Human Immunity and Blood

Lymph is the clear-to-yellowish fluid in intercellular spaces and lymphatic vessels. It's derived from interstitial fluid and contains white blood cells, similar to blood plasma.

Blood platelets (thrombocytes) are cell fragments that are essential for blood clotting. They clump together at the site of injury and release clotting factors. RBCs carry oxygen, WBCs fight infection, and lymph is part of the lymphatic system - none directly cause clotting.

Blood type O negative is the universal donor because it lacks A, B, and Rh antigens on red blood cells. This means it won't trigger an immune response in recipients with any blood type. Type A, B, and AB all have antigens that would react with incompatible recipients.

Blood consists of RBCs, WBCs, platelets, and plasma. 'Plasanta' is not a real blood component - it appears to be a typo, likely intended to be 'placenta' (which is an organ during pregnancy, not in blood) or it's a nonsense word. Either way, it's correctly identified as not being present in 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.

This is the correct answer because anitschkow cells are not found in pemphigus.

Downey cells are seen in infectious mononucleosis.