Affinity Maturation
How does the immune system develop antibodies specific to newly emerged pathogens?
Antibody maturation takes place in Germinal Centers formed in lymph nodes:
The processes of (hyper)mutation/competition/selection is akin to rapid evolution through natural selection,
with success at binding/internalizing pathogen judged by Helper T cells.
Use concepts/results from population evolution to describe/quantify affinity maturation:
Desirable trait ω (binding affinity): Ability of B cell receptor (proto antibody) to stick to viral spike
Fitness f(ω) (reproductive capacity): Likelihood of procreating progeny B cells with trait ω
Roland Fisher's Fundamental Theorem of Natural Selection
"The rate of increase in fitness is related to variance (spread) of fitness in the population"
With variability maintained through (hyper-) mutations, the mean value of a trait, such as the affinity ω, through
George Price's Equation:
"The rate of change in trait is related to its variance (correlation) to fitness in the population"
In words: Traits evolve to values conferring higher fitness, more rapidly if there is more variation in the population.
To use the 
equations in Affinity Maturation, we need to describe the dependence of fitness on affinity.
Computational Model:
