Aging is associated with a decline in the ability of the individual to mount protective immune responses. Understanding the molecular mechanisms of the age-related impairment in immune functions will help to prevent infectious diseases and improve the biological quality of life in the elderly. Aging is characterized by increased plasma levels of pro-inflammatory cytokines such as TNF-alpha, and these can have deleterious effects as they are implicated in the pathogenesis of several disabling diseases of the elderly. We hypothesize that this pro-inflammatory status of the elderly, called inflammaging, impairs the capacity of the individual to make protective antibodies and to respond to vaccination. Specifically, our preliminary data indicate that the increased inflammatory response typical of old age is also contributed by B lymphocytes and this negatively impacts their function , including the ability to undergo class switch recombination (CSR) of immunoglobulin (Ig), critical for optimal effector function of antibodies specific for exogenous antigens. In this R21 application we will characterize novel molecular mechanisms leading to reduced B cell responses in the elderly which in the future should be able to be used as new targets for their improvement. We will evaluate whether B cells ex vivo isolated from elderly individuals make more TNF-alpha than those from younger ones, determine which B cell subset makes TNF-alpha, and how much compared to other cell types known to be primary sources of this cytokine. Particular questions addressed are whether the intrinsic defect of B cells from elderly individuals in Ig class switch is due to the initial ability of the B cell to make TNF-alpha. This will also be correlated with the in vivo anti-influenza vaccine response in these subjects. We will characterize the mechanisms by which TNF-alpha impairs the ability of B cells to undergo CSR by pre-incubating B cell cultures with TNF-alpha and evaluate if the in vitro Ig class switch can be "rescued" with an anti-TNF-alpha antibody added to cultured B cells. Outcome measures will be molecular biomarkers we have previously discovered to predict optimal B lymphocyte responses. The experiments proposed in this R21 application offer an innovative approach to characterize further mechanisms which decrease B cell responses in elderly individuals. These studies should have immediate impact on crucial development of effective vaccines to protect elderly individuals from diseases typical of old age.

Public Health Relevance

The studies proposed here investigate novel molecular mechanisms for decreased human B lymphocyte and antibody responses, important for optimal response to vaccines, infectious diseases, and cancer. These mechanisms may also help to explain the overall increase seen in inflammation in the elderly, which contributes to disorders of the immune system, heart, and brain.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AI096446-02
Application #
8519286
Study Section
Aging Systems and Geriatrics Study Section (ASG)
Program Officer
Prabhudas, Mercy R
Project Start
2012-08-01
Project End
2014-07-31
Budget Start
2013-08-01
Budget End
2014-07-31
Support Year
2
Fiscal Year
2013
Total Cost
$215,730
Indirect Cost
$74,730
Name
University of Miami School of Medicine
Department
Microbiology/Immun/Virology
Type
Schools of Medicine
DUNS #
052780918
City
Coral Gables
State
FL
Country
United States
Zip Code
33146
Frasca, Daniela; Diaz, Alain; Romero, Maria et al. (2014) High TNF-? levels in resting B cells negatively correlate with their response. Exp Gerontol 54:116-22
Frasca, Daniela; Blomberg, Bonnie B (2014) B cell function and influenza vaccine responses in healthy aging and disease. Curr Opin Immunol 29:112-8
Scholz, Jean L; Diaz, Alain; Riley, Richard L et al. (2013) A comparative review of aging and B cell function in mice and humans. Curr Opin Immunol 25:504-10
Frasca, Daniela; Diaz, Alain; Romero, Maria et al. (2013) Effects of age on H1N1-specific serum IgG1 and IgG3 levels evaluated during the 2011-2012 influenza vaccine season. Immun Ageing 10:14
Andrisani, G; Frasca, D; Romero, M et al. (2013) Immune response to influenza A/H1N1 vaccine in inflammatory bowel disease patients treated with anti TNF-? agents: effects of combined therapy with immunosuppressants. J Crohns Colitis 7:301-7