Fighting against a protean enemy: immunosenescence, vaccines, and healthy aging

Abstract The progressive increase of the aged population worldwide mandates new strategies to ensure sustained health and well-being with age. The development of better and/or new vaccines against pathogens that affect older adults is one pivotal intervention in approaching this goal. However, the functional decline of various physiological systems, including the immune system, requires novel approaches to counteract immunosenescence. Although important progress has been made in understanding the mechanisms underlying the age-related decline of the immune response to infections and vaccinations, knowledge gaps remain, both in the areas of basic and translational research. In particular, it will be important to better understand how environmental factors, such as diet, physical activity, co-morbidities, and pharmacological treatments, delay or contribute to the decline of the capability of the aging immune system to appropriately respond to infectious diseases and vaccination. Recent findings suggest that successful approaches specifically targeted to the older population can be developed, such as the high-dose and adjuvanted vaccines against seasonal influenza, the adjuvanted subunit vaccine against herpes zoster, as well as experimental interventions with immune-potentiators or immunostimulants. Learning from these first successes may pave the way to developing novel and improved vaccines for the older adults and immunocompromised. With an integrated, holistic vaccination strategy, society will offer the opportunity for an improved quality of life to the segment of the population that is going to increase most significantly in numbers and proportion over future decades

In vivo expansion of T reg cells with IL-2-mAb complexes: induction of resistance to EAE and long-term acceptance of islet allografts without immunosuppression.

Via a transcription factor, Foxp3, immunoregulatory CD4(+)CD25(+) T cells (T reg cells) play an important role in suppressing the function of other T cells. Adoptively transferring high numbers of T reg cells can reduce the intensity of the immune response, thereby providing an attractive prospect for inducing tolerance. Extending our previous findings, we describe an in vivo approach for inducing rapid expansion of T reg cells by injecting mice with interleukin (IL)-2 mixed with a particular IL-2 monoclonal antibody (mAb). Injection of these IL-2-IL-2 mAb complexes for a short period of 3 d induces a marked (>10-fold) increase in T reg cell numbers in many organs, including the liver and gut as well as the spleen and lymph nodes, and a modest increase in the thymus. The expanded T reg cells survive for 1-2 wk and are highly activated and display superior suppressive function. Pretreating with the IL-2-IL-2 mAb complexes renders the mice resistant to induction of experimental autoimmune encephalomyelitis; combined with rapamycin, the complexes can also be used to treat ongoing disease. In addition, pretreating mice with the complexes induces tolerance to fully major histocompatibility complex-incompatible pancreatic islets in the absence of immunosuppression. Tolerance is robust and the majority of grafts are accepted indefinitely. The approach described for T reg cell expansion has clinical potential for treating autoimmune disease and promoting organ transplantation

Cost-effectiveness analysis of infant pneumococcal vaccination with PHiD-CV in Korea

Background: Streptococcus pneumoniae and non-typeable Haemophilus influenzae (NTHi) can cause invasive pneumococcal diseases (IPD), pneumonia, and acute otitis media (AOM). Both the 10-valent pneumococcal NTHi protein D conjugate vaccine (PHiD-CV) and the 13-valent pneumococcal conjugate vaccine (PCV-13) are included in the National Immunization Program for infants in Korea. This study aimed to evaluate the cost-effectiveness of the 3+1 schedule of PHiD-CV versus that of PCV-13 for National Immunization Program in Korea. Methods: A published Markov model was adapted to evaluate the cost-effectiveness of vaccinating the 2012 birth cohort with PHiD-CV vs. PCV-13 from the Korean government perspective over 10 y. Best available published data were used for epidemiology, vaccine efficacy and disutilities. Data on incidence and direct medical costs were taken from the national insurance claims database. Sensitivity analyses were conducted to explore the robustness of the results. Results: PHiD-CV was projected to prevent an additional 195,262 cases of pneumococcal diseases and NTHi-related diseases vs. PCV-13, with a substantially greater reduction in NTHi-related AOM and a comparable reduction in IPD and community-acquired pneumonia. Parity-priced PHiD-CV generated a health gain of about 844 quality-adjusted life years and a total cost-saving of approximately 4 million United States Dollars (USD) over 10 y. 93% of probabilistic simulations found PHiD-CV 3+1 to be the dominant vaccine option. Conclusion: Compared to PCV-13, PHiD-CV was projected to provide similar prevention against IPD and community-acquired pneumonia but would prevent more cases of AOM. Parity-priced PHiD-CV was anticipated to generate substantial cost-savings and health benefits vs. PCV-13 in Korea