Immunology and Pathobiology Study Guide

Who first noticed survivors of a plague became resistant (430 BC)?

Thucydides

Who developed the first vaccine using cowpox (1796)?

Edward Jenner

Who proposed germ theory, showing microbes cause disease?

Robert Koch

Who developed vaccines for cholera & rabies?

Louis Pasteur

Who showed antibodies neutralize toxins?

Behring & Kitasato

What are the 4 major pathogen types?

Viruses, bacteria, fungi, parasites

What is immunology?

The study of the immune system

What is immunity?

Protection against infection, toxins, or cancer

What is the immune system?

Cells, organs, and molecules defending the body

What is an antigen?

Any foreign molecule that triggers an immune response

What are antibodies (immunoglobulins)?

Y-shaped proteins that bind to antigens

What are cytokines?

Messenger proteins for immune cell communication

What are chemokines?

Proteins that direct immune cells to infection sites

What is inflammation?

Protective response causing redness, swelling, pain, heat

Key features of innate immunity?

Immediate, non-specific, no memory

Examples of innate immunity?

Skin, mucous, stomach acid, phagocytes, complement

Key features of adaptive immunity?

Slower, highly specific, has memory

What cells drive adaptive immunity?

B and T lymphocytes

What is active immunity?

Body makes its own antibodies/memory cells (infection or vaccine)

Is active immunity long-lasting or short-term?

Long-lasting (memory)

What is passive immunity?

Antibodies transferred from another source (mother’s milk, serum)

Is passive immunity long-lasting or short-term?

Short-term (no memory)

Function of macrophages?

Eat microbes and dead cells

Function of neutrophils?

First responders against bacteria/fungi

Function of eosinophils?

Kill parasites, involved in allergies

Function of basophils?

Release histamine during allergies

Function of monocytes?

Precursors to macrophages & dendritic cells

Function of NK cells?

Kill virus-infected and tumor cells

Function of B cells?

Produce antibodies (humoral immunity)

Function of CD4⁺ helper T cells?

Activate other immune cells via cytokines

Function of CD8⁺ cytotoxic T cells?

Kill infected and tumor cells

Function of regulatory T cells?

Suppress overactive immune responses

What are memory cells?

Long-lived lymphocytes for faster secondary responses

3 main antigen-presenting cells?

Dendritic cells, macrophages, B cells

What is clonal selection?

Only antigen-specific cells activate

What is clonal expansion?

Activated immune cells multiply

What is tolerance in immunity?

Prevents immune attack against self

What is immune memory?

Faster, stronger response upon re-exposure

What are primary lymphoid organs?

Bone marrow (B cells), thymus (T cells)

What are secondary lymphoid organs?

Lymph nodes, spleen, mucosal tissues

Role of lymph nodes?

Filter lymph, present antigens, activate lymphocytes

Role of spleen?

Filter blood, remove old RBCs, detect blood antigens

Role of mucosal/skin immune system?

Protect entry points (gut, lungs, skin) while tolerating harmless microbes

Key zones in lymph nodes?

B cells in follicles; T cells in paracortex

Key zones in spleen?

White pulp (lymphocytes), red pulp (RBC removal), marginal zone (B/macrophages)

Chemokine that attracts B cells?

CXCL13

Chemokine that attracts T cells?

CCR7 ligands

Difference in speed: innate vs adaptive immunity?

Innate = immediate; Adaptive = slower

Difference in specificity: innate vs adaptive?

Innate = non-specific; Adaptive = highly specific

Which immunity has memory?

Adaptive

Key players in innate immunity?

Phagocytes, NK cells, complement

Key players in adaptive immunity?

B and T cells

Example of innate immunity?

Skin barrier, macrophages

Example of adaptive immunity?

Vaccines, antibodies

Function of humoral immunity (B cells)?

Antibodies fight extracellular microbes and toxins

Function of cell-mediated immunity (T cells)?

CD4⁺ cytokines, CD8⁺ cytotoxic killing → fight intracellular microbes

Example of IgG antibodies?

Cross placenta → protect newborn

Example of IgA antibodies?

Found in breast milk, mucosal immunity

Autoimmunity definition & examples?

Self-attack; examples = Type 1 diabetes, rheumatoid arthritis

Allergies definition?

Immune overreaction to harmless antigen

Example of chronic inflammation?

Atherosclerosis (artery damage from immune attack)

Example of immune therapy?

Cytokine blockers, monoclonal antibodies

COVID-19 immune lesson?

Damage came from immune overreaction as much as virus

What maintains memory cells long-term?

Cytokines

Why is secondary immune response stronger?

Memory cells respond faster and in larger numbers