NK cells kill target cells that:

Lack MHC 1

Which molecule is an anaphylatoxin?

C5a

Interferon-α is primarly produced in response to:

Viruses

Defensins are:

Antimicrobial peptides

The oxidative burst in neutrophils requires:

NADPH oxidase

Which is a professional antigen-presenting cell?

Dendritic cell

Mannose-binding lectin activates which complement pathway?

Lectin

The major function of macrophages is:

Phagocytosis and cytokine release

Which cytokine activates macrophages?

IFN-γ

Which cell type produces type I interferons?

Virus-infected cells

Which receptor recognizes LPS on gram-negative bacteria?

TLR4

Which cells forms pus?

Neutrophils

C-reactive protein (CRP) promotes:

Opsonization

Which chemokine attracts neutrophils?

IL-8

Dendritic cells migrate to lymph nodes via:

Lymphatic vessels

Which complement pathway is antibody-dependent?

Classical

Which immune cells release major basic protein?

Eosinophils

Which organ filters bloodborne pathogens?

Spleen

Which cytokine causes septic shock?

TNF-α, due to massive vasodialation

Which cell bridges innate and adaptive immunity?

Dendritic cell

Which cell is most effective in killing helminths?

Eosinophils

Which innate cell presents antigen via MHC II?

Macrophages

What do PRRs (pattern recognition receptors) detect?

PAMPs (pathogen molecular patterns)

Which complement protein is most important for opsonization?

C3b

Which cells kill virally infected cells without prior sensitization?

NK cells

What triggers the alternative complement pathway?

Pathogen surfaces

Which molecule mediates leukocyte rolling?

Selectins

What is the main component of NETs (neutrophils extracellular traps)?

DNA

What is a pro-inflammatory cytokine?

IL-6

Acute phase proteins are produced by the:

Liver

Which innate cell presents lipid antigens on CD1 molecules?

Dendritic cells

IFN-γ is produced mainly by:

NK cells and T cells

Which cells release histamine in response to C3a and C5a?

Mast cells

Which phagocyte is long-lived?

Macrophage

Which cells produce antibodies?

B-cells that differentiate into Plasma cells

CD8+ T cells recognize antigen presented on:

MHC I

Which antibody is produced first in a primary response?

IgM

Which enzyme mediates V(D)J recombination:

RAG1/2

Which antibody class crosses the placenta?

IgG

T-cell maturation occurs in the:

Thymus

Class-switch recombination requires which enzyme?

AID

Th1 cells activate:

Macrophages

Th2 cells activate:

Eosinophils for parasites/allergies

IgA is most associated with:

Mucosal immunity

Which immunoglobulin is pentameric?

IgM

MHC II presents peptides from:

Extracellular proteins

Which cells activate naive T cells?

Dendritic cells

Which cytokine is key for Th17 differentiation?

IL-6

Regulatory T (Tregs) cells suppress immunity using:

IL-10 and TGF-β

Memory B cells allow for:

Faster and stronger response

Somatic hypermutation occurs in the:

Germinal center

Which molecule provides costimulation (secondary activation signal) to T-cells?

CD80/86

Affinity maturation increases:

Antibody binding strength

Anergy (T-cell unresponsiveness) results from

Lack of costimulation

Which cells kill virus-infected cells in adaptive immunity?

CD8+ T cells

Thymic positive selection ensures T cells:

Can bind self-MHC

Thymic negative selection eliminates T cells that:

Bind foreign antigens

Which cytokine is essential for T-cell proliferation?

IL-2

Which antibody neutralizes toxins?

IgG

CD4 binds to:

MHC II β2 domain

what is an epitope?

The specific part of antigen recognized by antibodies

Cross-presentation allows dendritic cells to present:

Extracellular antigens on MCH I

IL-4 promotes which antibody isotype?

IgE

CD28 on T cells binds to:

CD80 and CD86

Which antibody is associated with allergic reactions?

IgE

Naive B cells express:

IgM and IgD

Which cytokine drives Th1 differentiation?

IL-12

Th17 cells are important for defense against:

Extracellular bacteria and fungi

Which cells are essential for germinal center formation?

T follicular helper cells

Which processes require AID?

Class switch & somatic hypermutation

IgG is most effective in:

Neutralization and opsonization

What is clonal selection?

Expansion of lymphocytes that bind antigen

What cytokine activates CD8+ T cells?

IL-12

What is central tolerance?

Elimination of self-reactive lymphocytes in thymus/bone marrow

Which cell type kills cells via perforin and granzyme?

CD8+ T cells

What is required for T-cell activation?

Antigen + costimulation

What is peripheral tolerance?

control of self-reactive cells outside primary organs

which isotypes can activate complement?

IgM and IgG

what is the purpose of the thymus?

T-cell development

T-cell receptor recognizes:

Peptide-MHC complexes

Which antibody is dimeric in secretions?

IgA

Which T cells help activate B cells?

Tfh (follicular helper) cells

Which cytokine inhibits immune responses?

IL-10

Plasma cells primarily reside in the:

Spleen and lymph nodes

Type I hypersensitivity reactions are mediated by:

IgE

Anaphylaxis is an example of:

Type I

Type II hypersensitivity involves:

IgG/IgM binding to cell surfaces

Serum sickness is which type of hypersensitivity?

Type III

Contact dermatitis is mediated by:

T cells

Graves disease is caused by antibodies that:

Stimulate TSH receptors

Myasthenia gravis results from antibodies that:

Block acetylcholine receptors

Immune complexes deposit in tissues in which hypersensitivity?

Type III

Tuberculin skin testing is:

Type IV

Rheumatoid arthritis is mainly:

Type III and IV

Which hypersensitivity involves complement activation on cell membranes?

Type II

Lupus is primarliy associated with:

Immune complex deposition

Anti-dsDNA antibodies are found in:

Systemic lupus erythematosus

Hashimoto thyroiditis involves:

Antibody-mediated thyroid destruction

Goodpasture syndrome targets which tissues?

Kidney and lungs

Type IV hypersensitivity occurs after:

Days

Autoimmunity may result from:

Loss of self-tolerance

Celiac disease is caused by T-cell response to:

Gluten

Molecular mimicry occurs when:

Pathogen antigens resemble human proteins

Which cytokine drives chronic autoimmune inflammation?

TNF-α

Which hypersensitivity features wheals and flares?

Type I

Hemolytic transfusion reactions are:

Type II

Immune complex deposition in glomeruli indicates:

Type III

Multiple sclerosis affects the:

Myeline of CNS

Autoantibodies against intrinsic factor cause:

Pernicious anemia

Atopic asthma is mediated by:

IgE

Chronic transplant rejection is mediated by:

T-cells and macrophages

Which hypersensitivity is mediated ONLY by T cells?

Type IV hypersensitivity

Anti-CCP (cyclic citrullinated peptide) antibodies appear in:

Rheumatoid arthritis

What cell types drives Type IV hypersensitivity?

CD4+ T cells

Immune thromocytopenic purpura (ITP) is:

Type II

Asthma is associated with increased:

IgE

Guillain-Barre Syndrome (GBS) is triggered by:

Molecular mimicry

Autoimmune hemolytic anemia is mediated by:

Antibodies against RBCs

What mediates damage in Type III hypersensitivity?

Immune complexes

Epitope spreading refers to:

Broader autoreactive responses over time

Which hypersensitibity uses Fc receptors on macrophages?

Type II hypersensitivity

What drives granuloma formation?

Th1 cells

Which illness is associated with anti-histone antibodies?

Drug-induced lupus

Food allergies are:

Type I hypersensitivity

Autoimmune disease more common in women because of?

Hormonal and genetic factors

HLA-B27 is associated with:

Ankylosing spondylitis

PPD (purified protein derivative) test is a:

Type IV, tests for TB

Stevens-Johnson syndrome involves:

T-celll mediated cytotoxicity

In Type II hypersensitivity complement leads to:

Tolerance

Autoimmune disease often involve elevated:

IL-6

Pemphigus vulgaris involves antibodies against:

Desmosomes

Vasculitis in Type III hypersensitivity results from:

Immune complexes

Chronic autoimmune diseases often involve:

Macrophages and Th1 cells

Autoimmune diseases commonly involve:

Loss of self-tolerance

X-linked agammaglobulinemia involves failure of:

B-cell maturation

ADA (Adenosine Deaminase) deficiency leads to:

SCID (Severe Combined Immune Deficiency)

DiGeorge syndrome results from failure of:

Thymus

Chronic granulomatous disease is caused by defective:

NADPH oxidase

Complement C5-C9 deficiency leads to infections with:

Neisseria

Selective IgA deficiency cause:

Mucosal infections

Hyper-IgM syndrome results from failure of:

Class-switching

Wiskott-Aldrich syndrome includes:

Eczema infections thromocytopenia

SCID patients lack:

Both T and B cells

Splenectomy increases risk of infection by:

Encapsulated bacteria

HIV infects:

CD4+ T cells

Leukocyte adhesion deficiency affects:

