Reactivity of the18 Neutralizing HmAbs with SARS CoV 12-510-S1 proteins.

<p>Medisorp ELISA plates were coated with 100 ng/well of Urbani and RBD mutant 12-510S1-IgG proteins and 2.5 µg/ml of each HmAb was used as the primary antibody. Anti-human IgG2 HRP mouse monoclonal antibody was used as secondary antibody. OD was measured at 450 nm. Error bars represent SD of a representative experiment performed in triplicates. (A) Urbani versus Sin845 mutant. (B) Urbani versus GD01 mutant. (C) Urbani versus GZ0402 mutant. (D) Urbani versus GZ-C mutant.</p

<i>In vitro</i> pseudovirus neutralization assay.

<p>Eighteen neutralizing HmAbs were tested against different mutant as well as Urbani pseudoviruses. Pseudoviruses equivalent to 10 ng of HIVp24 were incubated for 1 hr with 25 µg/ml of each of the HmAbs at 37°C. The virus/Ab mixtures were then added to 293/ACE2 stable cell line. Seventy two hours later, the virus entry was determined by luciferase expression. The percentage entry inhibitions obtained with Abs were calculated and normalized to HIV/Urbani-S inhibitions (A) HIV/GZ-C and HIV/Sin845 inhibitions (B) HIV/GZ0402 and HIV/GD01 inhibitions. Polyclonal rabbit immune serum (PolyAb) was used as a positive control. Error bars represent SD of a representative experiment performed in triplicates.</p

Combinations of HmAbs more efficiently inhibit the entry of SARS-CoV RBD surrogate clinical isolates.

<p>Neutralizing HmAbs binding to different regions of S protein 4D4 (S1), 1F8 (HR1), 5E9 (HR2)) were tested for their ability to neutralize pseudoviruses in different combinations as well as individually at a concentration of 6.25 µg/ml each. The virus/Ab mixture was incubated for 1 hr at 37°C then added to 293/ACE2 stable cell line. Seventy two hours later, the virus entry was determined by luciferase expression. The percentage entry inhibitions by individual antibodies as well as combinations of antibodies were calculated. Error bars represent SD of representative experiment performed in triplicates. Statistical analysis was done using Student-t test, significant differences are indicated by asterisks,<i>* p<0.05.</i></p

HmAbs to HR1 and HR2 can efficiently neutralize surrogate clinical isolates.

a<p>Likely binding region of antibodies.</p>b<p>S glycoprotein ectodomain.</p>c<p>Anti-SARS-S protein polyclonal antibody.</p

Reactivity of Urbani SARS-CoV-S protein antibodies with Urbani S1 protein and mutant S1 proteins.

<p>(A) Different dilutions of a rabbit anti-Urbani SARS-CoV-S protein immune serum were tested in an ELISA against Urbani as well as mutant S1-IgG proteins. Anti-rabbit donkey polyclonal HRP antibody was used as the secondary antibody. (B) Competitive ELISA assay: Different protein concentrations of Urbani or GZ-C proteins were pre-incubated with 5A7 antibody then the protein/Ab mixtures were tested for binding to the other protein by ELISA. OD was measured at 450 nm.</p

Age-dependent divergent effects of OX40L treatment on the development of diabetes in NOD mice

<p>Earlier, we have shown that GM-CSF derived bone marrow (BM) dendritic cells (G-BMDCs) can expand Foxp3⁺ regulatory T-cells (Tregs) through a TCR-independent, but IL-2 dependent mechanism that required OX40L/OX40 interaction. While some reports have shown suppression of autoimmunity upon treatment with an OX40 agonist, others have shown exacerbation of autoimmune disease instead. To better understand the basis for these differing outcomes, we compared the effects of OX40L treatment in 6-week-old pre-diabetic and 12-week-old near diabetic NOD mice. Upon treatment with OX40L, 6-week-old NOD mice remained normoglycemic and showed a significant increase in Tregs in their spleen and lymph nodes, while 12-week-old NOD mice very rapidly developed hyperglycemia and failed to show Treg increase in spleen or LN. Interestingly, OX40L treatment increased Tregs in the thymus of both age groups. However, it induced Foxp3⁺CD103⁺CD38⁻ stable-phenotype Tregs in the thymus and reduced the frequency of autoreactive Teff cells in 6-week-old mice; while it induced Foxp3⁺CD103⁻CD38⁺ labile-phenotype Tregs in the thymus and increased autoreactive CD4⁺ T cells in the periphery of 12-week-old mice. This increase in autoreactive CD4⁺ T cells was likely due to either a poor suppressive function or conversion of labile Tregs into Teff cells. Using <i>ex vivo</i> cultures, we found that the reduction in Treg numbers in 12-week-old mice was likely due to IL-2 deficit, and their numbers could be increased upon addition of exogenous IL-2. The observed divergent effects of OX40L treatment were likely due to differences in the ability of 6- and 12-week-old NOD mice to produce IL-2.</p