Human Immunity and Blood

Phagocytosis, inflammation, and NK cell activity are all types of innate immune responses.

Neutrophils are the most abundant type of white blood cell and are the first responders to inflammation. They are phagocytic cells, meaning they engulf and destroy foreign particles and pathogens.

Formation of scar tissue is a consequence of chronic inflammation, not a mechanism by which inflammation is resolved.

Eosinophils are a type of white blood cell that play a crucial role in defending against parasitic infections. They release toxic substances that damage and kill parasites.

Antibodies are not inflammatory mediators, although they play a crucial role in the adaptive immune response.

Basophils are a type of white blood cell that release histamine and other inflammatory mediators, such as leukotrienes and prostaglandins, which contribute to the development of inflammation.

Tumor antigens are molecules that are expressed on cancer cells and can be recognized by the immune system. These antigens can be derived from mutated proteins, overexpressed proteins, or proteins that are normally expressed in low levels.

Immune checkpoints are molecules that regulate the immune response. These molecules can be expressed on immune cells or cancer cells, and they can either activate or suppress the immune response.

Tumor antigens can be classified into three main types: mutated proteins, overexpressed proteins, and proteins that are normally expressed in low levels. Mutated proteins are proteins that have been altered due to mutations in the DNA of cancer cells. Overexpressed proteins are proteins that are expressed at higher levels in cancer cells compared to normal cells. Proteins that are normally expressed in low levels are proteins that are expressed at low levels in normal cells, but are expressed at higher levels in cancer cells.

Cytotoxic T cells are a type of immune cell that is primarily responsible for recognizing and destroying cancer cells. These cells can recognize tumor antigens presented on the surface of cancer cells and kill them through the release of cytotoxic molecules.

PD-1 (Programmed cell death protein 1) is an example of an immune checkpoint molecule. It is expressed on the surface of T cells and plays a role in regulating the immune response. In cancer, PD-1 can interact with its ligand PD-L1, which is expressed on cancer cells, leading to the suppression of T cell activity and allowing cancer cells to escape immune surveillance.

Tumor-infiltrating lymphocytes (TILs) are immune cells, such as T cells, that infiltrate and accumulate within the tumor microenvironment. The presence of TILs is often associated with a strong anti-tumor immune response and a better prognosis for cancer patients. TILs can recognize and attack cancer cells, contributing to tumor regression and improved patient outcomes.

BCRs are composed of a membrane-bound immunoglobulin molecule, called the antigen-binding fragment (Fab), and a transmembrane protein, called the Fc fragment. The Fab fragment is responsible for binding to antigens, while the Fc fragment is responsible for signaling to the B cell.

A single B cell can express several different types of BCRs, each with a different specificity for antigen. This allows B cells to recognize a wide range of different antigens.

When a BCR binds to an antigen, the B cell is activated. This activation process leads to the production of antibodies and the differentiation of B cells into memory B cells.