- Meets eligibility criteria for and agrees to enroll in "MT1999-06: Vaccination with Tetanus Toxoid and Keyhole Limpet Hemocyanin (KLH) to Assess Antigen-Specific Immune Responses" (IRB # 9904M01581, CPRC #2002LS032). Patients who have had tetanus toxoid within the last 7 years will not receive the tetanus vaccine component. For patients who do not know the year of their last tetanus vaccine, tetanus toxoid will be given per protocol. Subjects allergic to seafood will not be co-enrolled into MT1996-06.