Age-related changes in B cell metabolism

Antibody responses to vaccinations or infections decline upon aging. In this study we tested if metabolic changes in B cells may contribute to attenuation of responses to influenza vaccination in aged humans. Our data show that aging affects mitochondrial functions in B cells leading to increases in mitochondrial reactive oxygen species (MROS) and mitochondrial mass (MM) in some aged B cell subsets and decreases in expression levels of Sirtuin 1 (SIRT1), Forkhead box protein (FOX)O1 and carnitine palmitoyltransferase 1 (CPT-1). Seahorse analyses showed minor defects in glycolysis in the aged B cells after activation but a strong reduction in oxidative phosphorylation. The analyses of the transcriptome revealed further pronounced defects in one-carbon metabolism, a pathway that is essential for amino acid and nucleotide metabolism. Overall our data support the notion that the declining ability of aged B cells to increase their metabolism following activation contributes to the weakened antibody responses of the elderly.

Immunity and longevity

The role of immune system is to protect the organism from the not built-in program-like alterations inside and against the agents penetrating from outside (bacteria, viruses, and protozoa). These functions were developed and formed during the evolution. Considering these functions, the immune system promotes the lengthening of lifespan and helps longevity. However, some immune functions have been conveyed by men to medical tools (e.g., pharmaceuticals, antibiotics, and prevention), especially in our modern age, which help the struggle against microbes, but evolutionarily weaken the immune system. Aging is a gradual slow attrition by autoimmunity, directed by the thymus and regulated by the central nervous system and pineal gland. Considering this, thymus could be a pacemaker of aging. The remodeling of the immune system, which can be observed in elderly people and centenarians, is probably not a cause of aging, but a consequence of it, which helps to suit immunity to the requirements. Oxidative stress also helps the attrition of the immune cells and antioxidants help to prolong lifespan. There are gender differences in the aging of the immune system as well as in the longevity. There is an advantage for women in both cases. This can be explained by hormonal differences (estrogens positively influences both processes); however, social factors are also not excluded. The endocrine disruptor chemicals act similar to estrogens, like stimulating or suppressing immunity and provoking autoimmunity; however, their role in longevity is controversial. There are some drugs (rapamycin, metformin, and selegiline) and antioxidants (as vitamins C and E) that prolong lifespan and also improve immunity. It is difficult to declare that longevity is exclusively dependent on the state of the immune system; however, there is a parallelism between the state of immune system and lifespan. It seems likely that there is not a real decline of immunity during aging, but there is a remodeling of the system according to the claims of senescence. This is manifested in the remaining (sometimes stronger) function of memory cells in contrast to the production and number of the new antigen-reactive naive T-cells.

Update on the use of immunoglobulin in human disease: A review of evidence

Human immunoglobulin preparations for intravenous or subcutaneous administration are the cornerstone of treatment in patients with primary immunodeficiency diseases affecting the humoral immune system. Intravenous preparations have a number of important uses in the treatment of other diseases in humans as well, some for which acceptable treatment alternatives do not exist. We provide an update of the evidence-based guideline on immunoglobulin therapy, last published in 2006. Given the potential risks and inherent scarcity of human immunoglobulin, careful consideration of its indications and administration is warranted.

Utilizing the age-related widening of the gingival crevice as a potential non-invasive vaccination route: Prospects for elderly vaccination

Gingival crevice (GC) increases with age allowing periodontopathic bacteria and its products to enter. We hypothesize that by mimicking this event we can utilize the GC as a potential vaccination route. Here, we used 20 wk-old (young) and 77 wk-old (old) Sprague-Dawley rats. Initially, we elucidated the difference between oral-administration and oral-supplementation in both young and old rats and, subsequently, we determined the optimal component concentration for xanthan gel-encapsulation. Next, through molecular docking, we simulated xanthan gel-encapsulation of a representative antigen (for this study we used influenza H5N1 hemagglutinin) in order to verify that target epitopes were not blocked. Lastly, we compared the antibody titer among gingival-vaccinated rats (old and young) and, likewise, we evaluated the antibody titer produced via the gingival route as compared to other vaccination routes (intradermal, oral, sublingual). Rat blood serum was collected for further downstream analyses. Throughout the study, we were able to establish the following conditions: higher target components enter old rats via oral-supplementation; 100 μg mL(-1) is the optimal component concentration for xanthan gel-encapsulation; and xanthan gel-encapsulation leaves antibody epitopes exposed. More importantly, we observed that gingival-vaccinated old rats have higher antibody titer as compared to young rats and, likewise, we found that antibody titer elicited via gingival vaccination is comparable to other mucosal vaccination routes. Thus, we propose that the GC has the potential to serve as a non-invasive vaccination route.

