody to the cervical mucosa in order to prevent HPV infection and to stop its spread [200]. Due to long term presence of HPV-specific antibody response in serum, the HPV vaccine appears to provide high level of protection against HPV infection and pre-malignant neoplasias [5]. Studies also suggest that HPV vaccine may be concomitantly administered with other vaccines such as diphtheria, tetanus and acellular pertussis (TDAP) vaccine, hepatitis A vaccine, hepatitis B vaccine, combined hepatitis A and B vaccine, inactivated poliovirus vaccine and meningococcal vaccine [201].
Related Knowledge Centers
- Antibody
- Coombs Test
- Elisa
- Hemagglutination
- Titration
- Epitope
- Serial Dilution
- Gold
- Silver
- Serum