immune system study help

Which cell type rapidly ingests and destroys bacteria?

Neutrophils

What are the key features of neutrophils?

First responders; form pus; short life span

Which cell type performs phagocytosis and activates T cells?

Macrophages

Key features of macrophages?

Long-living; cytokine release; antigen-presenting

Which cells are professional antigen-presenting cells bridging innate & adaptive immunity?

Dendritic Cells

Main function of dendritic cells?

Bridge between innate & adaptive immunity

Which cells kill virus-infected and cancer cells without prior exposure?

Natural Killer (NK) Cells

Key feature of NK cells?

No MHC requirement; innate response

Which cells release histamine in the blood?

Basophils

Key feature of basophils?

Circulate in blood; involved in allergy responses

Which cells release histamine and mediate inflammation in tissues?

Mast Cells

Key feature of mast cells?

Found in tissues; key for anaphylaxis

Which cells attack parasites and play a role in allergies?

Eosinophils

Key feature of eosinophils?

Release enzymes/toxins

Which cells produce antibodies?

B Cells

Key feature of B cells?

Differentiate into plasma & memory B cells

Which T cells coordinate immune responses and activate other immune cells?

Helper T Cells (CD4+)

Key features of Helper T cells?

Activate B cells, T cells, macrophages

Which T cells kill infected or cancerous cells?

Cytotoxic T Cells (CD8+)

Key feature of cytotoxic T cells?

Target intracellular pathogens

Which T cells prevent overactivation of the immune system?

Regulatory T Cells

Key feature of regulatory T cells?

Maintain immune tolerance

Which T cells provide long-term immunity and respond quickly on re-exposure?

Memory T Cells

Key feature of memory T cells?

Quick response upon re-exposure to antigen

What is the main role of IgG?

Most abundant antibody; primary in secondary immune response; neutralizes toxins, viruses, bacteria; crosses placenta

Location of IgG?

Blood, tissues; crosses placenta

Think mnemonic for IgG?

G = Goes everywhere; Gives baby immunity

What is the main role of IgM?

First antibody produced during infection; excellent at agglutination; activates complement strongly

Location of IgM?

Bloodstream

Mnemonic for IgM?

M = Massive & immediate

What is the main role of IgA?

Protects mucosal surfaces; blocks pathogen attachment; provides passive immunity to infants

Location of IgA?

Secretions: saliva, tears, mucus, breast milk, GI tract

Mnemonic for IgA?

A = Areas exposed to Air (mucosa)

What is the main role of IgE?

Triggers histamine release during allergic reactions; defense against parasites; mediates type I hypersensitivity

Location of IgE?

Bound to mast cells and basophils

Mnemonic for IgE?

E = Environment allergies

What is the main role of IgD?

Acts as a B-cell receptor; helps activate B-cells during initial antigen exposure

Location of IgD?

Surface of B-lymphocytes

Mnemonic for IgD?

D = Development of B-cells

Neutrophils

Rapidly ingest and destroy bacteria; first responders; form pus; short life span

Macrophages

Phagocytosis; activate T cells; long-living; cytokine release; antigen-presenting

Dendritic Cells

Professional antigen-presenting cells; bridge between innate & adaptive immunity

Natural Killer (NK) Cells

Kill virus-infected and cancer cells; no prior exposure needed; no MHC requirement

Basophils

Release histamine; circulate in blood; involved in allergy responses

Mast Cells

Inflammation; histamine release; found in tissues; key for anaphylaxis

Eosinophils

Attack parasites; allergy role; release enzymes/toxins

B Cells

Produce antibodies; differentiate into plasma & memory B cells

Helper T Cells (CD4+)

Coordinate immune responses; activate B cells, T cells, macrophages

Cytotoxic T Cells (CD8+)

Kill infected/cancerous cells; target intracellular pathogens

Regulatory T Cells

Prevent overactivation; maintain immune tolerance

Memory T Cells

Long-term immunity; quick response on re-exposure

IgG

Most abundant antibody (75–80%); primary in secondary immune response; neutralizes toxins, viruses, bacteria; crosses placenta; provides passive immunity to newborns

IgM

First antibody produced during infection; excellent at agglutination; activates complement strongly; indicates recent infection

IgA

Protects mucosal surfaces; blocks pathogen attachment; provides passive immunity to infants; found in secretions like saliva, tears, mucus, breast milk

IgE

Triggers histamine release in allergies; defense against parasites; type I hypersensitivity; bound to mast cells and basophils

IgD

Acts as B-cell receptor; activates B-cells during initial antigen exposure; surface of B-lymphocytes; very low concentration in circulation