Compromised levels of CD6 and reduced T cell activation in the aged immune system

Abstract

The CD6 molecule, a cell surface marker, is involved in immunological synapse formation between T cell and antigen-presenting cell and T lymphocyte activation for adequate immune response. Geriatric individuals fail to mount a satisfactory immunological response against pathogens thus, insights into the functionality of CD6 may provide information for competence building in elderly immune cells. However, limited information is available regarding the status of CD6 in geriatric individuals. In this study, various isoforms of CD6 were analysed in aged mononuclear cells (MNCs) and compared with young individuals. In geriatric individuals, protein and mRNA expressions of CD6 molecule/isoforms were found to be decreased compared to their young counterparts. Furthermore, geriatric MNCs failed to show any change in CD6 levels and its isoforms upon polyclonal activation compared to young MNCs, marked by reduced Ca⁺⁺ release and IL-2 expression. We suggest an overall decrease in CD6 levels in geriatric MNCs and T cells with suboptimal T cell activation in aged individuals.

Keywords:

• Immunosenescence
• aging
• CD6
• CD6Δ3
• T cell activation

Acknowledgements

The authors thank all the human subjects who volunteered their participation in this study. We acknowledge Central Facility, Department of Biotechnology, MNNIT Allahabad for qPCR and flow cytometry facility. We are grateful to the Centre for Interdisciplinary Research, MNNIT Allahabad, for the fluorimeter facility. The present work was carried out as a part of the PhD work of Mr Amit Kumar Kureel; hence, MHRD and CSIR-UGC (GoI) are acknowledged for financial assistance to Mr Kureel in the form of fellowship.

Disclosure statement

The authors declare no conflict of interest.

Data availability statement

The authors confirm that the data supporting findings of the present study are available within the article and its supplementary materials. Raw data supporting the results are available from the CONTACT corresponding author [[email protected]] on request.

Additional information

Funding

This work was partially supported by TEQIP-II, MNNIT Allahabad, India [Ref No. MNNIT/146/R&C/13-14].