Regulatory effects mediated by OKT8+ subsets on B cell response in the elderly

Area of Science:

• Immunology
• Gerontology

Background:

• T cell-mediated B cell responsiveness is crucial for adaptive immunity.
• Age-related immune decline (immunosenescence) can impair T cell function and antibody production.

Purpose of the Study:

• To investigate the impact of aging on T cell-dependent B cell responsiveness.
• To identify specific T cell subsets and mechanisms involved in age-related changes in B cell function.

Main Methods:

• Utilized a Pokeweed mitogen (PWM)-driven differentiation system with peripheral blood mononuclear cells (PBMC) from 50 aged donors.
• Assessed plaque-forming cell (PFC) generation in response to T cell subset manipulation (OKT4+, OKT8+, OKT8+M1+, OKT8+M1-).
• Investigated the role of soluble suppressive factors and the effect of indomethacin.

Main Results:

• Aged donors exhibited significantly lower PFC generation compared to young donors.
• OKT4+ T cell addition partially restored B cell response in aged donors, but not to levels seen in young donors.
• Both OKT8+M1+ and OKT8+M1- subsets suppressed B cell response in aged donors, whereas only OKT8+M1+ cells suppressed in young donors.
• Soluble suppressive factors were identified as mediators of OKT8+M1--mediated suppression in aged individuals.

Conclusions:

• Aging is associated with altered T cell-B cell interactions, leading to impaired B cell responsiveness.
• Specific T cell subsets, particularly OKT8+M1- cells, exert suppressive effects on B cell function in the elderly through soluble factors.
• These findings highlight age-related changes in immune regulation impacting humoral immunity.