“Early-life immune activation has been well-established to regulate the programming of brain development and influence behavior in later life…”

-Dr Zhibin Yao et al, 2016, Sun Yat-Sen University (Consistently ranked among the top 10 universities in mainland China)

An important new study by Li et al. reports that bacillus calmette-guerin (BCG) vaccine (for tuberculosis) and hepatitis B vaccine affect brain development in infant rats. The study relates the observed brain changes to the type of immune activation (Th1 or Th2, explained below) stimulated by the vaccines. The BCG and hep B vaccines produced opposite effects (BCG being beneficial, and hep B being detrimental). The combination of both vaccines resulted in cancellation of the effects.

This is the first study of immune activation by vaccination on brain development. Other studies of immune activation use non-vaccine immune activators like “poly-IC” or lipopolysaccharide. These immune stimulants can create very intense inflammation. A common criticism from vaccine advocates is that the immune activation experiments are not relevant to vaccines because vaccines cause a milder immune activation than injections of poly-IC or lipopolysaccharide. This argument is contradicted by the Li et al study. Li et al proves that vaccines can affect brain development via immune activation.

This new study is very important for the vaccine safety controversy because it connects vaccines with the studies showing that immune activation impacts brain development and causes brain disorders.

Full Paper (Li et al.): Neonatal vaccination with bacillus Calmette–Guérin and hepatitis B vaccines modulates hippocampal synaptic plasticity in rats

BCG vaccine is a live-bacteria vaccine for tuberculosis. It is the only live-bacteria vaccine and it is not part of the US CDC vaccine schedule. It contains no adjuvant (i.e., no aluminum) and contains a single pathogen (MMR contains 3). Consequently, BCG is more similar to a natural infection than other vaccines which contain adjuvants or multiple pathogens.

Hep B vaccine contains neurotoxic aluminum adjuvant.

Th1 and Th2 describe two opposite “modes” of the immune system. Th1 and Th2 can be described as extremes on a scale (though this is a simplification). They refer to different types of T-cells (cells from the thymus, an immune system organ) produced in response to infection. Th1 and Th2 are used to fight different types of infections. For example, Th1 is for things that infect cells (e.g. viruses); Th2 is for worms and parasites. Th2 activation causes allergy and is associated with autism.

Th1 and Th2 produce different patterns of cytokines, and consequently have different effects on the body and brain. The cytokine interferon-gamma (IFN-g) is associated with Th1, and interleukin-4 (IL-4) is associated with Th2 (though Th1 and Th2 each produce a distinctive mix of cytokines). The ratio IFN-g/IL-4 describes the balance between Th1 and Th2:

Th1/Th2 = IFN-g/IL-4

BCG vaccine causes Th1 activation (i.e. IFN-g expression), and hep B vaccine causes Th2 activation (i.e. IL-4 expression). In this study, the BCG and Hep B vaccines had opposite effects on brain development. BCG vaccine was beneficial, and HepB vaccine was harmful. Li et al attribute the benefit and harm to the Th1/Th2 balance. The present study also found that combining both vaccines produced no effect, apparently because the Th1/Th2 balance is not affected when both vaccines are given.

All aluminum-containing vaccines (including Hep B vaccine) induce Th2 activation.

Also, aluminum induces IL-6 expression. Elevated IL-6 causes autism.

Li et al. Study Design

The study used only male rats. Four sets of measurements were performed on control and vaccinated rats at 2, 4, and 8 weeks of age. BCG-vaccinated rats were vaccinated once with BCG. Hep B-vaccinated rats were vaccinated with 3 doses (at 0, 7, and 21 days of age). The study was designed to mimic how these vaccines are used in humans. Li et al states: “The BCG and HBV vaccination procedures imitated those used for human infant vaccinations“.

One group of rats received both BCG and Hep B vaccines; this group is indicated by “BH” in the images below.

Rats were sacrificed at ages 2, 4, and 8 weeks, and the brains were analyzed as described below.

No behavioral tests were performed.

RESULTS

Long term Potentiation in the Hippocampus

An important measurement in this study was “long term potentiation” (LTP) in the hippocampus. The hippocampus is a brain region for learning and memory. Other research shows that the hippocampus is sensitive to cytokines and immune activation. LTP refers to long term changes in synapse connections based on brain activity. LTP is believed to be the fundamental basis for learning and memory. High LTP indicates better memory, and low LTP indicates poor memory. LTP is explained here: https://en.wikipedia.org/wiki/Long-term_potentiation

Finding: BCG vaccination increased LTP (at 2 and 4 weeks), and hep B vaccination reduced LTP at 8 weeks of age. This suggests that the BCG vaccine may improve learning and memory and hep B vaccine may impair learning and memory. This is consistent with immune activation experiments, which demonstrate that IL-6 (associated with Th2) causes impaired learning and memory.

