Session Notes on Immunoglobulins and Macrophages

Immunoglobulins (Ig) are glycoprotein molecules produced by plasma cells (a type of white blood cell) and are critical for immune function. There are five main types of immunoglobulins in humans: IgA, IgE, IgG, and others.

Location and Function:
- Predominantly found in tears and mucus.
- Plays a crucial role in mucosal immunity, protecting mucous membranes lining the digestive and respiratory tracts.
Importance:
- Acts as the first line of defense against pathogens that enter the body through mucosal surfaces.
- Provides a protective barrier, preventing the colonization of pathogens.

Location and Function:
- Primarily associated with allergic reactions.
- Binds to allergens and triggers histamine release from mast cells and basophils.
Importance:
- Involved in the body's response to parasites (such as helminths) but is largely recognized for its role in allergies.
- Low concentrations in the bloodstream compared to other immunoglobulins.

Location and Function:
- Found mainly in blood and extracellular fluid.
- Makes up approximately 75-80% of serum immunoglobulins.
Importance:
- Provides the majority of antibody-based immunity against invading pathogens.
- Capable of crossing the placenta, providing passive immunity to the fetus.

Definition:
- Large white blood cells that are part of the immune system.
Role in Immune Response:
- Known as important fighters in the immune response. They are crucial for both the innate and adaptive immune systems.
- Engulf and digest cellular debris, foreign substances, microbes, and cancer cells through a process called phagocytosis.
Importance:
- Act as antigen-presenting cells by processing and presenting antigens to T cells, which then activate other immune responses.
- Release cytokines that recruit and activate other immune cells, enhancing the immune response.