Molecular mechanisms for TNF-mediated inhibition of B lymphocyte function

Project: Research project

Description

DESCRIPTION (provided by applicant): 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.
StatusFinished
Effective start/end date8/1/127/31/15

Funding

  • National Institutes of Health: $191,250.00
  • National Institutes of Health: $215,730.00

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B-Lymphocytes
Tumor Necrosis Factor-alpha
Immunoglobulin Isotypes
Genetic Recombination
Antibodies
Cytokines
B-Lymphocyte Subsets
Communicable Diseases
B-Lymphoid Precursor Cells
Vaccines
Influenza Vaccines
Immunoglobulins
Cultured Cells
Vaccination
Cell Culture Techniques
Biomarkers
Quality of Life
Outcome Assessment (Health Care)
Antigens
Antibody Formation

ASJC

  • Medicine(all)
  • Immunology and Microbiology(all)