Above: Hepatitis B vaccine caused a reduction of long term potentiation (LTP), indicating adverse effects on learning and memory. BCG vaccine had the opposite effect. When both vaccines are given, the effects cancel. Li et al. attribute the effects to Th1/Th2 balance. From Li et al.

Morphology of Dendritic Spines

“Morphology” refers to the size, length and density of dendritic spines. Dendritic spines are small protrusions on the dendrites of neurons. The morphology of dendrites can indicate neurological disease. For example, dendrite spine density is abnormally low (in some brain regions) in schizophrenia and bipolar disorder. One study reports increased dendrite density in the cortex in autism (a different area of the brain than the hippocampus) Citation: http://www.ncbi.nlm.nih.gov/pubmed/19896929.

Dendrites are affected by immune activation. For example the Patterson research group reported changes in dendrite morphology in monkeys exposed to maternal immune activation. Citation: Preliminary-evidence-of-neuropathology-in-nonhuman-primates-prenatally-exposed-to-maternal-immune-activation )

Finding: BCG and Hep B vaccines had opposite effects on dendritic spine density and spine area. The combination of both vaccines had no effect, indicating that the vaccines cancel each other (“BH”= combination of both vaccines).



Above: Hep B and BCG vaccines had opposite effects on dendritic spine density and spine area. When both vaccines are given, the effects cancel. Li et al. attribute this to changes in Th1/Th2 balance caused by the vaccines. The functional effects of these changes are unknown, but it is known that dendritic spines show abnormalities in many different brain diseases. From Li et al.

Synapse Proteins

Specialized proteins are necessary for proper synapse function (e.g. synaptophysin, PSD-95, and others). Abnormal levels of synapse proteins can indicate neurological diseases. For example, schizophrenia is associated with reduced synaptophysin and reduced PSD95. Synapse protein measurements can be indicative of synapse density.

Finding: Hep B vaccine caused reduced levels of 4 of the 5 synapse proteins measured at age 8 weeks. BCG vaccine had the opposite effect, for 3 of the 5 proteins. The combination of both vaccines (indicated by “BH”) had no effect on synapse proteins.

Above: Hep B and BCG vaccines had opposite effects on the concentration of some brain proteins. When both vaccines are given (the “BH” group), the effects cancel. Li et al. attribute this to changes in Th1/Th2 balance caused by the vaccines. Synaptophysin and PSD95 are reduced in schizophrenia and in immune activation experiments, and by the Hep B vaccine. Increased synapse proteins (from BCG) suggests an increase in synapses; decreased synapse proteins (from Hep B) suggests a decrease in synapses. From Li et al.

A 2015 study by Giovanoli et al. showed that prenatal immune activation (using poly-IC) caused reductions in synaptophysin and PSD95. Giovanoli also observed impaired pre-pulse inhibition, an indicator of schizophrenia and autism. So, the hepatitis B vaccine given postnatally has the same effect (on synaptophysin and PSD95) as prenatal immune activation with poly-IC. This is further evidence that the immune activation studies are relevant to vaccines.

Paper (Giovanoli): Prenatal immune activation causes hippocampal synaptic deficits in the absence of overt microglia anomalies



Cytokine Expression

Cytokines were measured in the hippocampus and blood serum.

Findings: The hep B vaccine increased IL-6 in the hippocampus (the only brain region analyzed for cytokines), after a delay of at least 4 weeks. Elevated IL-6 causes autism. Hep B vaccine also caused Th2 bias at 4 and 8 weeks. BCG caused Th1 bias.



Above: The hep B vaccine increased IL-6 expression in the hippocampus at 8 weeks, but not at 2 or 4 weeks. This delay means the impact on brain development may take months to appear. Elevated IL-6 causes autism. From Li et al.

Above: Th1/Th2 balance as measured in the blood. Hep B vaccine caused Th2 polarization at 4 and 8 weeks, which suggests that the Hep B vaccine has long-term effects on Th1/Th2 balance. Aluminum adjuvant causes Th2 activation and long term Th2 bias.

Relevance of Th1/Th2 Balance to Autism

The immune systems of autistics are biased toward Th2. Autistics have abnormally low IFN-g (associated with Th1), and abnormally high IL-4 (associated with Th2). So, autistics have the same immune system imbalance produced by the hepatitis B vaccine in the Li study. Also, it is known that aluminum adjuvant causes Th2 bias. The Hep B vaccine contains aluminum adjuvant and the BCG vaccine does not contain aluminum adjuvant (BCG vaccine contains no adjuvant).

