bio immunology exam 1

What cells differentiate into macrophages and erythrocyte (RBC)?

Monocytes; erythrocyte progenitor

Which cells are the main phagocytes of the innate immune system?

Macrophages, neutrophils

Regarding pathogens: What is the function of the mucus and cilia in the respiratory tract?

Mucus trap the pathogens preventing them to adhere to the epithelium and the cilia beating moves outward the mucus with pathogen

How does the body defend itself after a pathogen has breached the first physical barrier of the body’s surface?

Antimicrobial substances and innate immune cells will attempt to eliminate the pathogen

Lysozyme plays a role in the antimicrobial

chemical defenses. How does lysozyme exert its effects on Gram-positive bacteria?

Lysozyme digest the peptidoglycan layer of bacterial walls, exposing the cell membrane to other antimicrobial agents.

Macrophages express receptors for many microbial constituents PRRs.

What TLR stands for:

What TLR-4 detects on the gram-negative

bacteria?

Toll-Like receptors

TLR-4 detects (recognizes) LPS of gram-negative

bacteria

Which cell types differentiate from a common lymphoid progenitor?

B cells, T cells, NK cells, ILC

Which cells of adaptive immunity are responsible for humoral immunity?

B cells

What is the main role of cytotoxic T lymphocytes ?

Kill infected cells or altered self-cells

What is the main function of a T-cell

receptor? TCR

Recognizes a specific Ag presented via an MHC cell-surface

complex from an antigen-presenting cell (APC)

CD8+ T cell: TCR recognizes peptide-MHC I also on infected

nucleated cells, not necessarily APCs.

DC4+ helper cell: TCR recognizes peptide-MHC II

What are the four main roles of helper T lymphocytes ?

Help B cells; activate macrophages; support CD8⁺ cytotoxic T-cell

response; release cytokines

After B-cell clonal expansion, activated B cells rapidly divide to produce a large population of genetically identical daughter cells, collectively referred to as clones.

What happens to these cells afterward?

The B cells then differentiate into plasma cells

(antibody-secreting) and long-lived memory

cells

What type of hypersensitivity reaction primarily involves mast

cells and histamine release?

Type I

What is the primary lymphoid organ?

bone marrow, thymus

What is the mechanism of Type

I hypersensitivity? Example.

IgE-mediated immune response to allergens

Ag-specific IgE binds to mast cells and basophils,

triggering the release of histamine, tryptase, and

proteases.

Pollen, dust mites (asthma, hay fever (allergic

rhinitis), anaphylaxis)

What are the five biological response of body tissues during an inflammation process. Briefly describe them

Heat, redness, swelling: vasodilation and increased

vascular permeability; leaked of fluid into tissue.

Tenderness and pain: inflammatory cells migrate

into tissue, releasing inflammatory mediators that

cause tenderness and pain

A bacterium has crossed an epithelial barrier and is multiplying in extracellular fluid. Antibodies may or may not already be present.

What could complement proteins do to help?

Tag the microbes for phagocytosis

Recruit defense cells to the site of infection

Damage the microbial membrane through membrane attack complex

What is the main function of MHC molecules in

the immune system?

To present antigens (peptides) to T lymphocytes

Which MHC class presents endogenous antigens and interacts with CD8⁺ T cells?

Where this MHC class can be found (cells)

MHC class I

Almost all nucleated cells

On which cells are MHC class II molecules normally expressed? examples of these cells

Antigen presenting cells (APCs) such as

dendritic cells, macrophages, and B

cells.

the MHC class II present exogenous antigens and

interact with what T cell and co-receptor?

MHC class presents exogenous antigens and interacts with CD4⁺ T cells

What is the main role of T follicular helper cells?

Tfh cell → recognizes peptide–MHC II on B cell → provides

B-cell help (activation, proliferation, differentiation into

plasma cells → antibody response

Which complement pathway is activated when antibodies bind to antigens on a pathogen surface?

Classical pathway

What is the key molecule common to the three complement pathways where activation converges

C3 convertase

C3 is cleaved into C3a and C3b in all three

pathways

Which molecules initiate the Lectin pathway by

recognizing specific carbohydrate patterns on

pathogens?

Manose-biding lectin (MBL) or ficolins

In the Alternative Pathway, what fragments

combine to form the C3 convertase

C3b+Bb = C3bBb

List the sequence of complement components that form the Membrane Attack Complex (MAC) and describe its function.