Phosphatase Wip1 controls antigen-independent B-cell development in a p53-dependent manner

Wild-type p53-induced phosphatase 1 (Wip1), a phosphatase previously considered as an oncogene, has been implicated in the regulation of thymus homeostasis and neutrophil maturation. However, the role of Wip1 in B-cell development is unknown. We show that Wip1-deficient mice exhibit a significant reduction of B-cell numbers in the bone marrow, peripheral blood, and spleen. A reciprocal transplantation approach revealed a cell-intrinsic defect in early B-cell precursors caused by Wip1 deficiency. Further experiments revealed that Wip1 deficiency led to a sustained activation of p53 in B cells, which led to increased level of apoptosis in the pre-B-cell compartment. Notably, the impairment of B-cell development in Wip1-deficient mice was completely rescued by genetic ablation of p53, but not p21. Therefore, loss of Wip1 phosphatase induces a p53-dependent, but p21-independent, mechanism that impairs B-cell development by enhancing apoptosis in early B-cell precursors. Moreover, Wip1 deficiency exacerbated a decline in B-cell development caused by aging as evidenced in mice with aging and mouse models with serial competitive bone marrow transplantation, respectively. Our present data indicate that Wip1 plays a critical role in maintaining antigen-independent B-cell development in the bone marrow and preventing an aging-related decline in B-cell development.

Preventing or reversing immunosenescence: can exercise be an immunotherapy?

There is now a strong body of evidence demonstrating that aging is accompanied by severe alterations in the immune system, a process known as immunosenescence. Among these changes are alterations in T-cell subpopulation size, cytokine secretion pattern, cell replicative capacity and antibody production, all of which culminate in a proinflammatory state called 'inflammaging' and a diminished capacity to respond to new antigens. These alterations are closely related to the increased mortality and morbidity rates observed in this population. However, the role of exercise on the prevention or treatment of immunosenescence is virtually unknown. Data gathered from the literature regarding the effects of physical activity on immune system aging are still limited and conflicting, with existing reports either advocating benefits or asserting a lack of evidence. Exercise as part of a healthy lifestyle has already been shown to provide long-term benefits with regard to cardiovascular, cognitive, psychosocial and other aspects of the elderly. If positive effects are also observed for immunosenescence, exercise could be a highly cost-effective measure to improve human quality of life compared with other strategies currently being pursued.

Immunosenescence and novel vaccination strategies for the elderly

Vaccination remains the most effective prophylactic intervention for infectious disease in the healthcare professional's toolkit. However, the efficacy and effectiveness of vaccines decrease with age. This becomes most apparent after an individual reaches 65-70 years old, and results from complex changes in the immune system that occur during aging. As such, new vaccine formulations and strategies that can accommodate age-related changes in immunity are required to protect this expanding population. Here, we summarize the consequences of immunosenescence on vaccination and how novel vaccination strategies can be designed to accommodate the aging immune system. We conclude that current vaccination protocols are not sufficient to protect our aging population and, in some cases, are an inefficient use of healthcare resources. However, researchers and clinicians are developing novel vaccination strategies that include modifying who and when we vaccinate and capitalize on existing vaccines, in addition to formulating new vaccines specifically tailored to the elderly in order to remedy this deficiency.

Early alterations of B cells in patients with septic shock

Introduction

It has recently been proposed that B lymphocytes are involved in sepsis pathogenesis. The goal of this study is to investigate potential abnormalities in a subset distribution and activation of circulating B lymphocytes in patients with septic shock.

Methods

This observational prospective study was conducted in a medical-surgical ICU. All patients with septic shock were eligible for inclusion. B-cell phenotypes (CD19+CD69+, CD19+CD23+, CD19+CD5+, CD19+CD80, CD19+CD86+, CD19+CD40 and CD19+CD95+) were assessed by quantitative flow cytometry upon admission to the ICU and 3, 7, 14 and 28 d later.

Results

Fifty-two patients were included. Thirty-six healthy volunteers matched for age and sex were used as controls. The patients had lymphopenia that was maintained during 28 d of follow-up. In patients with septic shock who died, the percentage of CD19+CD23+ was lower during the 7 d of follow-up than it was in survival patients. Moreover, the percentage of CD80+ and CD95+ expression on B cells was higher in patients who died than in survivors. Receiver operating characteristic curve analysis showed that a CD19+CD23+ value of 64.6% at ICU admission enabled discrimination between survivors and nonsurvivors with a sensitivity of 90.9% and a specificity of 80.0% (P = 0.0001).

Conclusions

Patients with septic shock who survive and those who don't have different patterns of abnormalities in circulating B lymphocytes. At ICU admission, a low percentage of CD23+ and a high of CD80+ and CD95+ on B cells were associated with increased mortality of patients with septic shock. Moreover, a drop in circulating B cells persisted during 28 d of ICU follow-up.