AUTHOR=Schulz Robert , Werner Benjamin , Behn Ulrich
TITLE=Self-Tolerance in a Minimal Model of the Idiotypic Network
JOURNAL=Frontiers in Immunology
VOLUME=Volume 5 - 2014
YEAR=2014
URL=https://www.frontiersin.org/journals/immunology/articles/10.3389/fimmu.2014.00086
DOI=10.3389/fimmu.2014.00086
ISSN=1664-3224
ABSTRACT=We consider the problem of self tolerance in the frame of a minimalistic model of the
idiotypic network. A node of this network represents a population of B lymphocytes of the
same idiotype which is encoded by a bit string. The links of the network connect nodes
with (nearly) complementary strings. The population of a node survives if the number of
occupied neighbours is not too small and not too large. There is an influx of lymphocytes
with random idiotype from the bone marrow. Previous investigations have shown that this
system evolves toward highly organized architectures, where the nodes can be classified
into groups according to their statistical properties. The building principles of these
architectures can be analytically described and the statistical results of simulations
agree very well with results of a modular mean-field theory. In this paper we present
simulation results for the case that one or several nodes, playing the role of self, are
permanently occupied. These self nodes influence their linked neighbours, the autoreactive
clones, but are themselves not affected by idiotypic interactions. We observe that the
group structure of the architecture is very similar to the case without self antigen, but
organized such that the neighbours of the self are only weakly occupied, thus providing
self tolerance. We also treat this situation in mean-field theory which give results in
good agreement with data from simulation. The model supports the view that autoreactive
clones which naturally occur also in healthy organisms are controlled by anti-idiotypic
interactions, and could be helpful to understand network aspects of autoimmune
disorders.