The rest of the above tissues except A are peripheral lymphoid tissues. Thymus and bone marrow are central lymphoid tissues.

Humoral immunity, such as memory B cells and antibodies, are types of specific immunity (adaptive immunity).

Macrophage, dendritic cells, and neutrophiles are major phagocytic cells. Eosinophils are minor phagocytic cells. Basophils secrete histamine and anticoagulant heparin to damaged tissues or allergic reactions.

IgD, IgE, and IgG have a monomer shape. IgM has a pentamer shape and IgA has a dimer shape.

The plasma cell derived by the B cell proliferates antibodies.

Two line shapes, which are α and β chains connected by one disulfide bridge, is the structure of the T cell receptor. Y shape and two light and heavy chains linked by four disulfide bridges are the structure of the B cell receptor.

Without helper T cells, the production of B cells and cytotoxic T cells would not increase. This results in a deficiency of memory B cells, plasma cells, antibodies, and cytotoxic T cells.

Class I MHC molecules are presented on the surface of most cells or infected cells. Class II MHC molecules are presented on the surface of macrophage to be identified by helper T cells. Perforin is secreted by cytotoxic T cells to kill infected cells and antibodies are made by plasma cells to bind antigen.

The epitope is called an antigenic determinant, and is bound by antibodies. CD8 at cytotoxic cells binds class I HMC molecules. CD4 at helper T cells binds class II HMC molecules. Cytokines are proteins secreted by immune cells to activate lymphocytes.

B cells are maturated at bone marrow and T cells are maturated at the thymus. Spleen is the site for filtering or destruction of red blood cells. Lymph nodes are the place for filtering bacteria or foreign matter.

Erythroblastosis fetalis happens when the Rh⁺ father and Rh^– mother have an Rh⁺ fetus. The Rh⁺ blood type can receive an Rh^– blood transfusion but the Rh^– blood type cannot receive an Rh⁺ blood transfusion. The Rh^– mother of the fetus produces antibodies when the mother accepts the Rh⁺ blood from the fetus. The fetus could die from accepting the mother’s antibodies.

Lymph nodes filter bacteria or foreign particles. Secretion of thymosin hormone happens in the thymus.

Correct process of healing of the local inflammation:

Releasing of histamine → Movement of antimicrobial proteins and clotting elements to the injury site → Blood clotting and phagocytes → Healed tissue 

The above picture is IgM produced after the first exposure to an antigen. IgM is very useful in complement activation. The most common antibody in blood is IgG, and the import antigen receptor on B cells is IgD. Newborn immunity and localized defense of mucous membranes are IgA.

The B cell receptor consists of four chains (two heavy chains and two light chains) connected by four disulfide bridges.

In cell-mediated immunity, cytotoxic T cells derived from helper cells produce memory cytotoxic T cells and active cytotoxic T cells. Cytotoxic T cells secrete perforin molecules to infected cells.

All are correct statements except II. Antibiotics can kill or hinder the growth of micro-organism such as bacteria, protozoans, or fungi. However, antibiotics do not work as an inhibition agent of viruses.

Memory B cells and plasma cells (effector cells) are derived from B cells. Memory B cells are long-lived cells. Plasma cells are short-lived cells and combat the same antigen.

B blood type produces anti-A antibodies and can receive a transfusion only from B and O blood types.

Natural or artificial infections agents, such as vaccinations, confer active immunity. Introducing antibodies from others confers passive immunity.

IgE, a monomer type, functions in allergic reactions.

In humoral immunity, B cells derived from helper T cells produce memory B cells and plasma cells. Plasma cells proliferate antibodies. Cytotoxic T cells destroying infected cells are involved in cell-mediated immunity.

All are correct.

The secondary immune response is of greater magnitude than the primary response. The primary immune response involves proliferating antibodies by B cells, activating cytotoxic T cells, and becoming sick.