Signed informed consent will be obtained by an authorized investigator. The nature of the study as well as the risks and benefits of the donation process will be explained to each participant. Donors will be compensated for each blood donation or for unsuccessful attempts at venipuncture. Samples will be used solely for in vitro research. To ensure confidentiality, blood will be assigned a unique code; investigators listed on this protocol will serve as the custodians of the codes that link the samples to the donors' identities.