875 research outputs found
P03-10. Induction of neutralizing antibodies in Rhesus macaques following mucosal challenge with R5 tropic SHIV162P3 isolate
Enhanced Avidity Maturation of Antibody to Human Immunodeficiency Virus Envelope: DNA Vaccination with gp120-C3d Fusion Proteins
DNA vaccination can elicit both humoral and cellular immune responses and can confer protection against several pathogens. However, DNA vaccines expressing the envelope (Env) protein of human immunodeficiency virus (HIV) have been relatively ineffective at generating high titer, long-lasting, neutralizing antibodies in a variety of animal models. In this study, we report that fusion of Env and the complement component, C3d, in a DNA vaccine, enhances the titers of antibody to Env. Plasmids were generated that expressed a secreted form of Env (sgp120) from three isolates of HIV and these same forms fused to three tandem copies of the murine homologue of C3d (sgp120-3C3d). Analyses of titers and avidity maturation of the raised antibody indicated that immunizations with each of the sgp120-3C3d-expressing DNAs accelerated both the onset and the avidity maturation of antibody to Env. Originally published AIDS Research and Human Retroviruses, Vol. 17, No. 9, June 200
P04-11. Prevalence of neutralizing antibody responses in chronic clades A and D human immunodeficiency virus type 1 (HIV-1) infections
P04-12. Characterization of leukopak PBMC phenotypes and biotypes for optimal performance in HIV-1 neutralization assays
Towards a population-based threshold of protection for COVID-19 vaccines
Correlates of protection for COVID-19 vaccines are urgently needed to license additional vaccines. We measured immune responses to four COVID-19 vaccines of proven efficacy using a single serological platform. IgG anti-Spike antibodies were highly correlated with ID50 neutralization in a validated pseudoviral assay and correlated significantly with efficacies for protection against infection with wild-type, alpha and delta variant SARS-CoV-2 virus. The protective threshold for each vaccine was calculated for IgG anti-Spike antibody. The mean protective threshold for all vaccine studies for WT virus was 154 BAU/ml (95 %CI 42β559), and for studies with antibody distributions that enabled precise estimation of thresholds (i.e. leaving out 2-dose mRNA regimens) was 60 BAU/ml (95 %CI 35β102). We propose that the proportion of individuals with responses above the appropriate protective threshold together with the geometric mean concentration can be used in comparative non-inferiority studies with licensed vaccines to ensure that new vaccines will be efficacious
Evidence for immune-mediated reduction of viral replication in Macaca nemestrina mucosally immunized with inactivated SHIV89.6
AbstractAlthough most HIV-1 infections worldwide result from heterosexual transmission, most vaccine candidates have focused on induction of systemic immunity and protection. We hypothesized that combining systemic priming with mucosal boosting would induce mucosal immunity that would protect from intravaginal challenge. Macaques were primed systemically with recombinant vaccinia viruses and boosted mucosally using inactivated SHIV89.6 plus adjuvant. Other animals received protein boosts with adjuvant alone. Priming and boosting induced antiviral IgG and IgA antibodies. Such antibodies were induced to a lesser degree in animals receiving boosts alone. Anti-SHIV T cell responses were induced only in the prime-boost animals. Immunized animals and controls were challenged intravaginally with SHIV89.6 and significant reductions in proviral and viral RNA loads were observed in the prime-boost animals. The boost-only animals did not have significant viral load reductions. These data suggest that cellular immunity was required for protection from intravaginal challenge. This immunization regimen provides a promising lead for vaccine development
P04-23. HIV-1 neutralization is impacted by the PBMC donor used for both virus growth and target cells, and the effects are neutralization reagent-specific
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