Immune System and Mucous Membranes

Mucus and Membranes

• Mucus is a slimy secretion covering membranes.
• Mucous membranes line inner organs and body cavities (like nose, mouth, lungs).
• Mucosal-associated lymphoid tissues (MALT) are lymphoid tissues located along mucous membranes in the digestive, respiratory, and urogenital tracts.

Immune Cells and Function

• Interstitial macrophages are smaller and less phagocytic than alveolar macrophages, found in lung stroma.
• Alveolar macrophages phagocytose particles in alveoli.
• Innate immune cells include myeloid cells (like dendritic cells and macrophages).
• Adaptive immune cells include lymphoid cells (like B and T cells).
• Immunity is influenced by genotype, diet, exercise, microbiota, stress, and antibiotics.
• Dysbiosis is chronic inflammation where the immune system struggles to tolerate good microbes and eliminate bad ones.
• Chronic inflammation is generally harmful.
• Primary lymphoid organs are where immune cells are generated.
• Secondary lymphoid organs are where immune cells function.
• Immune cells travel through the lymphatic system and blood vessels.
• Humoral response involves blood and plasma.
• Cell-mediated response involves T cells.
• Innate cells have microbial sensors (pattern recognition receptors like TLR) to recognize pathogens.
• Dendritic cells recognize, destroy, and present pathogen parts to T cells.
• The immune system recognizes self and foreign substances/microbes. It also cleans up old cells.

Immunity and Immunology

• Immunity is the body's ability to resist disease.
• Immunology is the science of immune responses.
• The immune system distinguishes self from altered self, self from foreign invaders, and different foreign pathogens.

Immune Response and Vaccination

• Effector responses eliminate pathogens. Vaccinations create immunological memory for faster responses to re-exposure.
• Protein antigen-based vaccines use a portion of a virus for immune recognition, triggering B and T cell responses
• Inactivated virus vaccines introduce the entire virus structure, allowing immune cells to recognize multiple antigenic parts for a broader response.
• mRNA vaccines enable the body to make proteins (antigens) through mRNA translation.
• Flu vaccines target HA (viral entry) and NA (viral exit).

History of Vaccination

• Thucydides observed plague survivors' resistance.
• Variolation involved exposing people to smallpox pustules.
• Edward Jenner developed the first smallpox vaccine by using cowpox.
• Smallpox was a highly contagious disease that left severe scarring and has now been eradicated.
• Louis Pasteur developed vaccines for rabies and anthrax.
• Pasteur's rabies vaccine conferred both active and passive immunity.

Immune System and Disease

• Opportunistic infections are common in individuals with weakened immune systems, such as those with AIDS.
• Active immunity is generated by the body's response to a pathogen.
• Passive immunity involves receiving antibodies from another source (e.g., breast milk).
• Historically, antisera were used to treat patients before antibiotics.

Nobel Laureates and Discoveries

• Scientists were awarded Nobel Prizes for major discoveries regarding the immune system, including MHC, antibody production, and innate immunity.

Specific Diseases: Mumps

• Mumps is a viral infection causing salivary gland swelling, most common in unvaccinated children (2-12 years old).
• Incubation period for mumps is 12-24 days. MMR vaccination is recommended for children during different age stages.