Matt Gethers/20.380 HIV Project/Meeting Notes/3.4.08 (Final Cut on Design Ideas)

3.4.08 (Final Cut on Design Ideas)

To Do

Make list of issues/questions to consider in implementing the engineered T-Cell idea.

Make list of issues/questions to consider in implementing the engineered RBC idea.

Questions

• What do we need to put into the person? What stage of progenitor cells? - (done!)
• Immunity issues with progenitor cells? - Rob
• How are RBCs removed/recycled from body? - Courtney
• Can HIV infect progenitor cells? - Matt
• How to couple CD4 expression, etc with RBC differentiation? - Rob
• Malaria - Courtney
• What's necessary and sufficient for HIV infection? - Matt
• What to do with HIV once in cell? Do we need it to do anything? - Rob
• How to prevent HIV from leaving RBC? - Jessie
• Death switch? - Jessie
• Exploding RBCs? - David
• Any natural conditions where RBCs die or explode? - David
  • A normal erythrocyte has a volume of about 90 fL=9.0 X 10^-17 L (a third of which is hemoglobin only freed up if we knock it out)
  • HIV is roughly a sphere of diameter 120nm --> volume of 9.05 X 10^-22 L
  • A normal RBC can theoretically hold a maximum of ~100,000 HIV virions if it has nothing else inside, including water
  • Damaged/misshapen RBCs are naturally destroyed in the spleen (i.e. anything but biconcave cells)
  • There is an entire class of disorders classified as "Hemolytic anemia" where RBCs are broken down prematurely/too much (http://en.wikipedia.org/wiki/Haemolytic_anemia)
  • Some are congenital
    • misshapen membrane
    • metabolic defects
    • sickle-cell anemia
    • thalassaemia
  • Some are acquired
    • autoimmune disorders
    • some drugs (ribavirin)
    • toxins
    • malaria and some other infections
  • Questions:
    • How many copies of HIV do we expect each RBC to hold? (question for modeling)
    • Can't find any papers on what happens when HIV virions aggregate in a small volume (could anything bad/unexpected happen? cross-linking?)
    • If we knock out hemoglobin, do we need to worry about too little osmotic pressure inside? Is Hb just replaced by ions from blood?

• Take out hemoglobin? Anything else to knock out? - Yi
• Pathologies of RBCs - esp. sickle cell anemia, thalassemia - Yi
• Ideal concentration of RBC progenitors? - Steph
• How to get into bone marrow? Easy injection method? - Steph
• Role of progenitors? - Steph

Make list of issues/questions to consider in implementing the superinfection idea.

Questions

• Does superinfection apply across strains?
• Fidelity of superinfection? How often does it fail?

- Matt

1. Divide work for presentation next week (3/12/09)
2. Modify calendar to reflect changes in schedule.

Minutes

Seven Ideas

Follow Up

Erythropoiesis

• Cell Lineage Map
  • Need to start with hematapoeic stem cell
    • knock out other lineages? (maybe we could leave them? would it be a problem?)