Pseudotypes-based Neutralization Assay (PP-MN)
The pseudovirus particle–based microneutralization (PP‑MN) assay evaluates the ability of antibodies elicited by infection or vaccination to neutralize a virus of interest using a replication‑incompetent surrogate virus, providing a safe alternative to assays employing live pathogenic viruses.
In the PP-MN assay, pseudoviruses are generated by incorporating one or more envelope or surface proteins of the target pathogen into a heterologous viral backbone (e.g., lentiviral or VSV‑based systems). These particles retain the ability to enter target cells but are incapable of replication. Serially diluted serum samples are incubated with the pseudovirus prior to infection of permissive cells. Neutralizing antibodies inhibit pseudovirus entry, resulting in reduced reporter gene expression (e.g., luciferase or GFP). Neutralization is quantified by comparing reporter signals in the presence and absence of serum and calculating the half-Maximal Inhibitory Concentration (IC50) for each sample. The PP‑MN assay enables safe, high‑throughput evaluation of functional neutralizing antibody responses without the need for high‑level biocontainment. This approach is particularly valuable for high‑risk pathogens requiring BSL‑3 or BSL‑4 containment, including SARS‑CoV‑1 and SARS-COV-2 (Characterisation of SARS-CoV-2 Lentiviral Pseudotypes and Correlation between Pseudotype-Based Neutralisation Assays and Live Virus-Based Micro Neutralisation Assays. , Standardised quantitative assays for anti-SARS-CoV-2 immune response used in vaccine clinical trials by the CEPI Centralized Laboratory Network: a qualification analysis , Development of bivalent RBD adapted COVID-19 vaccines for broad sarbecovirus immunity), MERS‑CoV, Ebola virus, Marburg virus, Lassa virus (A validated and standardized pseudotyped microneutralization assay as a safe and powerful tool to measure LASSA virus neutralising antibodies for vaccine development and comparison Development and validation of a pseudotyped virus neutralization assay for quantification of anti-Lassa virus neutralizing antibodies), Nipah virus, Hendra virus – for all of which VisMederi has implemented pseudotype neutralization assay platforms.
VisMederi developed its PP-MN assays with both lentiviral and VSV-based vectors.
