Immunology: Adaptive Immunity, Immunoglobulins & Vaccination

These flashcards cover key concepts related to adaptive immunity, immunoglobulins, and vaccination as discussed in the lecture.

What are the two main types of immune response to foreign antigens?

Non-specific response (innate) and specific response (adaptive).

What is the purpose of non-specific defense mechanisms?

To prevent the spread of infection until specific mechanisms can take over.

What are the three types of cells involved in cell-mediated immunity?

T-lymphocytes, natural killer cells, and macrophages.

What is another name for antibody-mediated immunity?

Humoral mediated immunity.

How long may it take for lymphocytes to become activated?

3 to 4 days.

Where do T-lymphocytes develop from?

Lymphoblasts in the red bone marrow.

What happens to immature T-lymphocytes after they leave the bone marrow?

They migrate to the thymus gland to develop immunological competence.

What percentage of T-cells typically fail the competence test in the thymus?

95%.

What molecules recognize antigens on T-lymphocytes?

T-cell receptors (TCR).

What do antigen presenting cells (APCs) do?

Phagocytose and destroy antigens, presenting fragments on their membranes.

What is the function of the MHC complex in relation to T-cells?

It links antigen fragments and presents them to T-cells for activation.

Which T-cell is activated by a specific foreign antigen-MHC complex presented by an APC?

Helper T-cell (TH cell).

What is clonal expansion?

The process where an activated TH cell divides to produce several clones of itself.

What are the four major T-cell subsets?

Cytotoxic T-cells (Tc), Helper T-cells (Th), Suppressor T-cells, Memory cells.

What do cytotoxic T-lymphocytes recognize and destroy?

Cells with foreign antigens, including infected cells and cancer cells.

What cytokines do Helper T-cells primarily release?

Interleukin-2 and Interleukin-4.

What do activated B-cells differentiate into?

Plasma cells and memory cells.

What is the role of plasma cells?

To produce and release antibodies.

Where do B-lymphocytes primarily reside once activated?

In lymphoid tissues, such as lymph nodes and spleen.

What do B-cell receptors (BCR) do?

Recognize specific antigens.

What happens during B-cell activation by TH cells?

TH cells secrete cytokines that stimulate B-cells to divide and differentiate.

What are the characteristics of memory B-cells?

They persist for many years and respond quickly upon re-exposure to the same antigen.

What are immunoglobulins?

Highly specific proteins involved in the immune response.

How many polypeptide chains is each immunoglobulin made up of?

Four polypeptide chains: two heavy chains and two light chains.

What differentiates the constant region and the variable region of immunoglobulins?

The constant region (Fc) interacts with immune cells, while the variable region (V) binds to specific antigens.

What is the role of IgG in the immune system?

It binds to macrophages and neutrophils, effective against bacteria, viruses, and can cross the placenta.

What does IgM primarily induce in the immune response?

Primary response to pathogens and agglutination of antigens.

What type of antigens does IgA protect against?

Viral and bacterial antigens through body secretions.

What does IgE mediate in the immune system?

Allergic responses and protection against parasitic infections.

What distinguishes a primary immune response from a secondary immune response?

The secondary response is faster and stronger due to memory cells.

What is the significance of memory cells after the first exposure to an antigen?

They allow for a rapid response upon subsequent exposures to the same antigen.

What types of antigens may be used in vaccinations?

Killed pathogens, attenuated pathogens, non-pathogenic strains, coat proteins, or altered bacterial toxins.

How does vaccination contribute to long-term immunity?

By generating memory cells and antibodies without introducing the active pathogen.

What is the typical time frame for a primary immune response?

3 to 14 days.

What happens during a secondary immune response?

A rapid and robust reaction due to pre-existing memory cells.

What can cause the need for annual vaccinations?

Continual mutation of viruses like cold and influenza changing surface antigens.

Why are some viruses difficult to vaccinate against?

Because they mutate frequently, making it hard to target with a stable vaccine.

What is the role of T-cell subsets in the immune response?

They perform distinct functions, such as direct killing of infected cells or enhancing the B-cell response.

What critical role do cytokines play in immune system communication?

They signal and regulate interactions between immune cells.

How are B-cells activated by TH cells?

Through recognition of an antigen-MHC complex and cytokine signaling.

What happens to B-cells after they are activated and proliferate?

They differentiate into plasma cells or memory B-cells.

What primarily defines the effectiveness of immunoglobulin subclasses?

Their location and the types of pathogens they target.

In what area of immune function does the variable region of antibodies play a crucial role?

In the specificity of binding to particular antigenic regions.

What anatomical structures are essential for the maturation of T-lymphocytes?

Thymus gland and lymph nodes.

What is the significance of antigenic epitopes in relation to antibodies?

Different antibodies can recognize the same antigen at different sites.

What is the status of T-cells after their activation?

They leave lymph nodes to attack infected tissues.