Saturday, January 24, 2015

Nurture Immunity: Immune system influenced more by environment than by genes

Differences in immune protection presumably explain why some people exposed to infection resist disease or recover while others succumb.  These authors sought to distinguish the influences of genes and environment on immunity. They compared the cellular and molecular components of the immune system among 210 twins: 78 monozygotic (MZ, “identical”) and 27 dizygotic (DZ, fraternal) pairs.  They measured 43 serum proteins and 72 immune cell populations repeatedly and longitudinally (over time) to assess actual variations and account for technical variations.  MZ twins, who have practically identical genomes, and DZ twins, who share half their genes, are especially valuable for assessing the relative contributions of “nature or nurture” (genes or environment) to phenotype.  Their analysis allowed them to detect as little as 20% heritability.

The levels of few proteins and cell populations are under strong genetic control, such as interleukin-6 and CD4+ “central memory” T cells, but most are only weakly heritable or not at all (Fig 1). They found that a common, chronic infection, by cytomegalovirus (CMV), influences the levels of most (58%) cell populations and proteins (Fig 5).  Variation between twins increased as they age, probably reflecting different environmental stimuli and epigenetic changes (Fig 4).  Most intriguing, they correlate the heritability of response to vaccines to the age of immunization, whereby early childhood vaccines are highly heritable while vaccines after early adolescence have no detectable heritability (Table 1, shown below).  

Brodin et al. Cell. 2015 Jan 15;160(1-2):37-47. Variation inthe human immune system is largely driven by non-heritable influences. 


Anonymous said...

CMV is known to interfere with antigen presentation by HLA, so the influence on cells and proteins may be indirect. Another prevalent, clinically-important, chronic infection is EBV, which is usually acquired during the interesting pre- to post-adolescent shift in the influence of heritability on immunity.

Carfilzomib said...

Epigenetic reasons are the most influential factors to the development of immune system. Thus it can be strengthened. But from which aspects that immune system can be improved should be further studied in this research.

SILPeptide said...

As is known, a number of factors can affect the body's immune system: poor diet, certain steroids, chronic stress. Now researchers have discovered that an appetite-controlling hormone can also affect the immune system, while natural versions of certain steroids do not. For my view, scientists should try to discover more applicable methods for improving immune system.