Lecture 1: Immune System Intro Flashcards
Types of microbes
- Viruses
- Fungi
- Bacteria
- Parasites
Features of viruses
- Obligate IC parasites (req. host cell)
- Enveloped and non-enveloped
- Inserts viral nucleic acid to produce viral proteins
Features of fungi
-Eukaryotic, nucleated
Features of bacteria
- Single cell prokaryotes
- Gram positive or Gram negative
What type of bacteria have LPS (endotoxin) on their cell walls?
Gram negative bacteria
Features of parasites
- Req. hosts
- Protozoa = single cell eukaryotes
- Helminths aka worms = multicellular
Which CD marker is on all leukocytes?
CD45
Which CD marker is on all T lymphocytes?
CD3
What CD markers are on helper T cells?
CD45, CD3, CD4
What markers are on Tregs?
CD45, CD3, CD4, CD25, FoxP3 (Th subset)
What CD markers are on cytotoxic T cells?
CD45, CD3, CD8
What markers are on B cells?
CD45, CD19 or CD20, MHC II Fc receptors
What CD markers are on NK cells?
CD45, CD16
Purpose of the immune system
Protect the host from infection and danger
Requirements for an effective immune response
- Rapid
- Specific yet diverse
- Multiple effector functions
- Tolerance
- Memory
Features of innate immune system
- Rapid response
- Generalized
- No memory
- Germline receptors
- Always present in healthy individuals
Cellular + humoral innate immune mediators
Macrophages, neutrophils, DCs, NK cells, complement
Features of adaptive immune system
- Slower response (expansion + differentiation)
- Specific
- Acquired memory
- Somatic recombination receptors
- Potential for autoimmunity
Subtypes of adaptive immunity
- Humoral (B cells)
- Cellular (T cells)
Types of T cells
- T helper
- T cytotoxic
- T regulatory
Th cell functions
- IFN-γ secretion to activate mφ
- Activate B cells
- Trigger inflammation
Tc cell functions
- Kill infected cells
Treg cell functions
- Immune suppression
Components of cutaneous immune system
- Keratinocyte barrier
- Epidermal Langerhans cell (DC)
- Intraepithelial CD8+ T lymphocytes
Antigen Presenting Cells
- Dendritic cells
- Macrophages
- Epidermal Langerhans cells
Structural features of lymph nodes
- Follicles: B cell zone
- Paracortex: T cell zone
- Germinal center: proliferating B cells
Clonal selection
- APC presents Ag recognized by B/T lymphocyte
- Clonal activation and proliferation
How is a lymphocyte clone defined?
Clones are defined by their Ag receptor; each clone recognizes the same specific Ag. Specificity is given by the AA seq. of the receptor
