Host Defense and Vaccination

Flashcards from lecture notes.

Immune System

The primary function of this system is host defense.

Innate Immune System

These cells are largely myeloid cells, but also include NK cells.

Adaptive Immune System

These cells include T cells and B cells, which are adaptive lymphocytes.

Signal One (T cell activation)

This signal comes from TCR (T cell receptor) signaling through recognition of cognate peptide presented by dendritic cells.

Signal Two (T cell activation)

This signal is delivered by CD28, constitutively expressed on T cells, engaging with co-stimulatory molecules like CD80 or CD86 expressed by dendritic cells.

Pattern Recognition Receptors

Sensing molecules that strategically localize in different locations to recognize different types of ligands (PAMPs and DAMPs).

PAMPs

Pathogen-associated molecular patterns are molecules associated with pathogens that are recognized by the immune system.

DAMPs

Damage-associated molecular patterns are host-derived molecules released by damaged cells that trigger inflammation.

Natural Killer (NK) Cells

Lymphocytes in the innate immune system that can kill infected cells and produce inflammatory cytokines.

Complement System

A system with different components that can be triggered by classical, alternative, and lectin pathways, contributing to host control of infection.

Active Immunity

Induced by a host response to a microbe or microbial antigen.