Quiz For Lecture 2 - Components Of The Innate Immune System

Explanation
The myeloid lineage includes the granulocytes and agranulocytes, and the Natural Killer Cell which is the only cell of the Lymphoid lineage to play a direct role in the innate immune response.

Explanation
Remember a monocyte is an agranulocyte as it contains few or no granules.
The other agranulocytes are the macrophage and the dendritic cell.

Explanation
A basophil is a type of granulocyte – it has granules within its cytoplasm.
The other granulocytes include the eosinophil, neutrophil and Natural Killer Cell.

Explanation
The complement system of proteins is indeed an effector mechanism of the innate immune system. This system consists of a group of proteins that work together to enhance the immune response against pathogens. It plays a crucial role in inflammation, opsonization (marking pathogens for destruction), and lysis of foreign cells. Therefore, the statement "The Complement system of proteins is an effector mechanism of the innate immune system" is true.

Explanation
The Granulocyte Neutrophil is a type of white blood cell that plays a key role in the immune response to bacterial infections. When there is an infection, neutrophils are recruited to the site and release enzymes and chemicals to destroy the invading bacteria. This process leads to the formation of pus, which is made up of dead neutrophils, bacteria, and tissue debris. Therefore, it is true that the Granulocyte Neutrophil forms the major constituent of pus.

Explanation
Macrophages are found in tissues and phagocytose dead/malfunctioning cells and foreign material.
Also named according to the organ that they are in; microglial cells in the brain, osteoclasts within bone, and kupffer cells when found in the liver.

Explanation
A monocyte circulates in blood, however on leaving blood it is called a macrophage.

Explanation
IL-8 Also produced by the macrophage, this cytokine acts as a chemotracttant, drawing in Neutrophils to the site of infection.
IFN-γ This cytokine is produced by NKC’s and T cells, serving to further activate the mighty macrophage.

Explanation
Dendritic cells function as an antigen presenting cell, phagocytosing infectious agents and traveling to secondary lymphoid organs; and present the antigens of their phagocytosed infectious agents to cells of the adaptive immune system; B & T cells.

Explanation
Macropinocytosis is the process by which the dendritic cell takes up extracellular fluid by endocytosis. This process involves the formation of large, membrane-bound vesicles called macropinosomes, which engulf the fluid and its contents. Macropinocytosis is a non-selective process that allows the cell to sample its environment and capture antigens for presentation to the immune system. Unlike phagocytosis, which involves the ingestion of large particles, macropinocytosis is characterized by the uptake of fluid and small solutes.

Explanation
The Basophil plays a prominent role in mediating the inflammatory response.
It has cytoplasmic granules which contain inflammatory mediators such as histamine and vasodilators such as prostaglandins.

Explanation
The tissue based form of the Basophil is the Mast Cell.

Explanation
Eosinophils are a type of white blood cell that play a crucial role in combating parasitic infections, particularly those caused by helminth worms. They are equipped with granules containing toxic substances that help destroy parasites. Therefore, the statement is true as eosinophils are indeed specialized in fighting against parasitic infections.

Explanation
The Natural Killer Cell (NKC) is the only cell of the lymphoid lineage that plays a prominent role in the innate immune system.
The other cells in the lymphoid lineage, so the B & T cells are the effectors of the adaptive immune system.

Explanation
IL-10 actually switches off NKC activity .
The cytokine IL-2, produced by the T-helper 1 cell, increases the killing ability of the NKC.

Explanation
Langerhans cells are a type of cell whose cytoplasm contains large Birbeck granules and they are similar in function to dendritic cells. Basophils, neutrophils, and monocytes do not have these characteristics and functions.

Explanation
The Complement system is a system of over 20 blood proteins that work together in a cascade to attack extracellular forms of infectious agents. This system plays a crucial role in the immune response by enhancing the ability of antibodies and phagocytic cells to clear pathogens. It can also directly lyse certain pathogens, recruit inflammatory cells to the site of infection, and help in the removal of immune complexes. Overall, the Complement system is an important component of the innate immune system and helps in the defense against infections.

Explanation
C3a is the correct answer because it is the resultant protein from the splitting of complement protein C3. It acts as a chemoattractant, which means it attracts other cells of the immune system to the site of infection. This includes macrophages and neutrophils, which are important for fighting off infections. C3a plays a crucial role in the immune response and helps to recruit the necessary immune cells to the site of infection.

Explanation
The classical pathway is the activation pathway of the complement cascade that is initiated by the binding of antibody to the pathogen's surface. This pathway is specific to adaptive immunity and requires the presence of antibodies. When antibodies bind to the pathogen, they activate complement proteins, leading to a series of reactions that ultimately result in the destruction of the pathogen.

Explanation
The alternative pathway is the correct answer because it is one of the three activation pathways of the complement cascade. It is initiated by the recognition of non-self components on the surface of a pathogen, leading to the activation of complement proteins and the subsequent immune response. The alternative pathway is unique because it can be activated independently of antibodies, unlike the classical pathway.