Measles Vaccine and Gain-of-Function: The Inconvenient Truth About CD150/CD46 Tropism Shift

Children's Health Defense deleted my interview segment after I cited peer-reviewed research confirming the measles vaccine virus was created with GOF techniques.

Immediately after my Monday appearance on Children’s Health Defense (CHD), many criticized my explanation that the measles vaccine virus was developed through experiments that could be classified as gain-of-function (GOF) research.

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These individuals claim the process of making the measles vaccine virus does not qualify as GOF.

After the organization received similar claims about my explanation, CHD decided to delete a clip of my segment from their Twitter/X account, despite it garnering tens of thousands of views in a matter of hours.

Here’s the segment, which I screen recorded before CHD deleted it:

They also pulled the clip despite it clearly showing me stating that the explanation that the measles vaccine virus was created through GOF comes from a peer-reviewed journal publication written by biodefense experts (see below).

To be fair, CHD did leave up the full show, which featured other guest appearances in addition to my segment.

I have been a supporter of Children’s Health Defense since its founding in 2016 and will continue to support its work.

I encourage everyone to follow CHD and to support their incredible mission financially.

However, the claim that the measles vaccine (MMR) wasn’t developed using techniques that could be considered GOF is factually incorrect.

Parents deserve to know that when they give their children an MMR vaccine, their children are being injected with a live virus that has been engineered using techniques that could be considered gain-of-function, a practice that led to the deadly COVID-19 pandemic.

And that such experiments are subject to bioweapons creation rules enshrined in the 1989 Antiterrorism Act.

Manipulating pathogens in the lab is referred to as ‘Dual-Use Research of Concern’ (DURC) because any pathogen created through such means could inherently be used as either a treatment or a weapon (hence “dual” -use).

Measles virus manipulation requires (here) a Biosafety Level 2 (BSL-2) laboratory rating because the paramyxovirus is classified as a Risk Group 2 agent.

A close examination of the scientific literature, including peer-reviewed research and U.S. biodefense policy, proves the measles vaccine virus gained the function of enhanced human cell infectivity compared to the wild-type virus, characteristics that align with GOF modifications.

These are inconvenient truths for Big Pharma, its allies, and those who don’t want you to know how vaccines are made.

Understanding Gain-of-Function: Definition and Policy Concerns

A 2022 Congressional Research Service report titled Oversight of Gain of Function Research with Pathogens: Issues for Congress defines gain-of-function as:

“any genetic mutation in an organism that confers a new or enhanced ability. Such changes often occur naturally. Additionally, scientists can induce such changes to organisms through experimentation. Gain-of-function (GOF) research is a broad area of scientific inquiry involving organisms that gain a new property or have an existing property altered.”

The report also acknowledges that while some scientists argue this research is necessary to improve medical countermeasures and surveillance for emerging pathogens, others express concerns over the risks posed by accidental release or deliberate misuse. Given the potential for widespread impact, there is an ongoing debate about whether the risks of GOF research outweigh its purported benefits.

The American Society for Microbiology similarly defines GOF as techniques that are used in research to “alter the function of an organism in such a way that it is able to do more than it used to do.”

CD150 to CD46: A Clear Gain-of-Function Event

One of the most compelling pieces of evidence demonstrating that measles vaccine development involved GOF is the receptor shift from CD150 (SLAM) to CD46. The wild-type measles virus (Montefiore 89 strain) primarily uses CD150 as its receptor to infect immune cells. However, tissue culture adaptation led to the vaccine strain (Edmonston strain) acquiring the ability to bind CD46, a receptor that is much more broadly expressed on most human nucleated cells.

The measles vaccine strain—injected into the vaccinated—has the potential to enter a wider range of cell types in laboratory settings compared to the wild-type virus, due to its acquired ability to use an additional cellular receptor.

“CD46 (also known as membrane cofactor protein or MCP) is a regulator of complement activation that is expressed in most or all human nucleated cell types,” a May 2004 Journal of Virology publication confirms, emphasizing the breadth of CD46’s distribution throughout the human body.

