Oligoclonality in the human CD8+ T cell repertoire in normal subjects and monozygotic twins: implications for studies of infectious and autoimmune diseases.
BACKGROUND
We have previously demonstrated CD8+ T cell clonal dominance using a PCR assay for the CDR3 length of T cell receptors belonging to a limited number of TCRBV segments/families. In this study, we have modified this approach in order to analyze more comprehensively the frequency of oligoclonality in the CD8+ T cell subset in 25 known TCRBV segments/families. In order to assess the relative roles of genes and environment in the shaping of a clonally restricted CD8+ T cell repertoire, we have analyzed clonal dominance in the CD8+ T cell population of monozygotic twins, related siblings, and adoptees.


METHODS
Oligoclonality was assessed in the CD8+ T cell subsets using a multiplex PCR approach to assay for CDR3 length variation across 25 different TCRBV segments/families. Specific criteria for oligoclonality were established, and confirmed by direct sequence analysis of the PCR products. This assay was used to investigate the CD8+ T cell repertoire of 56 normal subjects, as well as six sets of monozygotic (MZ) twins.


RESULTS
Seventy-two percent of normal subjects (n = 56) had evidence of oligoclonality in the CD8+ T cell subset, using well-defined criteria. Although MZ twins frequently displayed CD8+ T cell clonal dominance, the overall pattern of oligoclonality was very diverse within each twin pair. However, we occasionally observed dominant CD8+ T cell clones that were highly similar in sequence in both members of some twin pairs. Not a single example of such similarity was observed in normal controls or siblings.


CONCLUSIONS
Oligoclonality of circulating CD8+ T cells is a characteristic feature of the human immune system; both host genetic factors and environment shape the pattern of oligoclonality in this T cell subset. The high frequency of this phenomenon in normal subjects provides a background with which to evaluate CD8+ T cell oligoclonality in the setting of infection or autoimmune disease. Further phenotypic and functional characterization of these clonally expanded T cells should provide insight into normal immune homeostasis.
Monteiro
J
J
Department of Medicine, North Shore University Hospital/Cornell University Medical Center, Manhasset, New York, USA.
Hingorani
R
R
Choi
I H
IH
Silver
J
J
Pergolizzi
R
R
Gregersen
P K
PK
D000293:Adolescent; D000328:Adult; D000595:Amino Acid Sequence; D001327:Autoimmune Diseases / Q000235:genetics / Q000276:immunology*; D001483:Base Sequence; D018414:CD8-Positive T-Lymphocytes / Q000276:immunology*; D003141:Communicable Diseases / Q000235:genetics / Q000276:immunology*; D017931:DNA Primers; D018076:DNA, Complementary; D006801:Humans; D008875:Middle Aged; D008969:Molecular Sequence Data; D016133:Polymerase Chain Reaction / Q000379:methods; D017260:Receptor-CD3 Complex, Antigen, T-Cell / Q000235:genetics*; D012016:Reference Values; D014430:Twins, Monozygotic / Q000235:genetics*
D017931:DNA Primers; D018076:DNA, Complementary; D017260:Receptor-CD3 Complex, Antigen, T-Cell