Congenital cytomegalovirus infection - An update

An Elastin-like Polypeptide-fusion peptide targeting capsid-tegument interface as an antiviral against cytomegalovirus infection

The tegument protein pp150 of Human Cytomegalovirus (HCMV) is known to be essential for the final stages of virus maturation and mediates its functions by interacting with capsid proteins. Our laboratory has previously identified the critical regions in pp150 important for pp150-capsid interactions and designed peptides similar in sequence to these regions, with a goal to competitively inhibit capsid maturation. Treatment with a specific peptide (PepCR2 or P10) targeted to pp150 conserved region 2 led to a significant reduction in murine CMV (MCMV) growth in cell culture, paving the way for in vivo testing in a mouse model of CMV infection. However, the general pharmacokinetic parameters of peptides, including rapid degradation and limited tissue and cell membrane permeability, pose a challenge to their successful use in vivo. Therefore, we designed a biopolymer-stabilized elastin-like polypeptide (ELP) fusion construct (ELP-P10) to enhance the bioavailability of P10. Antiviral efficacy and cytotoxic effects of ELP-P10 were studied in cell culture, and pharmacokinetics, biodistribution, and antiviral efficacy were studied in a mouse model of CMV infection. ELP-P10 maintained significant antiviral activity in cell culture, and this conjugation significantly enhanced P10 bioavailability in mouse tissues. The fluorescently labeled ELP-P10 accumulated to higher levels in mouse liver and kidneys as compared to the unconjugated P10. Moreover, viral titers from vital organs of MCMV-infected mice indicated a significant reduction of virus load upon ELP-P10 treatment. Therefore, ELP-P10 has the potential to be developed into an effective antiviral against CMV infection.

Genotypes of glycoprotein B gene among the Indian symptomatic neonates with congenital CMV infection

BACKGROUND

Cytomegalovirus [CMV] is a causative agent of congenital infection worldwide and often leads to neurological deficits and hearing loss in newborns. Infants born with symptomatic congenital Cytomegalovirus infection [cCMV] are at significant high risk for developing adverse long-term outcomes. In this study, we look into the sequence variability of surface glycoprotein B [gB] encoding region in newborns with symptomatic CMV infection for the first time in Eastern region of India.

METHODS

576 suspected newborns from seropositive mothers were subjected to the study and ELISA was used to confirm CMV infection. Different genotypes and their subtypes were determined using multiplex nested-PCR. Viral load of different glycoprotein B [gB] genotypes was measured using RT-PCR. Sequencing and phylogenetic analysis was then performed using Bayesian interference.

RESULTS

The overall frequency of cCMV infection was 18.4%, where 16.0% neonates were symptomatic. Among the different gB genotypes, gB1 had the highest frequency [23.5%] and gB4 showed the lowest occurrence [5.8%]. 23.5% of symptomatic neonates had mixed genotypes of gB, probably indicating matrenal reinfection with CMV strains in Indian population. Significant genotypic clades [gB1-gB2-gB3-gB5] were grouped closely based on gene sequences, but the gB4 sequence was in the outlier region of the phylogenetic tree indicating the genetic polymorphism.

CONCLUSION

This is the first study on cCMV genotyping and its phylogenetic analysis from Eastern Indian neonatal population. The study holds importance in the assessment of cCMV seroprevalence in global perspective. gB protein can be used as a potential therapeutic target against CMV infection.

Glycoprotein B genotyping in congenital/perinatal Cytomegalovirus infection in symptomatic infants

BACKGROUND

Molecular epidemiological studies on circulating strains of CMV in cogenital/perinatal infections have not been done earlier in this region.

OBJECTIVE

To study the glycoprotein B genotypes in babies with symptomatic congenital/perinatal CMV infection and to assess the possible influence of genotype on the outcome of the infection.

METHODS

Clinical samples (blood and urine) of symptomatic babies are sent to the Virology Department of NCDC, Delhi for the diagnosis of congenital infections. 375 clinical samples of infants (newborn - 6 months old) were included for the study. Serum samples were subjected to ELISA for detection of IgM antibodies against CMV. DNA isolation and amplification of CMV genomic DNA targeting gB gene fragment by nested PCR, was carried out in the samples. The amplified fragment including the cleavage site was subjected to RFLP using restriction enzymes Rsal and Hinf1. They were also verified by sequencing using Big Dye Terminator chemistry.

RESULTS

75 samples out of 375 tested were confirmed positive for CMV infection by serology and PCR. Both RFLP and sequencing of gB gene fragment showed that gB 1, 2 and 3 genotypes were in circulation. gB 3 was the most prevalent genotype in symptomatic infants. Hepatosplenomegaly was the most common feature in gB-3 genotype of CMV. gB2 congenital CMV infection was more commonly associated with long term sequelae.

Congenital CMV infection in symptomatic infants in Delhi and surrounding areas

Many viral infections are associated with significant maternal and fetal consequences during pregnancy among which cytomegalovirus is one of the most important agent, globally. Both primary and recurrent infection due to this virus can result in fetal infection. Samples from Congenital Anoammaled babies are referred to NICD from Delhi based Government hospitals and surrounding areas for diagnosis of congenital infections like Toxoplasm, Rubella, CMV and Herpes. In the present study, accumulated data is presented for the most common teratogenic virus--Cytomegalovirus prevalence as a causative agent for congenital infection in New Born babies at Delhi and surrounding areas. 96 samples from symptomatic babies in the age group of few days to 6 months exhibiting different congenital anomalies, were reported between 1 st Jan 04 to 30 th April/05. All the blood samples were tested for the detection of CMV (IgM) antibodies using m-capture ELISA technique. 18(18.75%) samples from babies showed positive titres for CMV-IgM antibodies. None of the mothers of positive babies were found positive for CMV-IgM antibodies but all were serologically exposed to CMV virus previously as their serum samples were positive for CMV-IgG antibodies indicating primary infection in the past or reactivation/reinfection with a different strain of CMV in the early pregnancy.