Immune Structure
What is a vaccine?
*vaccination = action of getting a vaccine =/= immunization (the result of a vaccine)
Who developed the inactivated polio vaccine and how is it delivered?
Jonas Salk
- Shot, requires a large dose and skilled personnel
What does the "bio" in biomaterials mean?
Biocompatible (since biomaterials are required to not cause harm to the host body)
What are three animals serve as bioinspiration for tissue engineering?
- Lizards (tails)
- Newts (tails and limbs)
- Zebrafish (heart)
What innate immune cell is responsible for inflammatory reactions?
Basophils
This immune cell is stored in the lymph nodes for a long time and allows [?] cells to produce the same antibodies faster when invaded by the same pathogen.
What is a memory B cell?
Where are the two remaining samples of active variola virus stored?
CDC (Atlanta, Georgia, USA)
Vector Institute (Kosovo, Novosibirsk Oblast, RU)
What are the two types of biomaterials when classified by nature?
- Metal (Stainless steel, Co-Cr, Titanium, Nitinol, Mg)
- Ceramic (bioactive v. inert)
- Polymer (Dr. Ecker's lecture)
What is tissue engineering?
An interdisciplinary field that applies the principles of engineering and life sciences towards the development of biological subsitutes that restore, maintain, or improve tissue function or a whole organ
Why is titanium better than Co-Cr?
Lighter weight, has a stable oxidation layer, and compatible with imaging procedures (ex. MRI, CT)
List the four cellular pathogens.
Parasites (helminthes, tapeworm), Protozoa (plasmodia, malaria), Fungi (tinea, athlete's foot), Prokaryote (bacteria, leprosy)
*Bonus noncellular pathogens: Virus / Prion (misfolded protein)
What two men worked with cowpox to aid in the development of a vaccine?
Edward Jenner (blister fluid from cows) & Benjamin Jesty (blister fluid from people)
What are the four types of biomaterials when classified by activity?
- Bioinert
- Bioactive
- Biodegradable
- Smart
How was the Vacanti mouse created?
1. PGA/GLA cast made from plaster replica of an actual ear to make the scaffold
2. Scaffold seeded with chondrocytes and cultured (1 week)
3. Scaffold w/ cells is implanted subcutaneously on the back of the mouse
What are the two bioinert ceramics?
Alumina oxide and Zirconia
List the five passive defense barriers.
- Saliva (antibacterial enzymes, lysosomes)
- Tears (antibacterial enzymes)
- Skin (prevents entry, topmost layer is dead/no nuclei)
- Stomach acid (low pH kills harmful bacteria)
- "Good" gut bacteria (outcompetes the bad)
- Mucus linings (trap dirt/microbes)
Describe the four types of viral vaccines and give examples.
1. Live attenuated virus: weakened form of a virus, the strongest type (smallpox/cowpox)
2. Whole inactivated virus: killed form of a virus (polio shot, rabies, hep A)
3. Toxoid: inactivated toxins produced by a germ (diphtheria, tetanus, pertussis)
4. Subunit: uses portions of a virus (recombinant DNA), the weakest type (hep B, HPV)
What is Young's modulus and why is it important?
Stress / Strain; the steeper the slope the stiffer the material.
A stiff material (high YM) can cause stress shielding, which leads to bone loss.
What are the three kinds of mature cells used in tissue engineering?
- Autologous cells
- Allogenic cells
- Xenogeneic cells
Describe the differenced between viruses and antibiotics?
Target, mechanism, when, side effects?
Target: viruses/some bacteria | bacteria ONLY
Mechanism: stimulate body's immune response to killl pathogens | break down cell wall
When: before infection | during the time of disease/after infection
Side effects: mild, fewer effects | more invasive, can kill normal flora
What are the four types of T-cells (adaptive)?
- Cytotoxic T-cells (induce apoptosis)
- Helper T-cells (formulate attack strategies based on the pathogen type)
- Memory T-cells (equipped to attack again when seeing a pathogen again)
- Regulatory T-cells (control cytotoxic T-cells and suppress excess immune response)
Describe the viral life cycle.
Attachment, penetration, uncoating, biosynthesis, assembly, and release
Describe how bioactive ceramics work.
Osteoinduction (recruitment of immature cells and stimulation of cells to develop in to preosoteoblasts)
Osteoconduction (bone cells grow on a surface)
Osseointegration (stable implant anchorage, direct bone-implant contact)
Briefly explain the tissue engineering paradigm.
Harvest cells -> expand/culture cells -> seed cells on scaffold w/ bioactive molecules and co-culture -> construct w/ cells in scaffold cultured -> implant construct
List the different forms of ECM scaffolds.
Hydrated/Lyophilized sheet, lyophilized powder, hydrogel, ECM/polymer hybrid