We propose to immunize 100 adult volunteer platelet donors at the Sidney Farber Cancer Institute with currently available vaccines directed against Haemophilus influenzae type b, Streptococcus pneumoniae and Neisseria meningitidis. Donors will be plasmapheresed repeatedly and plasma containing high concentrations of specific antibody will be pooled and fractionated by the Cohn method at the Massachusetts Biologic Laboratory to make a specific Bacterial Polysaccharide Immune Globulin (BPIG) directed against these bacterial pathogens. The BPIG preparation and a conventional immune serum globulin (ISG) (prepared by the Massachusetts Biologic Laboratory from the recovered plasma of normal blood donors) will be characterized for concentrations of specific antibody to each organism by radioactive antigen binding, quantitative precipitation, bactericidal activity, and opsonizing activity. The magnitude and duration of specific antibacterial antibody achieved in the serum with each preparation will be compared in small groups of approximately six children who are at high risk of developing infections with one or more of these organisms, including children with sickle cell disease, recurrent otitis media, congenital or surgical asplenia, agammaglobulinemia, acute leukemia and household contacts of patients with H. influenzae type b infections. This pharmacologic information will then be used to design dosage schedules for large scale efficacy trials of BPIG in the prophylaxis and therapy of infections caused by these bacteria. Ancillary studies will correlate the antibody responses of the immunized donors with their concentrations of IgG subclasses, immunoglobulin allotypes, subtypes of the 4th component of complement and HLA types (A,B,C, and DR).