Human Immunity and Blood

Natural killer (NK) cells are a type of lymphocyte that play a major role in the host-rejection of both tumours and virally infected cells. They provide an immediate, non-specific immune response.

Mast cells, which are a type of connective tissue cell, are the primary source of histamine in the body. Histamine is released during allergic reactions.

Lymph is a clear fluid that lacks red blood cells (erythrocytes), which is the key difference from blood. It contains white blood cells (lymphocytes) but no red blood cells or platelets. Lymph does contain plasma-like fluid (lymphatic fluid), so option A is incorrect. The absence of red blood corpuscles gives lymph its characteristic clear/pale yellow color rather than the red color of blood.

Inflammation is the body's protective response to injury or infection, characterized by redness, heat, swelling, and pain.

Type O blood cells lack both A and B antigens on their surface, which prevents them from triggering an immune response in recipients with A, B, or AB blood types.

Individuals with AB+ blood type are considered universal recipients because they have both A and B antigens on their red blood cells and no antibodies against A or B in their plasma.

Leukemia is a type of cancer that originates in the blood-forming tissues, primarily the bone marrow. It results in the overproduction of abnormal white blood cells.

White blood cells are a key part of the immune system and are responsible for fighting off infections and diseases. Red blood cells carry oxygen, and platelets help with clotting.

In sickle-cell anemia, the hemoglobin mutation causes red blood cells to take on a rigid, sickle-like shape under low oxygen conditions.

Ans - 3

IgG

Monoclonal antibodies

IgM

Thymus

L-chain