1. Intraperitoneal injections of killed and living broth cultures of a virulent pneumococcus produce in guinea pigs a high degree of active immunity and a serum with strong protective power. 2. Despite the protective power of such serum no agglutinins for the homologous organism and no precipitins for soluble derivatives were demonstrable. 3. Guinea pig immunity to pneumococcus infection produc...

Background. Some screening and treatment programs implemented to control Chlamydia trachomatis genital infections and their complications have shown initial reductions in infection prevalence, followed by increases to preprogram levels or higher. One hypothesis is that treatment shortens duration of infection, attenuates development of protective immunity, and thereby, increases risk of reinfec...

Dengue is an expanding public health problem, and an effective vaccine remains elusive. This review discusses how the significant influence of sequential infection with different dengue virus serotypes on the severity of disease can be viewed in terms of beneficial and detrimental effects of heterologous immunity. A more complete understanding of these effects is likely to be critical for predi...

The influence in immunization with cholera toxin of the route and antigen dose on intestinal antibody formation and protective immunity against experimental cholera was studied in mice. Administration by either the intravenous or oral route induced effective priming as well as boosting of mucosal immunity, with the effects on intestinal immunoglobulin A antitoxin synthesis and protective antito...

Duration of vaccine-induced immunity plays a key role in the epidemiology and in the pattern of transmission of a vaccine-preventable disease. In the case of whooping cough, its re-emergence has been attributed, at least partly, to the waning of immunity conferred by current pertussis vaccines. We have recently developed a highly attenuated live vaccine, named BPZE1, which has been shown to be ...

Respiratory syncytial virus (RSV) is one of the leading causes of childhood hospitalization and a major health burden worldwide. Unfortunately, because of an inefficient immunological memory, RSV infection provides limited immune protection against reinfection. Furthermore, RSV can induce an inadequate Th2-type immune response that causes severe respiratory tract inflammation and obstruction. I...

Administration of anti-CD25 mAb before an aggressive murine breast tumor inoculation provoked effective antitumor immunity. Compared with CD4(+) T cells purified from anti-CD25 mAb-pretreated mice that did not reject tumor, CD4(+) T cells purified from anti-CD25 mAb-pretreated mice that rejected tumor stimulated by dendritic cells (DCs) produced more IFN-gamma and IL-2, and less IL-17 in vitro,...

Regulatory T cells (Tregs) down-regulate immunity and are associated with chronic viral infections, suggesting that their inhibition might be used to treat life-threatening diseases. Using the FrCasE mouse retroviral model, we have recently shown that short mAb-based immunotherapies can induce life-long protective immunity. This finding has a potentially important therapeutical impact because m...

Despite significant advances in our understanding of the biology and antigenic structure of Chlamydia trachomatis, and the epidemiology and clinical spectrum of chlamydial disease, the magnitude of morbidity from human chlamydial infections remains an important public health concern. Control of chlamydial disease will likely depend on a multidisciplinary approach, including the development of i...