Cell-mediated immunity in genetically obese C57BL/6J ob/ob) mice

Area of Science:

• Immunology
• Obesity Research
• Cellular Biology

Background:

• Genetically obese (C57BL/6J ob/ob) mice exhibit altered immune organ weights and cellularity.
• Obesity is associated with changes in immune cell populations and function.

Purpose of the Study:

• To investigate the impact of genetic obesity on immune cell populations and functions in mice.
• To explore the relationship between obesity-induced metabolic changes and immune competence.

Main Methods:

• Comparative analysis of thymus and spleen from obese and lean mice.
• Assessment of mononuclear cells, lymphocyte populations (Thy 1.2-positive), and antibody-producing cells.
• Evaluation of natural killer (NK) cell activity and antibody-dependent cell-mediated cytotoxicity (ADCC).
• In vivo and in vitro immunization protocols to assess cytotoxic T cell responses.

Main Results:

• Obese mice had reduced thymus and spleen weights, fewer mononuclear cells, and lower Thy 1.2-positive lymphocytes.
• A significant decrease in splenic antibody-forming cells, especially IgG-producing cells, was observed in obese mice.
• Markedly increased NK cell activity and a slight increase in ADCC were noted in obese animals.
• In vivo cytotoxic T cell response was impaired in obese mice, while in vitro generation of T killer cells was normal.

Conclusions:

• Obesity in mice leads to significant alterations in immune organ cellularity and function.
• Impaired antibody production and in vivo cytotoxic responses suggest a compromised immune system in obesity.
• The data indicate a potentially deleterious microenvironment in obesity affecting immune cell function.
• Metabolic, nutritional, and endocrine factors associated with obesity likely contribute to altered immunocompetence.