This is not a loss of function—it’s a textbook example of functional expansion, which is by definition a gain-of-function event. The virus gained the ability to infect a wider range of cells. This receptor switch represents an acquired trait due to repeated passaging in vitro, confirming that tissue culture adaptation enhanced the virus’s capability rather than reducing it.

The scientific literature supports this categorization. In a May 2016 publication in The Journal of Infectious Diseases, U.S. military biodefense experts explicitly state:

“The live-attenuated measles vaccine was created by passaging the virus until mutations arose that altered virus tropism—a technique that could be considered, by current definitions, GOF research.”

Viral tropism refers to the ability of a virus to productively infect specific cells, tissues, or host species.

A footnote in that paper references an earlier publication (Measles: Old Vaccines, New Vaccines, Griffin & Pan, 2009), which further confirms how the measles vaccine virus underwent significant receptor binding changes due to serial passaging.

That earlier publication reads:

“To date, two human receptors for MV have been identified: CD46 (Dorig et al. 1993; Naniche et al. 1993) and signaling lymphocyte activation molecule (SLAM; Erlenhoefer et al. 2001; Hsu et al. 2001; Tatsuo et al. 2000). While this is still an evolving field, and many believe that other receptors will be identified in the future, the general consensus is that CD46 is principally a receptor for vaccine strains, such as Edmonston, whereas SLAM, though restricted to hematogenous cells, permits entry of wild-type MV.”

Elsewhere, the paper explicitly states that “wild-type isolates typically use SLAM (Erlenhoefer et al. 2001; Ono et al. 2001a, 2001b; Tatsuo et al. 2000), whereas attenuated vaccine strains, such as Edmonston and the strains derived from it, preferentially use CD46.”

The vaccine virus’s acquisition of the ability to use CD46 as an additional receptor, while retaining its ability to use CD150, dramatically increased its infectivity. This expansion from primarily targeting activated immune cells to potentially infecting almost all nucleated human cells made the virus significantly more infectious, possibly by orders of magnitude.

Mechanisms of Change: Mutations Allowing CD46 Adaptation

A 2016 review in Viruses provides additional molecular insights into how the measles virus adapted to CD46 receptor usage. The study confirms that specific mutations in the hemagglutinin (H) protein—N481Y and E451V—allowed vaccine strains to bind to CD46, while wild-type measles virus strains do not. These mutations arose only during laboratory adaptation, confirming the vaccine strain’s altered tropism as a direct result of GOF research.

Additionally, a 2002 study in Virology (doi:10.1006/viro.2002.1471) demonstrated that:

• CD46 binding by measles virus was an in vitro adaptation, not a natural trait. Wild-type measles virus (MV) primarily uses CD150 (SLAM), while vaccine strains adapted to CD46 through tissue culture passaging.

• Single amino acid substitutions (N481Y, E451V) enabled the virus to bind CD46, reinforcing that this receptor shift was an acquired function.

• Most wild-type MV strains in the body use SLAM as their receptor, further proving that CD46 tropism is a lab-induced gain-of-function adaptation.

• Some MV strains can enter cells without using SLAM or CD46, suggesting the presence of yet another, unidentified receptor, expanding the virus’s functional capabilities beyond natural limits.

Conclusion: The Facts Remain the Same

The measles vaccine virus underwent a clear gain-of-function during its development, particularly in its receptor usage. The shift from CD150 to CD46 is the strongest evidence of this, as it demonstrates a functional gain that allowed the virus to infect a broader range of human cells.

Whether attenuation occurred is irrelevant to the fact that the virus gained a new capability during lab manipulation. This is not opinion—it’s documented in peer-reviewed literature and confirmed by U.S. biodefense experts.

As the scientific and legal definitions stand today, the measles vaccine virus was created using GOF techniques. Any claim to the contrary ignores the evidence.

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