AUTHOR=Meyer-Hermann Michael , Binder Sebastian C. , Mesin Luka , Victora Gabriel D. 

TITLE=Computer Simulation of Multi-Color Brainbow Staining and Clonal Evolution of B Cells in Germinal Centers

JOURNAL=Frontiers in Immunology

VOLUME=Volume 9 - 2018

YEAR=2018

URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2018.02020

DOI=10.3389/fimmu.2018.02020

ISSN=1664-3224

ABSTRACT=Clonal evolution of B cells in germinal centres (GCs) is central to 
affinity maturation of antibodies in response to pathogens. 
Permanent or tamoxifen-induced multi-colour recombination of B cells 
based on the brainbow allele allows 
monitoring the degree of colour dominance in the course of the GC reaction.
Here, we use computer simulations of GC reactions in order to replicate
the evolution of colour dominance in silico and to define rules for the
interpretation of these data in terms of clonal dominance.
We find that a large diversity of clonal dominance is generated 
in simulated GCs in agreement with experimental results. In the extremes,
a GC can be dominated by a single clone or can harbor many co-existing clones.
These properties can be directly derived from the measurement of colour
dominance when all B cells are stained before the GC onset.
Upon tamoxifen-induced staining, the correlation between clonal structure
and colour dominance depends on the timing and duration of the staining procedure
as well as on the total number of stained B cells.
%The time point of tamoxifen-induced staining is critical: Too early
%reduces the number of lineages, too late reduces the correlation because
%of staining ambiguities.
B cells can be stained with 4 colours if a single brainbow allele is used, using
both alleles leads to 10 different colours.
The advantage of staining with 10 instead of 4
colours becomes relevant only when the 10 colours are attributed with rather similar
probability. Otherwise, 4 colours exhibit a comparable predictive power.
These results can serve as a guideline for future experiments based
on multi-colour staining of evolving systems.