Our immune system - Miracle weapon against cancer?| DW Documentary

Key Concepts

Immune system (innate and adaptive), pathogens, cancer, microbiome, T cells, B cells, antibodies, vaccination, autoimmune diseases, inflammation, stress, diet, exercise, immune aging, immunotherapy, cancer vaccines, environmental factors, genetics.

Immune System Overview

The immune system is a complex, distributed organ that protects us from infections, harmful substances, and malignant cell changes, especially cancer. It lacks a fixed location, with immune cells originating in the bone marrow, thymus gland, and lymph nodes, and 70% residing in the intestines. The immune system has two main pillars:

• Innate Immune System: Present from birth, reacts quickly (minutes/hours) to pathogens without prior training. Uses macrophages, neutrophils, and natural killer cells.
• Adaptive (Acquired) Immune System: Develops over time, remembers past threats, and is activated by vaccination. Relies on T cells and B cells.

Birth and Early Childhood Development

• Natural Birth vs. Cesarean: Natural birth is generally considered more beneficial for a child's immune system as it allows for colonization with vaginal and intestinal flora, while C-section babies are primarily colonized with microbes from the mother's mouth and skin. Babies born by C-section are generally a little more susceptible to infections and allergies.
• Breastfeeding: Breastfed children are better equipped to fight off germs than formula-fed children.
• Exposure to Environment: Young children need exposure to their environment to encounter microorganisms and train their immune systems. Overly clean environments may increase the risk of allergies later in life.
• COVID-19 Pandemic Impact: Shielding measures during the pandemic (masks, sanitizer, distancing) led to a delayed exposure to common respiratory illnesses (RSV, flu, rhinoviruses) in children, resulting in a surge of cases when restrictions were lifted.

Adaptive Immune System Details

• T Cells: Produced in the bone marrow and trained in the thymus. Crucial for fighting diseases; a lack of T cells leads to a massive increase in the risk of serious infections. T cell screening is now part of newborn blood tests in some countries (including Germany) to detect immune deficiencies.
• B Cells: Transform into plasma cells and release antibodies to target enemy antigens. Antibodies attach to the outside of viruses, marking them for destruction.
• Antibodies: Produced naturally after exposure to antigens or through vaccination.
• Bruton's Disease: A genetic defect where individuals cannot produce B cells and antibodies, leading to serious infections after the mother's antibodies decrease (around 6-9 months). Eliel, an 8-year-old with Bruton's disease, receives regular antibody infusions to live a normal life.

Factors Influencing the Immune System

Lluis Quintana-Murci's study at the Pasteur Institute identified five key factors:

1. Genetics: Inherited predispositions influence immune responses.
2. Age: Immune system functionality changes with age.
3. Sex: Men are generally more susceptible to infectious diseases, while women are more prone to autoimmune diseases.
4. Smoking: Impacts immune cell function.
5. Cytomegalovirus (CMV): A common herpes virus that alters the immune system. Around half the population in Europe is infected.

The Microbiome's Role

• Definition: The sum total of useful bacteria, viruses, and fungi living in and on our bodies, plus their genes.
• Importance: The microbiome trains the immune system to distinguish between harmful and non-harmful bacteria.
• Development: Microbial contact at birth is crucial for immune system development.
• Diversity: A diverse gut microbiome (300-400 types of bacteria) is essential for a healthy immune system.
• Dysbiosis: A decrease in microbial diversity is associated with inflammatory diseases and abdominal issues.

Diet and Immune Health

• Visceral Fat: Fat around vital organs, thrives on carb-rich diets and high insulin levels, triggers inflammation, and compromises the intestinal barrier.
• Foods to Avoid: Sugar and highly processed foods with additives.
• Foods to Eat: Vegetables (especially wild varieties), fiber, legumes, fruits (especially berries), and omega-3 fatty acids.

Exercise and Immune Aging

• Impact: Exercise influences the aging of the immune system.
• Study: Karsten Krüger's study showed that active individuals over 55 had immune profiles resembling those of people twenty years younger.
• Benefits: Regular exercise and a healthy diet maintain the T-cell repertoire, keeping T cells younger and more effective.

Stress and the Immune System

• Acute Stress: In mice studies, acute stress caused a sharp rise in neutrophils and a drop in B and T lymphocytes, leading to a worse disease course and increased mortality when combined with viral infections (COVID or flu).
• Chronic Stress: Weakens the immune system, especially the adaptive immune system, impairing the ability to fight viral infections and develop a strong immune response to vaccination.
• Wolfram Poller's Research: Using virtual reality, Poller demonstrated that both stress and relaxation influence our immune systems and vaccine effectiveness.

Autoimmune Diseases

• Definition: The immune system mistakenly attacks the body's own cells.
• Causes: Genetic predisposition and environmental factors (infections, pollutants, microbiome, chronic infections).
• Prevalence: Autoimmune diseases are on the rise, affecting around 10% of the population.
• Sex Differences: Women are statistically more affected than men due to stronger immune systems and potential links to sex hormones and X chromosomes.

Immunotherapy and Cancer

• Goal: To use the immune system to recognize and kill cancer cells while preserving healthy tissue.
• Mechanism: Strengthening the immune system's defense mechanisms to control or eradicate tumors.
• T Cells: Play a crucial role in recognizing and destroying tumor cells.
• Personalized Cancer Vaccines: Elements of tumor cells are analyzed and modified to create a vaccine that prompts the immune system to attack malignant cells.
• Multi-Stage Process: Involves a cancer vaccine, isolation and multiplication of immune cells, and infusion back into the patient.
• Dirk Jäger's Research: Using experimental therapy on patients at Germany's National Center for Tumor Diseases.

Conclusion

The immune system is a powerful but vulnerable defense mechanism. Its effectiveness is influenced by genetics, age, sex, lifestyle factors (diet, exercise, stress), and environmental exposures. Maintaining a balanced immune system is crucial for protecting against disease without causing harm. Research into immunotherapy offers promising avenues for treating cancer and autoimmune diseases, but much remains to be learned about specifically modulating immune responses.