The evidence begins way back in the 1930s with Hans Seyle, who apparently was really guilty of animal cruelty, injecting mice so hard the needle broke in many cases and dropping them on the floor etc., etc.
From Google Images.
Here we read:
Hans Selye (1907–1982): Founder of the stress theory (nih.gov)
"The relationship between stress and disease is now well established, but was not always recognised. "
Indeed not recognized you can be accused of medical misinformation for saying so!
WebMed mentions it in passing.
Your Immune System: Things That Can Weaken It (webmd.com)
This paper:
Psychological Stress and the Human Immune System: A Meta-Analytic Study of 30 Years of Inquiry (nih.gov)
Says: “The most chronic stressors were associated with the most global immunosuppression, as they were associated with reliable decreases in almost all functional immune measures examined. Increasing stressor duration, therefore, resulted in a shift from potentially adaptive changes to potentially detrimental changes, initially in cellular immunity and then in immune function more broadly.”
However they seem to be saying the reverse in their conclusion. "Further research is needed to support two other ideas elicited by this quote: the idea that subjective experience such as worry is more likely to result in stress-related immune change than objective experience and the idea that stress-related immune change results in stress-related disease. "
Here:
What Happens When Your Immune System Gets Stressed Out? – Health Essentials from Cleveland Clinic
Clinical immunologist Leonard Calabrese says that
" stress decreases the body’s lymphocytes — the white blood cells that help fight off infection. The lower your lymphocyte level, the more at risk you are for viruses, including the common cold and cold sores. "
The APA here:
Stress Weakens the Immune System (apa.org)
" In the early 1980s, psychologist Janice Kiecolt-Glaser, PhD, and immunologist Ronald Glaser, PhD, of the Ohio State University College of Medicine, were intrigued by animal studies that linked stress and infection. From 1982 through 1992, these pioneer researchers studied medical students. Among other things, they found that the students’ immunity went down every year under the simple stress of the three-day exam period. Test takers had fewer natural killer cells, which fight tumors and viral infections. They almost stopped producing immunity-boosting gamma interferon and infection-fighting T-cells responded only weakly to test-tube stimulation. "
But then stress can be whatever you want it to be. So if we are going to call a wound or surgery stress then hey stress can BOOST immunity.
Study explains how stress can boost immune system | News Center | Stanford Medicine
There is plenty of evidence after all big companies have been built and profit hugely from the production of genetically modified mice, i.e., transgenic mice.
Here Taconic Biosciences is one.
Human ACE2 Mice for COVID-19 Research - YouTube
And as you can see they are using their mice in all manner of research from studying the disease of covid 19 to making and testing vaccines. And of course for other diseases such as cancer.
"That century of scientific exploration has led to the development of more than 100,000 strains, including many with genetic mutations designed to reveal the role of one or more genes in human disease. "
Human ACE2 Models for COVID-19 Preclinical Research | Taconic Biosciences
More generally: Genetically Engineered Rodent Models | Humanized Mice | Taconic Biosciences
They boast “More Than 4,500 Genetically Engineered Mice & Rat Models”