Problem 13 - Biology Today and Tomorrow with Physiology

Question

Match the immune cell with a description. $$\begin{array}{cc}\text{______mast cell} && \text {a. kills virus-infected cells}\end{array}$$ $$\begin{array}{cc}\text{______ B cell} && \text {b. targets parasitic worms}\end{array}$$ $$\begin{array}{cc}\text{______ helper T cell} && \text {c. activates cytotoxic T cells}\end{array}$$ $$\begin{array}{cc}\text{______ NK cell} && \text {d. kills cancer cells}\end{array}$$ $$\begin{array}{cc}\text{______ cytotoxic T cell} && \text {e. factor in allergic reactions}\end{array}$$ $$\begin{array}{cc}\text{______ dendritic cell} && \text {f. antigen- presenter}\end{array}$$ $$\begin{array}{cc}\text{______ eosinophil} && \text {g. makes antibodies}\end{array}$$

Step-by-Step Solution

Answer

Mast cell: e, B cell: g, Helper T cell: c, NK cell: d, Cytotoxic T cell: a, Dendritic cell: f, Eosinophil: b.

Step 1: Match Mast Cell

Mast cells play a significant role in allergic reactions by releasing histamine causing inflammation. Therefore, the correct match is e: factor in allergic reactions.

Step 2: Match B Cell

B cells are responsible for the production of antibodies as part of the adaptive immune response. Hence, the correct match is g: makes antibodies.

Step 3: Match Helper T Cell

Helper T cells provide assistance in the immune system by activating cytotoxic T cells and other immune responses. Therefore, the match is c: activates cytotoxic T cells.

Step 4: Match NK Cell

Natural Killer (NK) cells are key players in the innate immune system known to kill virus-infected and cancer cells. Thus, the correct match is d: kills cancer cells.

Step 5: Match Cytotoxic T Cell

Cytotoxic T cells directly attack virus-infected cells and tumor cells. Thus, the correct match is a: kills virus-infected cells.

Step 6: Match Dendritic Cell

Dendritic cells are antigen-presenting cells that show antigens to T cells, initiating an immune response. Therefore, the correct match is f: antigen-presenter.

Step 7: Match Eosinophil

Eosinophils are involved in combating multicellular parasites and certain infections, as well as in modulating allergic inflammatory responses. Hence, the match is b: targets parasitic worms.

Key Concepts

Mast Cells

Mast cells are a vital component of the immune system with a special role in allergic reactions. These cells are found in connective tissues throughout the body, particularly under the skin, lining of the stomach, and intestines. When an allergen enters the body, mast cells release granules containing histamine and other chemicals.

This release leads to inflammation and other allergic symptoms like itching and swelling. Mast cells are equipped with receptors for immunoglobulin E (IgE) antibodies, which make them highly sensitive to allergens.

• Mast cells play a role in wound healing and defense against pathogens.
• Their dysfunction or over-activation can lead to severe allergies or conditions like mastocytosis.

B Cells

B cells are a crucial part of the adaptive immune system, primarily responsible for antibody production. These cells originate in the bone marrow and mature into different forms to perform their functions. Once activated by an antigen, B cells can differentiate into plasma cells.

Plasma cells produce antibodies specifically designed to neutralize or destroy the pathogen. B cells can also develop into memory cells that "remember" pathogens.

• B cells contribute to long-term immunity and are key players in vaccines.
• They are also involved in autoimmune disorders where the immune system mistakenly targets healthy tissues.

Helper T Cells

Helper T cells are central to the immune response coordination. They don't directly attack pathogens but support other immune cells like B cells and cytotoxic T cells. Helper T cells recognize antigens presented by antigen-presenting cells, like dendritic cells.

Once they recognize an antigen, they secrete cytokines that enhance the immune response, activating cytotoxic T cells to kill infected cells.

• Helper T cells are subdivided into various types, each specializing in different immune functions.
• A loss of these cells can severely compromise the immune system, as seen in HIV/AIDS.

Cytotoxic T Cells

Cytotoxic T cells are the immune system's "hitmen." Their main job is to directly destroy virus-infected cells and tumor cells. They recognize antigens presented on infected or abnormal cells and release substances that induce apoptosis, or programmed cell death.

This process is vital in controlling viral infections and preventing the spread of tumors.

• Cytotoxic T cells are part of the adaptive immune system, requiring specific signals to become fully activated.
• An imbalance in their activity can lead to tissue damage or autoimmune diseases.

Dendritic Cells

Dendritic cells act as messengers between the innate and adaptive immune systems. They are known as "antigen-presenting cells" because they capture antigens and present them to T cells, setting off the adaptive immune response.

They are found in tissues in contact with the external environment, such as the skin and the lining of the nose, lungs, and digestive tract.

• Dendritic cells play a critical role in maintaining immune tolerance to self-antigens.
• They are used in cancer immunotherapy to help educate the immune system to target tumor cells.

Eosinophils

Eosinophils are a type of white blood cell involved in fighting off parasitic infections and playing a role in allergic reactions. They are often found in the digestive tract and are known for their role in combating multicellular parasites like worms.

Eosinophils also contribute to the pathology of allergic diseases, such as asthma and hay fever.

• They release enzymes and toxic proteins to destroy parasites and pathogens.
• High eosinophil counts can be an indicator of parasitic infections or allergies.