The role of CD8+, CD57+ cells in human cytomegalovirus and other viral infections.
Source
Department of Medicine, University of Wales College of Medicine, Heath Park, Cardiff, UK.
Abstract
Peripheral blood lymphocytes expressing CD8 and CD57 determinants are a small (1-15%) subset in healthy humans. CD8+, CD57+ peripheral blood lymphocytes may be divided by the level of CD8 expression, into CD8+high (CD57+) T-cells and CD8+low (CD57+) natural killer (NK) cells. CD8+high (CD57+)
T-cell numbers are increased in human cytomegalovirus
(HCMV)-seropositive subjects, and there is substantial evidence that
HCMV is integral in the development of this subset in health and
disease. Furthermore, the CD8+high (CD57+)
subset is clonally derived, expressing a limited range of T-cell
receptors, and are therefore likely to have restricted antigen
specificity. Functionally, CD8+low(CD57+) cells exhibit NK activity, while CD8+high(CD57+)
T-cells from healthy subjects mediate contact-dependent suppression in
several in vitro systems including: (i) pokeweed mitogen-induced
proliferation and immunoglobulin synthesis, and (ii) generation of
antiviral MHC-restricted cytotoxic T-lymphocytes. This is distinct from
the nonspecific, soluble factor-mediated suppression exhibited from a
phenotypically similar subset in human immunodeficiency virus (HIV) and
bone marrow transplant recipients. This suggests an important
immunoregulatory, suppressive role for CD8+high(CD57+)
T-cells that may be potentiated by HCMV and altered in diseases
associated with higher numbers of this subset including HIV, allograft
recipients and rheumatoid arthritis.
