ADAPTIVE IMMUNITY Flashcards by Kyra Catedral

ADAPTIVE IMMUNITY
• Characteristics:

• Specificity for individual pathogens
• Ability to remember prior exposures
• Increased response upon repeated exposure

How well did you know this?

Not at all

Perfectly

Adaptive immunity involves

Lymphocytes

How well did you know this?

Not at all

Perfectly

T cells/lymphocytes

Mature in the thymus

Regulatory role

Help B cells respond to antigens

Kill virally infected target cells

How well did you know this?

Not at all

Perfectly

Mature in the bone marrow
Differentiate into plasma cells
Produce antibodies

B cells/lymphocytes

How well did you know this?

Not at all

Perfectly

ADAPTIVE IMMUNITY

Based on clonal selection, expansion, and differentiation of antigen-specific T and B cells

Immunologic Memory

How well did you know this?

Not at all

Perfectly

Results of Immunologic Memory

Greater speed and intensity in response to re-encounter with the same pathogen

Protects host from reinfection

How well did you know this?

Not at all

Perfectly

ADAPTIVE IMMUNITY

Lymphocyte Maturation
• Differentiation starts very early in…..
• Develops specificity and destroys possible…
• Involves well-orchestrated signaling
mechanisms

fetal development

self-reactive cells

How well did you know this?

Not at all

Perfectly

Lymphocyte maturation

• Outcomes:

Creation of a wide variety of antigen-
specific receptors

Selection of helpful cells while avoiding
harmful ones

How well did you know this?

Not at all

Perfectly

T-CELL DIFFERENTIATION

Differentiation occurs in the thymus

• T Cells (60-80%)

How well did you know this?

Not at all

Perfectly

Thymus
Outer cortex and inner medulla
• Early precursors enter the thymus at the_______ and migrate to the_____

cortico-medullary junction

outer cortex.

How well did you know this?

Not at all

Perfectly

Chemokines

Drive migration
Recruit specific cells to particular sites

How well did you know this?

Not at all

Perfectly

T-CELL DIFFERENTIATION

• Precursors committed to becoming T cells
• Undergo gene rearrangement for antigen receptor
• Display distinct surface markers during development

Thymocytes

How well did you know this?

Not at all

Perfectly

T-CELL DIFFERENTIATION
• Thymocytes

• Precursors committed to becoming T cells
• Undergo gene rearrangement for antigen receptor
• Display distinct surface markers during development

How well did you know this?

Not at all

Perfectly

Double-Negative (DN) Thymocytes

• Lack CD4 and CD8 markers

How well did you know this?

Not at all

Perfectly

Gene Rearrangement
• Random gene rearrangement builds diversity
• TCR consists of…

• T-Cell Receptor (TCR)

alpha (a) and beta (B)
chains

How well did you know this?

Not at all

Perfectly

DOUBLE-POSITIVE (DP) STAGE

Express both CD4 and CD8 antigens

How well did you know this?

Not at all

Perfectly

Positive Selection

• Allows only DP cells with functional TCR receptors to survive
• T cells must recognize foreign antigen with MHC molecules
• MHC Restriction
• Selection of thymocytes interacting with host MHC antigens

How well did you know this?

Not at all

Perfectly

DOUBLE-POSITIVE (DP) STAGE
• Negative Selection

Occurs in corticomedullary region and medulla

Eliminates clones capable of autoimmune response

Only 1-3% of DP thymocytes in the cortex survive

How well did you know this?

Not at all

Perfectly

MATURE T CELLS

• CD4 and CD8 Markers

How well did you know this?

Not at all

Perfectly

• CD4 and CD8 Markers
Survivors exhibit only____ marker

one

Wither 4 or 8

How well did you know this?

Not at all

Perfectly

• CD4+ T cells recognize antigen with______

Expressed by 2/3 of peripheral T cells

Thelper cells

class II MHC

How well did you know this?

Not at all

Perfectly

CD8+ T cells interact with antigen and class______

Expressed by 1/3 of peripheral T cells

Cytotoxic T cells

I MHC

How well did you know this?

Not at all

Perfectly

T HELPER CELLS
• Th1 cells produce IFN-v, IL-2, and TNF-
• protect cells against _______by activating cytotoxic lymphocytes and macrophages

intracellular pathogens

How well did you know this?

Not at all

Perfectly

T HELPER CELLS

• Th2 cells produce IL-4, IL-5, IL-6, IL-9, IL-10, and IL-13
• help B cells produce antibodies against ______and to generally regulate
B-cell activity

extracellular pathogens

How well did you know this?

Not at all

Perfectly

T HELPER CELLS Possess CD4 and CD25 5% of all CD4+ T cells Suppress immune response to self-antigens

T Regulatory (Treg) Cells

T HELPER CELLS ***T Regulatory (Treg) Cells*** Possess______ _____of all CD4+ T cells Suppress immune response to self-antigens

CD4 and CD25 5%

______produce_____ Have proinflammatory effect Stimulate growth of hematopoietic cells (mast cells); may promote autoimmune inflammation

Th9 cells IL-9

•_____ cells produce_____ and _____ . Increase inflammation and joint destruction Associated with autoimmune disease

Th17 IL-17 and IL-22

activated by antigens in lymph nodes or spleen

CYTOTOXIC T CELLS (Tc) • CD8+ T cells

• Leave secondary lymphoid tissues, target infection sites • Bind and kill infected cells via apoptosis, antigen-specific • Recognize antigens with class I MHC complexes • Defense against intracellular pathogens, altered host cells (tumor cells)

CYTOTOXIC T CELLS (Tc) • CD8+ T cells

CYTOTOXIC T CELLS (Tc) Mechanisms of Action: Differentiate into_____, proliferate, migrate to affected tissues Kill target cells via: Releasing_____ (granzymes, perforins) Inducing_____ via intracellular signaling

cytotoxic lymphocytes granules apoptosis

Granule-Mediated Killing: Granules contain: _________form pores in target cell membrane ________enter through pores, initiate cascade fragmenting target cell DNA, disrupting mitochondria

Perforins (pore-forming proteins) Granzymes (serine proteases)

activate nuclease, destroying target cell and viral DNA

Granzymes

B CELL DEVELOPMENT • Origin and Initial Development: • B cells originate from _____in the_____. • Mature entirely within the____

hematopoietic stem cells; bone marrow bone marrow

B cell development • The process includes three main phases:

Development of mature immunocompetent B cells Activation by antigen Differentiation into plasma cells for antibody production

The earliest stage requiring direct contact with stromal cells and involving several transcription factors.