C5b, C6, C7, C8, and multiple C9 molecules

assemble to form the MAC, which creates

pores in target cell membranes leading to cell

lysis.

Which complement pathway is related to the

adaptive immunity?

The Classical Pathway is often called the

"antibody-dependent pathway" because its

activation requires the presence of

antibodies, the key effector molecules of the

adaptive immune system

A patient has recurrent severe Neisseria infections.

Testing shows a deficiency in C8. Which complement outcome is most directly

impaired?

Terminal complement: Membrane attack

complex - MAC

Which is the most potent anaphylatoxin fragment of a

complement protein that causes smooth muscle

contraction and vascular permeability?

C5a fragment is the most potent anaphylatoxin

fragment of complement protein

cytokines refer to as

large group of proteins

What causes the formation of a tertiary lymphoid tissue in rheumatoid

arthritis?

Failure in the production of B and T lymphocytes

primary lymphoid organ?

thymus

Where in the thymus do the T cells mature

into Tc and Th cells?

Medulla

main function of the lymph nodes?

Filtering lymph and initiation immune responses

Where does the maturation of B lymphocytes primarily occur?

Bone marrow

Which statement best describes the

composition of lymph?

fluid that leaked from capillaries into

interstitial space rich in lymphocytes

best describes the

pathway of lymph flow?

From lymph vessels to subclavian veins

What is the primary function of Mucosal-associated

Lymphoid Tissue (MALT)?

Detecting and responding to pathogens at mucosal

surfaces

Peyer’s patches, which are part of MALT, are

located in

small intestine

The white pulp of the spleen is primarily

involved in:

Red blood cell destruction

Which part of the spleen is responsible for

filtering and removing damaged or old red blood

cells?

capsule

which cell types differntiate from a common lymphoid progenitor

B cell, T cell, NK cell, and ILC

what cells differeniate into macrophages

monocytes

what describes the primary role of neutrophils during an acute bacterial infection

phagocytose and destroy invading microorganisms

which immune function is most strongly associated with eosinophils

defense against helminth parasites (allergic reactions)

why are dendritic cells important for connecting innate and adaptive immunity

they recognize antigens and present them to naive T cells

The immune system is divided into two groups

Can you identify the names of these two types?

innate & adaptive

specific immunity

Subsequent exposure to the same foreign organism induces a memory response

Main sensors for Ag and communicator with

other immune cells?

dendritic cells -DCs

PRRs

PRRs detect/recognize PAMPs

PAMPs

Pathogen-associated molecular patterns: imple molecules and regular pattern of structure

TLR-1 + TLR-2

microbial components of bacteria

TLR-2

bacteria, fungal and viral components

TLR-4

LPS of gram- bacteria (initiate inflammation – response to bacterial infectionn

Manose receptor (CD206)

binding, endocytosis, Ag presentation of bacterial, fungi, viruses.

NOD (nucleotide-binding oligomerization domain

receptors)

detect intracellular bacterial components.

Dolor (Pain)

release of chemicals that stimulate nerve endings

Afferent Lv

drain into node

Efferent Lv

lymph leaves

spleen

Largest secondary lymphoid organ

MHC class I

nucleated cells;Present endogenous peptides to responding responding CD8+ Tc

cells

MHC Class II

APCs (macrophages, DCs) ;Process exogenous peptides for presentation to CD4+ Th cells

MHC molecules

body cells recognize infected and cancerous cells.

Tc cells

stimulate B cells

Th1

activate macrophages

Th2: (ILs)

defend against extracellular pathogens; stimulate B cells

Tfh

recognize Ags on B cells - activating them = Ab-producing plasma cells.

2 key properties of hematopoietic stem cells

Self-renewal: the ability to generate additional stem cells.

Differentiation: the capacity to produce more specialized cell types.

myeloid lineage

granulocytes (neutrophils, eosinophils, basophils), monocytes/macrophages,

dendritic cells, mast cells, megakaryocytes/platelets, and erythrocytes

first line of defense

innate immune system

complement system

target pathogens (lysis, phagocytosis)

Keratinocytes

barrier constantly renewed = make it hard for infections to settle.

Stratum granulosum (waterproof lipid layer)

antimicrobial peptides and proteins (chemicals): against invasion.

lectin

Microbial carbohydrates

what is the secondary lymphoid organ

spleen, lymph nodes. Peyer’s patch, mucosal lymphoid tissue

what is the tertiary lymphoid organ

special secondary: happens in chronic inflammation