Journal: Journal of Clinical Microbiology
Article Title: SARS-CoV-2 Assays To Detect Functional Antibody Responses That Block ACE2 Recognition in Vaccinated Animals and Infected Patients
doi: 10.1128/JCM.01533-20
Figure Lengend Snippet: Animal IgG and serological competition. (A) IgG and serological competition schematic. Anti-His pAb captures SARS-CoV-2 spike protein. Immunized sera or IgG from small animals are used as competitors to block ACE2-IgHu receptor binding when premixed. ACE2-IgHu remaining is determined from an anti-human-HRP colorimetric readout. (B) IgGs present in a vaccinated BALB/c mouse block ACE2-IgHu binding with greater effect when the full-length SARS-CoV-2 S1-S2 spike protein is immobilized versus the S1 subunit by itself. (C) Area under the concentration-time curve (AUC) schematic displaying the larger area for uninhibited ACE2 binding versus the area from curves showing competition with ACE2. (D) AUC of IgGs purified from immunized rabbit sera (IgGr low dose, blue; IgGr high dose, red) versus naive IgGr or day 0 IgGr. (E) AUC of sera from immunized rabbits (low dose rabbit sera, blue; high dose rabbit sera, red) versus naive rabbit sera or day 0 rabbit sera. (F) AUC of sera from immunized guinea pigs at week 2 (dark blue) and individual animals (blue), naive sera (gray), and pooled day 0 sera from all animals (black). The pooled immunized curve displayed a comparable AUC to the average AUC from all individual immunized animals.
Article Snippet: DNA encoding the IgG1 human Fc sequence was added to the C terminus of the huACE2 and cloned by Twist Bioscience into a modified mammalian pVax-1 expression plasmid to generate the recombinant plasmid ACE2-IgHu.
Techniques: Blocking Assay, Binding Assay, Concentration Assay, Purification