Question

Below are descriptions of different steps in the immune response. Each description has an associated letter. Use the letters to answer the questions below matching each question with the best answer. Note, only use each letter once in answering the questions.

A. Phagocytosis of the pathogen

B. Memory B cells recognizing an antigen and activating a secondary immune response

C. Release of interferons from an infected cell that activates apoptosis of nearby cells

D. Antigen-presenting macrophage interacts with a helper T cell

E. Plasma cells producing antibodies specific to an antigen

Which is the first step in the innate immune response activating the adaptive immune response?

Which step will occur after an individual has developed immunity to a specific pathogen?

Which step occurs directly after a macrophage recognizes a pathogen through interaction with antigens on the surface of the pathogen?

Which statement describes what B cells mature into after activation by a T cell?

Which step describes an innate immune response to viral pathogens?

Answer 1

Immune response is initiated when; the body encounters any foreign molecules acting as exogenous or endogenous antigens).

The innate immunity or non-specific immunity acts as the first line of defense, provides barrier against the foreign substances.

Various cytokines released from specific cells, like interleukins (IL), tumor necrosis factor alpha (TNFα), activates the production of mature phagocytic cells, like neutrophils, macrophages and dendritic cells and induce their migration to the site of infection or invasion.

Phagocytic cells engulf the foreign substances by phagocytosis or endocytosis.

• The phagocytosed molecules processed and, then the peptide fragments of antigens are expressed through membrane bound glycoproteins called major histocompatibility complex (MHC).
• The antigenic polypeptide bound to MHC molecules further induces B-lymphocytes (designated from Bursa of Fabricus in birds, in humans generated in bone marrow) and T-lymphocytes (lymphocytes maturing in thymus), generating humoral or cell mediated immune responses, as well as immunogenic memory. Such specific activations lead to clonal selection, clonal expansion and clonal deletion.
• T cytotoxic cells recognizes type I MHC molecules bound antigenic peptides, and co-stimulatory responses. They contribute to the cell mediate immunity. Tc , then differentiates into memory cells and effector cells called cytotoxic T-lymphocytes (CTLs). CTLs then further recognizes MHC-I complexes bound to the target cell, and thus destroy the target cell.
• B-cells differentiate into memory B-cells and effector B cells (or plasma cells). Plasma cells release antibodies. Antibodies, released to the plasma, tissue fluid and lymph, contribute to humoral immunity.

1. The first step in the innate immune response activating the adaptive immune response- A

2. Step will occur after an individual has developed immunity to a specific pathogen- B

3. Step occurs directly after a macrophage recognizes a pathogen through interaction with antigens on the surface of the pathogen- E

4. Statement describes what B cells mature into after activation by a T cell- D

5. Step describes an innate immune response to viral pathogens- C