Innate and Acquired Immunity

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Questions and Answers

What is the primary function of cytotoxic T cells?

To destroy virus-infected cells, tumor cells, or foreign cells (correct)

To potentiate engulfment and killing by phagocytosis

To stimulate B cells to produce antibodies

To suppress the activity of B cells and other T cells

Which type of T cells interacts only with antigen-MHC II complex?

Cytotoxic T cells

T-regulatory cells

T-helper cells (correct)

Regulatory T cells

What is the role of T-regulatory cells in cell-mediated immunity?

To destroy virus-infected cells, tumor cells, or foreign cells

To stimulate B cells to produce antibodies

To potentiate engulfment and killing by phagocytosis

To suppress the activity of B cells and other T cells (correct)

What is the primary function of eosinophils in combating helminths?

To bind to IgE-coated helminths and destroy them Signup and view all the answers

What is the first step in the cell-mediated immunity reaction?

Naïve T cell recognition of cell-associated antigens Signup and view all the answers

Which type of immunity is effective against intracellular pathogens?

Cell-mediated immunity Signup and view all the answers

What is the function of clonal expansion in cell-mediated immunity?

To differentiate T cells into effector cells Signup and view all the answers

What is the final step in the cell-mediated immunity reaction?

Elimination of the microbe or antigen Signup and view all the answers

What type of lymphocytes are responsible for destroying viral infected body cells and abnormal cells that could form tumors?

Natural Killer Cells (NK cells) Signup and view all the answers

Which type of immunity is referred to as 'specific immunity'?

Adaptive immunity Signup and view all the answers

What is the main function of Cell-mediated immunity?

Recognition, attack, and destruction of infected cells Signup and view all the answers

Which of the following is NOT a characteristic of Adaptive immunity?

Provides immediate defense against pathogens Signup and view all the answers

What type of immunity involves the activation of T cells to produce a cell-mediated response?

Cell-mediated immunity Signup and view all the answers

What is the main difference between Cell-mediated immunity and Humoral immunity?

Cell-mediated immunity involves the destruction of infected cells, while Humoral immunity involves the production of antibodies Signup and view all the answers

What is the role of T cells in Cell-mediated immunity?

Recognition, attack, and destruction of infected cells Signup and view all the answers

Which type of cells are involved in Cell-mediated immunity?

T cells and macrophages Signup and view all the answers

What is the characteristic of adaptive immunity?

Antigen dependent Signup and view all the answers

Which type of immunity is provided by vaccination?

Artificial active immunity Signup and view all the answers

What is the function of dendritic cells in the immune response?

Antigen presentation Signup and view all the answers

Which type of cells are involved in cell-mediated immunity?

T lymphocytes and macrophages Signup and view all the answers

What is the characteristic of innate immunity?

Antigen independent Signup and view all the answers

What is the role of natural killer cells in the immune response?

Cytotoxicity Signup and view all the answers

What is the type of immunity that involves the transfer of antibodies from mother to fetus?

Natural passive immunity Signup and view all the answers

What is the type of immunity provided by anti-venom?

Artificial passive immunity Signup and view all the answers

Study Notes

Helminth Immunity

Helminths are too large to be engulfed by phagocytes, and their integument is resistant to microbicidal products of neutrophils and macrophages.
However, they can be killed by histamine, a basic protein present in the granules of eosinophils.
IgE coats the helminths, allowing eosinophils to bind to the IgE and destroy the helminths.

Immunity Classification

Humoral Immunity: mediated by antibodies (B cells), defends against extracellular microbes and microbial toxins.
Cell Mediated Immunity: mediated by T cells, acts against intracellular pathogens.

Cell Mediated Immunity

Composed of T-lymphocytes, responds to intracellular pathogens.
Activated lymphocytes attach to and destroy foreign agents.
Acts when antibodies are ineffective due to inaccessibility to the antigen.

Types of Effector T Cells

Regulatory T cells:
- T-helper cells: interact with antigen-MHC II complex, potentiate engulfment and killing by phagocytosis, and promote growth and differentiation of cells at the immune response site.
- T-regulatory (suppressor) cells: suppress the activity of B cells and other T cells, inhibit antibody production, and suppress the functions of killer T cells and helper T cells.
Cytotoxic (killer) T cells (CD8+): interact with antigen-MHC I molecule, actions mediated by cytokines, lead to destruction of virus-infected cells, tumor cells, or foreign cells.

Cell Mediated Immunity Reaction Steps

Naïve T cell recognition of cell-associated antigens in peripheral lymphoid organs.
Clonal expansion of T cells and their differentiation into effector cells.
Migration of effector T cells to the site of infection or antigen challenge.
Elimination of the microbe or antigen.

Basis of Mode of Development

Active Immunity: lymphocytes produce their own antibodies in response to stimulation by the antigen.
- Artificial active immunity: provided by vaccination.
- Natural active immunity: provided by natural infection.
Passive Immunity: the body receives antibodies from an external source.
- Natural passive immunity: IgG antibody produced in mother crosses the placenta and protects the fetus up to 6 months old.
- Artificial passive immunity: preformed antibodies are injected into the host for immunity (e.g., anti-venom, Rabies vaccine).

Characteristics of Innate and Adaptive Immunity

Innate Immunity: antigen-independent, no time lag, non-specific, no immunologic memory.
Adaptive Immunity: antigen-dependent, lag period, specific, development of memory.

Innate Immunity

Natural Killer (NK) Cells: lyse viral-infected body cells and abnormal cells that could form tumors.
Involved in the internal defense, attracting phagocytes to the infected area.

Acquired/Adaptive Immunity

Acquired Immune System: also referred to as "specific immunity", third line of defense.
Works slowly, involving antigen-specific immune response, recognizing, attacking, destroying, and remembering each pathogen.
Produces specialized cells and antibodies that render pathogens harmless.

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Description

This quiz covers the basics of innate and acquired immunity, including natural killer cells and their role in fighting infected cells and tumours.