See for example these results from a study measuring Th1/Th2 bias in human autistics. Measurements of IL-4, IFN-g, and IL-2 confirm the Th2 bias in autism. IL-2 is associated with Th1, so low IL-2 confirms Th2 bias in autism. Paper (Gupta et al): Th1- and Th2-like cytokines in CD4 and CD8 T cells in autism

Above: In human autism, IFN-g is abnormally low, and IL-4 is abnormally high. Both indicate a shift toward Th2, just like the animals that received the hepatitis B vaccine. Note that IL-2 is also associated with Th1, so the abnormally low IL-2 confirms the shift away from Th1. From Gupta et al.

A January 2017 paper confirms the Th2 bias in autism, from measurements of chemokines (another class of immune system-signaling substances). It discovered “…elevated…levels of the Th2-related chemokine CCL5 and reduced levels of the T helper type 1 (Th1)-related chemokine CXCL9 in children with ASD compared to typically developing controls“. Paper: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5253384/

Vaccine Effects Take Months to Appear

An important finding in the Li et al study is that some of the effects of hep B vaccine did not appear until age 8 weeks. This finding undermines claims of vaccine safety, which are almost always based on short-term outcomes of a few days or weeks. 8 weeks is a long time in rat development. 8 week old rats are almost fully mature adults. This suggests that adverse effects of vaccines may take years or decades to appear in humans, and can be life-long. This is consistent with what is known about immune activation and schizophrenia. Immune activation in a fetus can cause schizophrenia 20-30 years later.

The accumulating scientific evidence and the Li et al study in particular strongly suggest that early-life vaccination may cause mental illness. The mental illnesses can emerge years or decades after vaccination of an infant.

Vaccines are likely contributing the the rise of mental illnesses in the USA over the last 25 years. The rise in mental illnesses in the USA is coincident with the dramatic increase in vaccination that started in the late 1980s.

Conclusion

The paper concludes:

“We propose a hypothesis that a systemic Th1/Th2 bias modulates central cytokines and neurotrophins and thereby affects the neurogenic niche, which is tightly correlated with synaptic plasticity. Previous reports support this hypothesis. It was reported that cognitive deficit was related to decreased Th1/Th2 balance in periphery and could be recovered when the balance was restored (Jakobsson et al., 2014; Palumbo et al., 2012).” “..our data suggested that combinations of different vaccines can mutually interact (enhance or counteract). The mechanism of synaptic plasticity modulation through neonatal BCG/HBV vaccination may be via systemic Th1/Th2 bias accompanied by a specific profile of cytokines and neurotrophins in the brain. Our work highlights a critical role of neonatal vaccination in synaptic plasticity outside of infectious disease prevention, which suggests the necessity of further studies on the association of vaccination with brain development under normal physiological conditions.”

UPDATE

An April 2016 paper from the same research group (led by Dr Zhibin Yao) demonstrates that BCG vaccine has long-term effects on immune system “programming”. Specifically, the new paper shows that BCG vaccination during early development affected the adult response to immune stimulation. In other words, BCG vaccine had long-lasting (perhaps life-long) effects on how the immune system responds to immune stimulation.

In this study, mice were given BCG vaccine (or saline placebo) at birth. Then, the mice were given lipopolysaccharide (LPS, an immune stimulator) as adults. The study had 4 groups:

1) Saline control at birth

2) BCG (@birth)

3) LPS (@12 weeks)

4) BCG+LPS (@birth and 12 weeks)

Full Paper(Yang et al): Neonatal Bacillus Calmette‐Guérin vaccination alleviates lipopolysaccharide‐induced neurobehavioral impairments and neuroinflammation in adult mice

The results show that early-life BCG vaccination reduced the inflammatory and behavioral response to immune stimulation in adults. Interestingly, BCG vaccine had no effect on behavior or immune function in the absence of immune stimulation.

This experiment elegantly illustrates that early life exposures have long term effects on immune system function. The BCG vaccine caused long-term programming of the immune system.

These results suggest the Hep B vaccine may have the opposite effect. Early life Hep B vaccination may program the immune system to have increased immune response in adults.



Above: BCG vaccination at birth affects the behavioral response to immune activation in adult (12 week old) mice. Mice that received BCG as infants were less affected by LPS as adults 12 weeks later. From Yang et al. 2016.

Papers in this post: