Primary Site of Coxsackievirus B Replication in the Small Intestines: No Proof of Peyer's Patches Involvement

Background: Enterovirus (EV) infections are associated with a broad range of diseases. Since the first experimental infection of primates with poliovirus (PV), tonsils and the Peyer's patches (PPs) have been believed to be the primary replication sites of EVs. Our aim was to localize different viral markers in the small intestines (SI) of coxsackievirus B (CVB) orally and intraperitoneally (i.p.) infected mice.Methods: Transverse sections of SIs of both infected and control male outbred mice were collected at different intervals post-infection (p.i) and analyzed for presence of interferon-alpha (IFN-α) and viral protein VP1 by immunohistochemistry and in situ hybridization (ISH). Fluorescent marker, eGFP, was identified in cryosections of mice infected with eGFP-CVB3.Results: In the infected SIs, we observed enlarged germinating centers (GCs) in the PPs; IFN-α was detected in the PPs and mucosal layer of the SIs. However, VP1, viral RNA and the eGFP were absent in the GCs of PPs at all stages of infection irrespective of the virus strains used.Conclusions: Virus was present in the epithelial cells but not in GCs of the PPs of the murine SIs. Our results do not support the hypothesis of EV replication in the PP especially in the GCs.</p

Monoclonal antibody against VP0 recognizes a broad range of human parechoviruses

Parechoviruses (PeVs) are common viruses that cause mild gastrointestinal or respiratory symptoms to severe central nervous system infections. In infants, parechovirus infection is one of the leading causes of lifethreatening viral disease. High-quality antibodies with broad binding specificities are essential to improve accurate parechovirus diagnosis in diagnostic laboratories. Such antibodies have potential in the development of rapid antigen detection assay against PeVs. In the present study, VP4 and VP2 genes from human parechovirus A1 (PeV-A1) were cloned and VP0 fusion protein produced to develop monoclonal antibodies against PeVs. Two pan-parechovirus antibodies, one IgG and one IgM isotype, were isolated. The properties of IgG1/kappa monoclonal (designated as Mab-PAR-1) was studied further. Mab-PAR-1 was shown to be functional in western blot against denatured recombinant protein and viral particles. In immunofluorescence assay, the antibody tested positive for nineteen PeV-A1 isolates while showing no cross-reactivity to fourteen entero- and rhinovirus types. In addition, Mab-PAR-1 showed positive reactivity against five other cultivable parechovirus types 2-6. A unique Mab-PAR-1 epitope located in the junction of the three capsid proteins VP0, VP1, and VP3 was identified using a peptide library screen. This study demonstrates that PeV-A1-VP0 protein is functional antigen for developing monoclonal antibody for diagnosis of broad range of parechovirus infections

Serological Follow-Up Study Indicates High Seasonal Coronavirus Infection and Reinfection Rates in Early Childhood

Seasonal human coronaviruses (HCoVs) cause respiratory infections, especially in children. Currently, the knowledge on early childhood seasonal coronavirus infections and the duration of antibody levels following the first infections is limited. Here we analyzed serological follow-up samples to estimate the rate of primary infection and reinfection(s) caused by seasonal coronaviruses in early childhood. Serum specimens were collected from 140 children at ages of 13, 24, and 36 months (1, 2, and 3 years), and IgG antibody levels against recombinant HCoV nucleoproteins (N) were measured by enzyme immunoassay (EIA). Altogether, 84% (118/140) of the children were seropositive for at least one seasonal coronavirus N by the age of 3 years. Cumulative seroprevalences for HCoVs 229E, HKU1, NL63, and OC43 increased by age, and they were 45%, 27%, 70%, and 44%, respectively, at the age of 3 years. Increased antibody levels between yearly samples indicated reinfections by 229E, NL63, and OC43 viruses in 20-48% of previously seropositive children by the age of 3 years. Antibody levels declined 54-73% or 31-77% during the year after seropositivity in children initially seropositive at 1 or 2 years of age, respectively, in case there was no reinfection. The correlation of 229E and NL63, and OC43 and HKU1 EIA results, suggested potential cross-reactivity between the N specific antibodies inside the coronavirus genera. The data shows that seasonal coronavirus infections and reinfections are common in early childhood and the antibody levels decline relatively rapidly. IMPORTANCE The rapid spread of COVID-19 requires better knowledge on the rate of coronavirus infections and coronavirus specific antibody responses in different population groups. In this work we analyzed changes in seasonal human coronavirus specific antibodies in young children participating in a prospective 3-year serological follow-up study. We show that based on seropositivity and changes in serum coronavirus antibody levels, coronavirus infections and reinfections are common in early childhood and the antibodies elicited by the infection decline relatively rapidly. These observations provide further information on the characteristics of humoral immune responses of coronavirus infections in children. The rapid spread of COVID-19 requires better knowledge on the rate of coronavirus infections and coronavirus specific antibody responses in different population groups. In this work we analyzed changes in seasonal human coronavirus specific antibodies in young children participating in a prospective 3-year serological follow-up study.Peer reviewe

No Association Between Ljungan Virus Seropositivity and the Beta-cell Damaging Process in the Finnish Type 1 Diabetes Prediction and Prevention Study Cohort

Background: Ljungan virus (LV) has not confirmed to associate with any human disease, but a possible connection with type 1 diabetes has been suggested. LV is a rodent-borne picornavirus that induces a diabetes-like condition in rodents. Approximately 30% of adults and 60% of children are seropositive in Finland. The Finnish Type 1 Diabetes Prediction and Prevention study enabled the use of very well characterized sample panels from children seroconverted to positivity for multiple islet autoantibodies during their prospective observation from birth; in addition, samples from age, sex, human leukocyte antigen (HLA), and residence area matched control children. Methods: We analyzed LV IgG seroprevalence in 102 case children (65 had also developed type 1 diabetes), in addition to nondiabetic control children. LV and human parechovirus (HPeV) immunofluorescence assays were used to analyze LV and HPeV-specific IgG from 102 plasma samples taken at the time of islet autoantibody appearance and from 204 samples from the matched control children. Results: Altogether 46.1% of the case and 50.7% of the control children were positive for LV IgG (odds ratio 0.8; 95% confidence interval, 0.47-1.36; P = 0.416) and 67.6% versus 79.8% were positive for HPeV IgG, respectively (odds ratio 0.49, 0.27-0.9, P = 0.023). Conclusions: Thus, no risk associations between LV or HPeV-specific IgG and islet autoimmunity were observed. However, a trend for significantly higher prevalence of HPeV antibodies in control children (P = 0.023) suggests a possible protective association of this virus with islet autoimmunity.Peer reviewe

Serological Follow-Up Study Indicates High Seasonal Coronavirus Infection and Reinfection Rates in Early Childhood

Seasonal human coronaviruses (HCoVs) cause respiratory infections, especially in children. Currently, the knowledge on early childhood seasonal coronavirus infections and the duration of antibody levels following the first infections is limited. Here we analyzed serological follow-up samples to estimate the rate of primary infection and reinfection(s) caused by seasonal coronaviruses in early childhood. Serum specimens were collected from 140 children at ages of 13, 24, and 36 months (1, 2, and 3 years), and IgG antibody levels against recombinant HCoV nucleoproteins (N) were measured by enzyme immunoassay (EIA). Altogether, 84% (118/140) of the children were seropositive for at least one seasonal coronavirus N by the age of 3 years. Cumulative seroprevalences for HCoVs 229E, HKU1, NL63, and OC43 increased by age, and they were 45%, 27%, 70%, and 44%, respectively, at the age of 3 years. Increased antibody levels between yearly samples indicated reinfections by 229E, NL63, and OC43 viruses in 20-48% of previously seropositive children by the age of 3 years. Antibody levels declined 54-73% or 31-77% during the year after seropositivity in children initially seropositive at 1 or 2 years of age, respectively, in case there was no reinfection. The correlation of 229E and NL63, and OC43 and HKU1 EIA results, suggested potential cross-reactivity between the N specific antibodies inside the coronavirus genera. The data shows that seasonal coronavirus infections and reinfections are common in early childhood and the antibody levels decline relatively rapidly. IMPORTANCE The rapid spread of COVID-19 requires better knowledge on the rate of coronavirus infections and coronavirus specific antibody responses in different population groups. In this work we analyzed changes in seasonal human coronavirus specific antibodies in young children participating in a prospective 3-year serological follow-up study. We show that based on seropositivity and changes in serum coronavirus antibody levels, coronavirus infections and reinfections are common in early childhood and the antibodies elicited by the infection decline relatively rapidly. These observations provide further information on the characteristics of humoral immune responses of coronavirus infections in children.The rapid spread of COVID-19 requires better knowledge on the rate of coronavirus infections and coronavirus specific antibody responses in different population groups. In this work we analyzed changes in seasonal human coronavirus specific antibodies in young children participating in a prospective 3-year serological follow-up study.</p

COVID-19 mRNA vaccine induced antibody responses against three SARS-CoV-2 variants

As SARS-CoV-2 has been circulating for over a year, dozens of vaccine candidates are under development or in clinical use. The BNT162b2 mRNA COVID-19 vaccine induces spike protein-specific neutralizing antibodies associated with protective immunity. The emergence of the B.1.1.7 and B.1.351 variants has raised concerns of reduced vaccine efficacy and increased re-infection rates. Here we show, that after the second dose, the sera of BNT162b2-vaccinated health care workers (n = 180) effectively neutralize the SARS-CoV-2 variant with the D614G substitution and the B.1.1.7 variant, whereas the neutralization of the B.1.351 variant is five-fold reduced. Despite the reduction, 92% of the seronegative vaccinees have a neutralization titre of >20 for the B.1.351 variant indicating some protection. The vaccinees’ neutralization titres exceeded those of recovered non-hospitalized COVID-19 patients. Our work provides evidence that the second dose of the BNT162b2 vaccine induces cross-neutralization of at least some of the circulating SARS-CoV-2 variants

COVID-19 mRNA vaccine induced antibody responses against three SARS-CoV-2 variants

As SARS-CoV-2 has been circulating for over a year, dozens of vaccine candidates are under development or in clinical use. The BNT162b2 mRNA COVID-19 vaccine induces spike protein-specific neutralizing antibodies associated with protective immunity. The emergence of the B.1.1.7 and B.1.351 variants has raised concerns of reduced vaccine efficacy and increased re-infection rates. Here we show, that after the second dose, the sera of BNT162b2-vaccinated health care workers (n=180) effectively neutralize the SARS-CoV-2 variant with the D614G substitution and the B.1.1.7 variant, whereas the neutralization of the B.1.351 variant is five-fold reduced. Despite the reduction, 92% of the seronegative vaccinees have a neutralization titre of >20 for the B.1.351 variant indicating some protection. The vaccinees' neutralization titres exceeded those of recovered non-hospitalized COVID-19 patients. Our work provides evidence that the second dose of the BNT162b2 vaccine induces cross-neutralization of at least some of the circulating SARS-CoV-2 variants. Emerging SARS-CoV-2 variants contain mutations in the spike protein that may affect vaccine efficacy. Here, Jalkanen et al. show, using sera from 180 BNT162b2-vaccinated health care workers, that neutralization of SARS-CoV2 variant B.1.1.7 is not affected, while neutralization of B.1.351 variant is five-fold reduced.Peer reviewe

Detection of enteroviruses in stools precedes islet autoimmunity by several months : possible evidence for slowly operating mechanisms in virus-induced autoimmunity

Julkaisua hallinoi Tampereen yliopisto!Aims/hypothesis This case-control study was nested in a prospective birth cohort to evaluate whether the presence of enteroviruses in stools was associated with the appearance of islet autoimmunity in the Type 1 Diabetes Prediction and Prevention study in Finland. Methods Altogether, 1673 longitudinal stool samples from 129 case children who turned positive for multiple islet autoantibodies and 3108 stool samples from 282 matched control children were screened for the presence of enterovirus RNA using RT-PCR. Viral genotype was detected by sequencing. Results Case children had more enterovirus infections than control children (0.8 vs 0.6 infections per child). Time-dependent analysis indicated that this excess of infections occurred more than 1 year before the first detection of islet autoantibodies (6.3 vs 2.1 infections per 10 follow-up years). No such difference was seen in infections occurring less than 1 year before islet autoantibody seroconversion or after seroconversion. The most frequent enterovirus types included coxsackievirus A4 (28% of genotyped viruses), coxsackievirus A2 (14%) and coxsackievirus A16 (11%). Conculusion/hypothesis The results suggest that enterovirus infections diagnosed by detecting viral RNA in stools are associated with the development of islet autoimmunity with a time lag of several months.Peer reviewe

COVID-19 mRNA vaccine induced antibody responses against three SARS-CoV-2 variants

As SARS-CoV-2 has been circulating for over a year, dozens of vaccine candidates are under development or in clinical use. The BNT162b2 mRNA COVID-19 vaccine induces spike protein-specific neutralizing antibodies associated with protective immunity. The emergence of the B.1.1.7 and B.1.351 variants has raised concerns of reduced vaccine efficacy and increased re-infection rates. Here we show, that after the second dose, the sera of BNT162b2-vaccinated health care workers (n=180) effectively neutralize the SARS-CoV-2 variant with the D614G substitution and the B.1.1.7 variant, whereas the neutralization of the B.1.351 variant is five-fold reduced. Despite the reduction, 92% of the seronegative vaccinees have a neutralization titre of >20 for the B.1.351 variant indicating some protection. The vaccinees' neutralization titres exceeded those of recovered non-hospitalized COVID-19 patients. Our work provides evidence that the second dose of the BNT162b2 vaccine induces cross-neutralization of at least some of the circulating SARS-CoV-2 variants. Emerging SARS-CoV-2 variants contain mutations in the spike protein that may affect vaccine efficacy. Here, Jalkanen et al. show, using sera from 180 BNT162b2-vaccinated health care workers, that neutralization of SARS-CoV2 variant B.1.1.7 is not affected, while neutralization of B.1.351 variant is five-fold reduced.</p