Chain-Specific Remodeling of the γδ T-Cell TCR Repertoire in Preterm Infants with cCMV

14 Apr 20264 min read0 viewsJournal Feed

GIST

BackgroundCongenital cytomegalovirus (cCMV) is a major cause of intellectual disability. γδ T-cells contribute to early-life antiviral defense, yet their T-cell receptor (TCR) repertoire in preterm cCMV remains incompletely defined.MethodsWe profiled the γδ T-cell TCR repertoire in preterm infants allocated to three non-overlapping groups: Congenital CMV infection (cCMV) group (n=9), Acquired CMV infection (aCMV) group (n=10), and Preterm controls (CMV-negative) (n=7).

RNA was extracted from RNAlater-stabilized heel-prick whole blood. Libraries were generated using constant-region–anchored primers for TRD/TRG, multiplex target enrichment, and index PCR, and sequenced on an Illumina platform (paired-end 150 bp).

Repertoire features included CDR3 length distributions, V(D)J usage, VJ pairing, and clonal diversity. Nine lineage-associated rearrangements were quantified by intercalating dye–based qPCR.ResultsTRD: the 25-aa CDR3 bin was less frequent in the cCMV group versus controls, and the cCMV group showed a lower Gini index, indicating less clonal dominance (greater evenness) than controls.

TRG: cCMV and aCMV differed in a length-interval–dependent manner. V-gene usage shifted by group (TRAV29/DV5 and TRAV38-2/DV8 in TRD; TRGV2/4/8/9 in TRG), and VJ pairings were more frequent in cCMV than in aCMV.

Clinical Editorial

Study design and scope

A gestational-age–stratified case–control approach examined γδ T-cell TCR repertoires in preterm infants allocated to three groups: congenital CMV infection (cCMV; n=9), acquired CMV infection (aCMV; n=10), and CMV-negative preterm controls (n=7).
RNA from heel-prick whole blood stabilized in RNAlater served as the input, with libraries generated via constant-region–anchored primers targeting TRD/TRG, followed by multiplex target enrichment and index PCR; sequencing used paired-end reads on an Illumina platform.
Repertoire metrics encompassed CDR3 length distributions, V(D)J gene usage, VJ pairings, and clonal diversity; nine lineage-associated rearrangements were quantified by intercalating-dye qPCR.

Key procedural findings

TRD analysis showed a reduction in the 25-amino-acid CDR3 bin in the cCMV group relative to controls.
In TRD, cCMV exhibited a lower Gini index compared with controls, indicating greater evenness and less clonal dominance.
TRG analysis revealed a length-interval–dependent difference between cCMV and aCMV.
V-gene usage differed by group: TRAV29/DV5 and TRAV38-2/DV8 prominent in TRD; TRGV2, TRGV4, TRGV8, and TRGV9 notable in TRG.
VJ pairing frequencies were heightened in cCMV versus aCMV.

Clonality and expression signals

The cCMV cohort harbored a higher number of “specific” clonotypes compared with controls (P = 0.020).
qPCR detected elevated expression of specific δ-chain pairings in cCMV, including Dδ2–Dδ3, Vδ2–Jδ1, and Vγ–Jγ1.3/2.3.
A mixed Vγ9+Vγ11–Jγ1.1/2.1 signal was also increased, though its deconvolution remains unresolved.

Interpretation and limitations

The study associates congenital CMV with chain-specific remodeling of the γδ T-cell repertoire in preterm infants.
Findings are potentially relevant for molecular risk stratification in neonatal CMV contexts.
Limitations include small sample size and reliance on RNA-level profiling