Human Immunity and Blood

Monoclonal antibody OKT3 has antigen of type T3, which represents reactivity with epidermal Langerhan’s cells.

Selectins bind to sugar moieties and are considered to be a type of lectin.

The gene for factor VIII is located on the X chromosome. Factor VIII is produced in liver sinusoidal cells and endothelial cells outside of the liver throughout the body.

IgW and IgY are not found in mammals. IgWs are found in birds and reptiles. IgYs found in sharks and skates.

Lymphocytes are the second most common white blood cells (20 - 45% of all leukocytes).

Natural Killer Cells (or NK cells) are a type of cytotoxic lymphocyte critical to the innate immune system. NK cells provide rapid responses to virally infected cells and respond to tumor formation. Helper T cells help the activity of other immune cells by releasing T cell cytokines. They are essential in B cell antibody class switching, in the activation and growth of cytotoxic T cells, and in maximizing bactericidal activity of phagocytes such as macrophages. The principal functions of B cells are to make antibodies against antigens.

Lymphocytes and monocytes are types of agranular leukocytes.

Heparin is a naturally occurring anticoagulant produced by mast cells and basophils. It prevents blood clot formation by enhancing the activity of antithrombin III, which inhibits thrombin and other clotting factors. Fibrinogen and thrombin are actually pro-coagulant substances involved in clot formation, while globin is a protein component of hemoglobin.

Kupffer cells are resident macrophages lining liver sinusoids, phagocytosing pathogens, damaged cells, and debris from blood passing through the liver. They're not found in heart, spleen (which has different macrophage types), or pancreas.

Basophils are the rarest white blood cells, comprising only 0.5-1% of total WBC count. Neutrophils are most abundant (60-70%), eosinophils make up 1-3%, and monocytes account for 2-8%. This rarity makes basophils easily identifiable in blood smears.

These terminal components form a complex which inserts into the membrane to form a transmembrane ion channel which leads to lysis of the cell.

C5a is a powerful chemotactic agent and also an anaphylatoxin.

Activation of mast cells releases chemotactic factors for neutrophils and also vasoactive mediators such as histamine.

The alpha chain is specific for each VLA molecule (for example, VLA-1 is an alpha1beta1 molecule whilst VLA-6 is an alpha6beta1 molecule).

The high-walled endothelium of the post-capillary venules (HEV) in lymph nodes express vascular addressins, which are recognised by homing receptors on lymphocytes passing through the afferent lymphatics and which mediate entry of the lymphocytes into the lymph nodes.