FEATURE OF
IMMUNOGLOBULIN HEAVY CHAIN COMPLEMENTARITY DETERMINING REGION 3 GENE IN
NEONATES WITH DIFFERENT GESTATIONAL AGE
Xiao X, Xiong AH, Zhou XG
First Affiliated Hospital of Medical College, Jinan University,
Guangzhou, China
Objective: To study the feature of immunoglobulin
complementarity determining region 3 (CDR3) gene in neonates with different
gestational age (GA), and the effect of neonatal maturity on the diversity
of CDR3 nucleotide sequence.
Methods: DNA were extracted from cord blood of 10
very immature neonates (25 – 30 weeks), 12 immature
(31 – 36 weeks), and mature (37 – 41 weeks), CDR3 sequence was amplified
using nested PCR technique, then cloned and sequenced.
Results: ①There was a CDR3 length of 29.4±7.8, 32.4±9.2 and 40.8±10.7bp, including an NDN length of 13.5±5.6,
16.1±7.8 and 22.0±8.5bp in
very immature, immature and mature neonates.②DP73
and DP75 were preferentially used in very immature and immature neonates, VH5, DP73 and DP75 in mature neonates. The
usage rate of DP73 and DP75 reduced, whereas VH5 was raised with GA increasing.③For D gene segment, there was a frequent
use of DN, DQ52 and DXP in very immature neonates, whereas DXP, DLR and DN
in immature and mature neonates. ④JH4 usage was preferential,
followed by JH6 in all neonates, and their usage rate was
decreased with GA increasing. ⑤63.3%、68.8% and 92.0% of CDR3
sequence in very immature，immature and mature neonates had an open
reading frame with 303bp long encoding 101 residues, respectively.
Conclusion: During the early life of neonates, VH-D-JH rearrangement of IgH
gene is in
an activated condition, but their diversity is limited. Humoral immunity is
a step by step developing with increasing GA. Both heterogeneity and
similarity of CDR3 sequence exists in neonates with different GA.