Integrins

C3 deficiency increases susceptibility to:

Encapsulated bacteria

X-linked agammaglobulinemia (XLA) presents with:

Low all immunoglobulins

HIV reduces immunity by:

CD4 T-cell destruction

Ataxia-telangiectasia involves:

DNA repair defects

Chronic mucocutaneous candidiasis results from defective:

T-cell response

Job syndrome (Hyper-IgE) causes:

High Ige and eczema

Complement C1 inhibitor deficiency causes:

Hereditary angioedema

Neutropenia increases susceptibility to:

Bacterial infections

NK cell deficiency leads to:

Viral infections

Hyper-IgM syndrome is due to:

CD40L deficiency

SCID patients require:

Bone marrow transplant

People without a spleen lack:

Marginal zone B cells

HIV binds to:

CD4 and CCR5/CXCR4

Hyper-IgE syndrome results in impaired:

Neutrophil chemotaxis

Paroxysmal nocturnal hemoglobinuria results from:

Complement overactivation

Patients with MCH II deficiency lack:

CD4 T-cell activation

Chronic granulomatous disease leads to susceptibility to:

Catalase-positive bacteria

Complement deficiencies typically cause:

Recurrent infections

Live attenuated vaccines provide:

Strong lifelong immunity

Inactivated vaccines induce mainly:

Humoral immunity

Toxoid vaccines protect against:

Bacterial toxins

Conjugate vaccines link polysaccharides to :

Protein carriers

Which vaccine is live?

MMR (Measles, Mumps, Rubella)

Hyperacute transplant rejection is mediated by:

Performed antibodies

Acute graft rejection involves:

T-cells

Graft-versus-host disease occurs when:

Donor T cells attack host

Autografts come from:

Self

Calcineurin inhibitors block:

IL-2 production

Checkpoint inhibitors block:

PD-1/PD-L1 or CTLA-4

CAR-T therapy involves engineering:

T cells to target tumors

Tumor antigens are presented on:

MHC molecules

NK cells kill tumor cells by recognizing:

Low MHC I

Dendritic cell vaccines work by:

Presenting tumor antigens to T cells

Chronic transplant rejection is mediated by:

T cells and fibrosis

What cytokine stimulates NK cells?

IL-12

Monoclonal antibodies treat cancer by:

Targeting tumor antigens

PD-1 helps cancer cells by:

Inhibiting T cells

What molecule is commonly targeted in immunotherapy?

PD-L1

Tumor-infiltrating lymphocytes are:

T cells inside tumors

Cytokine-release syndrome in CAR-T therapy is due to:

Excess IL-6

CTLA-4 (cytotoxic T-Lymphocyte Antigen 4) inhibits:

T-cell activation

Hyperacute rejection occurs:

Minutes after transplantation

Cancer immune editing refers to:

Tumors mutating to escape immunity

what cells mediate ADCC (antibody-dependent cellular cytotoxicity)?

NK cells

Allografts come from:

Donors

Tumors escape immunity by:

Downregulating MHC I

Which vaccine requires booster shots?

Inactivated vaccines

Bispecific antibodies can:

bind two different antigens simultaneously

Which cytokine causes fever?

IL-1

The membrane attack complex is formed by which complement component?

C9

Which cell type releases histamine during allergic reactions?

Mast cells

Which cells kill tumor cells without prior sensitization?

NK cells

Tumor-specfic antigens are:

Uniquely expressed on tumor cells

Tumors evade immune detection by:

Secreting PD-L1

CD8 T cells recognized tumor cells through:

MHC I

Which is a checkpoint inhibitor?

Anti-PD-1 antibody

Tumor-associated antigens are:

normal proteins abnormally expressed

Which cells contribute to tumor immune suppression?

Tregs

CAR-T therapy involves engineering

T cells

Tumors evade surveillance by downregulating:

MHC I

Which cytokine enhances anti-tumor immunity?

IL-2

CTLA-4 functions to:

Suppress T cell activation

Tumor immunoediting phases include elimination, equilibrium, and:

Escape

ADCC occurs when:

NK cells recognize Fc of IgG

Tumor cells secreting VEGF cause:

Angiogenesis

Oncolytic viruses:

Kill tumor cells & stimulate immunity

Cold tumors are:

Low immune infiltration:

Tumor infiltrating lymphocytes are:

T cells in tumors

Tumors induce tolerance by:

Secreting IL-10 and TGF-β

Checkpoint blockade enhances:

T cell anti-tumor activity

Acute phase proteins are produced by the:

Liver