In contrast, antibodies induced by the low-density conjugate had narrower reactivity and did not bind the clustered Tn immunized mice with 131I-iododeoxyuridine-labeled cells and whole-body measurement of retained radioactivity
antibody was followed in vivo with 131I-iododeoxyuridine-labeled cells and whole-body measurement of retained radioactivity. The in vivo killing of LR cells was proportional to the in vitro 2-mercaptoethanol resistant titer, independent of the complement system, and radioresistant. Although a large percentage of the leukemic cells was killed in passively immunized mice, the protective effect of the passive antiserum was dependent on the active immune response of the host.Induced by an Inactivated, Preservative-free Hepatitis A Vaccine (Healive) in the prevention of disease from the hepatitis A virus (HAV). Due to documented difficulties during decade-long follow-ups after receiving vaccines, statistical-modeling approaches have been applied to predict the duration of immune protection. METHODS: Based on five-year follow-up data from a randomized months vaccination schedule, a power-law model accounting for the kinetics of B-cell turnover, as well as a modified power-law model considering a memory-B-cell subpopulation, were fitted to predict the long-term immune responses induced by HAV vaccination (Healive or Havrix).
Anti-HAV levels of each individual and seroconversion rates up to 30 years after vaccination were predicted. RESULTS: A total of 375 participants who completed the two-dose vaccination were included in the analysis. Both models predicted that, over a life-long period, participants vaccinated with Healive would have close but slightly higher antibody titers than those of participants vaccinated with Havrix. Additionally, consistent with previous studies, more than 90% of participants were predicted to maintain seroconversion for at least 30 years. Moreover, the modified power-law model predicted that the antibody titers would reach a plateau level after nearly 15 years post-vaccination. CONCLUSIONS: Based on the results of our modeling, Healive may adequately induce long-term immune responses following a 0, 6 months vaccination schedule in children via induction of memory B cells to provide stable and durable immune protection.in protecting non-human primates against experimental rotavirus infection.
Pooled sera with rotavirus-specific IgG titers that were either high (1:10,000), intermediate (1:300), or negative (< 1:25) were infused i.v. into naive pigtailed macaques (ages 3-6 months). Rotavirus-specific IgG could be detected in the sera at 18 h in all animals infused with antibody-containing serum, and fecal IgG titers could be detected only in animals given high-titer pooled sera. When orally challenged with 10(6) fluorescent-forming units of a simian rotavirus strain, YK-1, at 18 h after serum transfer, control animals shed virus starting 1-3 days after challenge and continued to shed virus at high titers for 6-8 days, whereas passively immunized macaques did not shed virus or had delayed shedding at low titers for only a limited time. Check Details that passively transferred antibodies can suppress or delay viral infection in rotavirus-challenged pigtailed macaques has important implications for the design and testing of parenteral candidate rotavirus vaccines.Respiratory and Enteric Viruses Branch, National Center for Infectious Diseases, primary vaccination with recombinant hepatitis B vaccine at infancy.
(anti-HBs≥10 mIU/mL) in 90-99% of vaccinees. The levels of anti-HBs antibody decline after vaccination. The aim of this study was to evaluate the persistence of anti-HBs antibodies and immunologic memory in healthy adults at 20 years after primary vaccination with recombinant HB vaccine. Blood samples were collected from 300 adults at 20 years after primary HB vaccination and their sera were tested for anti-HBs antibody by ELISA technique. A single booster dose of HB vaccine was administered to a total of 138 subjects, whose anti-HBs antibody titer was <10 mIU/mL. The sera of subjects were re-tested for the anti-HBs antibody levels at 4 weeks after booster vaccination. At 20 years after primary vaccination 37.
0% of participants had protective levels of antibody with geometric mean titer (GMT) of 55.44±77.01 mIU/mL. After booster vaccination, 97.1% of vaccinees developed protective levels of antibody and the GMT rose from 2.35±6.