Pro-B Cells (progenitor B cells):

B cells Gene Rearrangement: Heavy and light chain genes rearrange create specific antibody molecules. Heavy chains: Light chains: Pro-B cell receptor____ interacts with stromal cell factors to trigger gene rearrangement.

chromosome 14 chromosome 2 and 22 C-Kit

PRE-B CELLS Heavy Chain Synthesis: • Successful rearrangement of heavy chain genes leads to the synthesis of______ and the formation of the____

u chains (IgM class) pre-B cell receptor (pre-BCR)

PRE-B CRLLS • Surrogate Light Chains: u chains pair with surrogate light chains and signaling molecules

Ig-a, Ig-B

PRE-B CELL Clonal Expansion: • Successful pre-BCR signaling triggers clonal expansion. Failure leads to_____.

apoptosis

IMMATURE B CELLS • IgM Expression: • Immature B cells express complete_____ molecules on their surface, indicating successful light chain rearrangement.

IgM

IMMATURE B CELLS Central Tolerance: Self-reactive B cells are eliminated via apoptosis, a process known as… Surviving immature B cells move to the spleen to mature.

central tolerance

MATURE B CELLS Further Differentiation: In the spleen, B cells become_____ or_____ ______remain in the spleen; follicular B cells circulate in secondary lymphoid organs

marginal zone B cells; follicular B cells Marginal zone B cells

Express IgD along with IgM, enhancing antigen recognition

MATURE B CELLS

Lifespan and Activation: Short lifespan unless activated by antigen Activation transforms them into blast cells, then memory cells, and plasma cells

MATURE B CELLS

are large, with abundant cytoplasmic immunoglobulin and an eccentric nucleus.

PLASMA CELLS

PLASMA CELLS • Function:

Their primary role is antibody production. They reside in peripheral lymphoid organs and the bone marrow.

T CELLS Develop in the____ Found in blood (____of circulating lymphocytes), thoracic duct fluid, lymph nodes Identified by_____ formation with SRBCs End products of activation are____ Antigens include_______ Located in____ region of lymph nodes

thymus 60-80% rosette cytokines CD2, CD3, CD4, CD8 paracortical

B CELLS Develop in the_____ Found in_________ Identified by_____ End product of activation is___ Antigens include________ Located in_____ region of lymph nodes

bone marrow bone marrow, spleen, lymph nodes surface immunoglobulin antibody CD19, CD20, CD21, CD40, class II MHC cortical

Monocyte vs Neutrophils

Neutrophils for acute infections Monocytes for chronic infections

What determines the age of Neutrophils

# of lobes

% of Neutrophils

50-70%

Chemical messengers that cause cells to migrate in a particular direction

Chemotaxis

Marginal pool

In the walls of blood vessels Allows neutrophils to move from circulating blood to the tissues

Lifespan of neutrophils in tissue

5 days

Frustrated phagocytes

Eosinophils

Eosinophils are what %

1-3%

Capable of phagocytosis but are much less efficient than NEU because of the smaller numbers present

Eosinophils

Relationship of EO and BASO

Eosinophil is responsible for moderating Basophils’ histamine production It releases antihistamine

During an allergic reaction the first cell to react is the

Basophils

Largest cells in peripheral blood

Monocytes

How is macrophage involved in adaptive immunity

It present antigens to T and B cells. These cells will study the anatomy of the bacteria so that on the next exposure, the IS can readily fight

Basophils vs Mast cells

Both came from the bone marrow but Basophils stays in the blood vessels whereas Mast cells are segregated in the skin No basophils in tissue Sometimes, mast cells can be seen in blood (rare)

More potent during allergic reaction? Why?

Mast cells Bigger and contains more histamines. First responders during infections

Most potent allergic cell Most potent phagocytic cell

Mast cell Dendritic cell

Macrophages can only eat

Bacteria

MHC

Major Histocompatibility complex

Cytotoxic action

Produce perofrins and granzymes

Unsa gina indicate if may antibody naka dikit sa cell

Most likely the cell is infected. Nk cell will attach to the Fc region (Fab attaches to the antigen)

Thymosin

promotes the maturation of T-cells (a type of white blood cell) within the thymus. T-cells are essential for adaptive immunity, which is the body's ability to recognize and remember specific pathogens.

Positive vs Negative Selection

Positive Selection: Thymocytes that can moderately bind to self-major histocompatibility complex (MHC) molecules survive. This ensures that the T-cells can recognize antigens presented by MHC molecules. Negative Selection: Thymocytes that bind too strongly to self-antigens are eliminated to prevent autoimmunity. This process ensures that the mature T-cells are self-tolerant.

Class I MHC found in

All nucleated cells

Class II MHC found in

Antigen presenting cells (ability to phagocytose)

Th1 cells protect cells against Th2 cells protect cells against

Intracellular pathogens Extracellular pathogens

Potent for tumor

Cytotoxic Tcells

ADAPTIVE IMMUNITY Flashcards

(75 cards)