Thread by @AurelianoStingi

LAMBDA variant is antibody resistant? It will overcome the vaccine?
Let's discover it together!
First of all let's dive into the neutralization assay
1/n

As you can appreciate from the scheme the neutralization assay evaluates the antibodies ability to neutralize viral replication. Is pretty 'simple' you plate human cells and you infect them with the virus. 2/n

As you expected the virus will infect 100% of the cells, instead if you add antibodies those will neutralize the virus. In this second situation, you can see that the antibodies reduced viral replication by 80% meaning that only 20% of the cells are infected. 3/n

Let's see what happen with a Sars-CoV2 variant, as we know a variant is characterized by several mutations, some of which MAY impair antibody recognition, decreasing the neutralization. 3rd situation, Sars-CoV2 variant is only partially recognized. %0% reduction 4/n

Ok, that's how the neutralization assay works.
+Is neutralization assay able to predict vaccine response?
-Partially
+why?
-Because the immune system is not only antibodies!
5/n

Imagine the Immune system as an ARMY composed of several different types of soldiers:
T cells
B cells
Dendritic cells
Natural Killer
Mast cells
etc etc
That's why neutralization assay is not sufficient to predict the response to a new variant. 6/n

Coming to Lambda, different papers indicated it likeable to overcome vaccine protection. All the data are produced in vitro in lab (with the assay aforementioned). 7/n
biorxiv.org/content/10.110…
medscape.com/viewarticle/95…

TAKE HOME MESSAGES:
1) neutralization assays are an approximation and are limited
2) immune response doesn't rely ONLY on neutralizing antibodies
3)A neutralization reduction doesn't imply immune escape or no protection
Let's monitor Lambda evolution but DON'T PANIC