T cell cross-reactivity among viruses of the paramyxoviridae

Can early measles vaccination control both measles and respiratory syncytial virus infections?

Measles virus and respiratory syncytial virus (RSV) are two important global health pathogens causing substantial morbidity and mortality worldwide. The current measles vaccination schedule has the first dose given at 9–12 months of age and the second dose given at 15–18 months of age. Measles outbreaks have been associated with an increase in severe RSV infections in children younger than 6 months, probably as a result of measles-induced immunosuppression. A resurgence in measles cases was already occurring before the COVID-19 pandemic, which has affected global immunisation programmes, resulting in millions of children, mostly in low-income and middle-income countries (LMICs), missing out on their measles vaccine. This will leave many children living in the most vulnerable of circumstances highly susceptible to measles and RSV infections when current COVID-19 public health control measures are lifted. This Viewpoint discusses these issues and highlights the need for urgent action to address this looming crisis. The use of early measles vaccination at 4 months of age could be an effective strategy to prevent severe morbidity and death from both measles and RSV infections in many LMICs.

T-Cell Therapeutics Targeting Human Parainfluenza Virus 3 Are Broadly Epitope Specific and Are Cross Reactive With Human Parainfluenza Virus 1

Human Parainfluenza Virus-3 (HPIV3) causes severe respiratory illness in immunocompromised patients and lacks approved anti-viral therapies. A phase I study of adoptively transferred virus-specific T-cells (VSTs) targeting HPIV3 following bone marrow transplantation is underway (NCT03180216). We sought to identify immunodominant epitopes within HPIV3 Matrix protein and their cross-reactivity against related viral proteins. VSTs were generated from peripheral blood of healthy donors by ex-vivo expansion after stimulation with a 15-mer peptide library encompassing HPIV3 matrix protein. Epitope mapping was performed using IFN-γ ELIspot with combinatorial peptide pools. Flow cytometry was used to characterize products with intracellular cytokine staining. In 10 VST products tested, we discovered 12 novel immunodominant epitopes. All products recognized an epitope at the C-terminus. On IFN-γ ELISpot, individual peptides eliciting activity demonstrated mean IFN-γ spot forming units per well (SFU)/1x10⁵ cells of 115.5 (range 24.5-247.5). VST products were polyfunctional, releasing IFN-γ and TNF-α in response to identified epitopes, which were primarily HLA Class II restricted. Peptides from Human Parainfluenza Virus-1 corresponding to the HPIV3 epitopes showed cross-reactivity for HPIV1 in 11 of 12 tested epitopes (mean cross reactivity index: 1.19). Characterization of HPIV3 epitopes may enable development of third-party VSTs to treat immune suppressed patients with HPIV infection.

Effect of an Early Dose of Measles Vaccine on Morbidity Between 18 Weeks and 9 Months of Age: A Randomized, Controlled Trial in Guinea-Bissau

Background

Children in Guinea-Bissau receive measles vaccine (MV) at 9 months of age, but studies have shown that an additional dose before 9 months of age might have beneficial nonspecific effects. Within a randomized trial designed to examine nonspecific effects of early MV receipt on mortality, we conducted a substudy to investigate the effect of early MV receipt on morbidity.

Methods

Children were randomly assigned at a ratio of 2:1 to receive 2 doses of MV at 18 weeks and age 9 months (intervention group) or 1 dose of MV at age 9 months, in accordance with current practice (control group). Children were visited weekly from enrollment to age 9 months; the mother reported morbidity, and the field assistants examined the children. Using Cox and binomial regression models, we compared the 2 randomization groups.

Results

Among the 1592 children, early measles vaccination was not associated with a higher risk of the well-known adverse events of fever, rash, and convulsions within the first 14 days. From 15 days after randomization to age 9 months, early measles vaccination was associated with reductions in maternally reported diarrhea (hazard ratio [HR], 0.89; 95% confidence interval [CI], .82-.97), vomiting (HR, 0.86; 95% CI, .75-.98), and fever (HR, 0.93; 95% CI, .87-1.00).

Conclusion

Early MV receipt was associated with reduced general morbidity in the following months, supporting that early MV receipt may improve the general health of children.

Measles-mumps-rubella vaccination and respiratory syncytial virus-associated hospital contact

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MMR vaccination is given to protect against measles, mumps and rubella.

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RSV is an important cause of acute lower respiratory infections in young children.

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MMR vaccination was associated with 22% lower rate of RSV hospital contacts.

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MMR vaccination may reduce the rate or severity of RSV infection.

Background

The live measles vaccine has been associated with lower non-measles mortality and admissions in low-income countries. The live measles–mumps–rubella vaccine has also been associated with lower rate of admissions with any type of infection in Danish children; the association was strongest for admissions with lower respiratory infections.

Objective

To examine whether measles, mumps, and rubella (MMR) vaccination was associated with reduced rate of hospital contact related to respiratory syncytial virus (RSV) in a high-income country.

Methods

Nationwide cohort study of laboratory-confirmed RSV hospital contacts at age 14–23 months in all children born in Denmark 1997–2002 who had already received the vaccine against diphtheria, tetanus, pertussis (acellular), polio, and Haemophilus influenzae type b (DTaP-IPV-Hib) at the recommended ages of 3, 5, and 12 months.

Results

The study included 888 RSV hospital contacts in 128,588 person years of follow up (rate 6.8/1000 person years). Having MMR as the most recent vaccine was associated with a reduced rate of RSV hospital contacts compared with having DTaP-IPV-Hib as the most recent vaccine (Incidence rate ratio (IRR), 0.75; 95% confidence interval (CI), 0.63–0.89). After adjustment for potential confounders including exact age in days the IRR was 0.78 (95% CI, 0.66–0.93). The adjusted IRR was 0.74 (95% CI, 0.60–0.92) in males and 0.84 (95% CI, 0.66–1.06) in females (P Interaction, 0.42). There was no association in the first month after MMR vaccination (adjusted IRR, 0.97; 95% CI, 0.76–1.24) but the adjusted IRR was 0.70 (95% CI, 0.58–0.85) from one month after MMR vaccination.

Conclusions

MMR vaccination was associated with reduced rate of hospital contacts related to laboratory-confirmed RSV infection. Further research on the association between MMR vaccination and other unrelated pathogens are warranted.

Morbillivirus cross-species infection: is there a risk for humans?

The WHO has set regional elimination goals for measles eradication to be achieved by 2020 or earlier. A major question is whether an opportunity for veterinary virus infection of humans may arise when measles is eradicated and if vaccination is discontinued. Lessons have been learned from animal to human virus transmission i.e., HIV and more recently from severe acute respiratory syndrome and avian influenza virus infections. We are therefore alerted to the risk of zoonosis from the veterinary morbilliviruses. In this review the evidence from viral genomics, animal studies and cell culture experiments will be explored to evaluate the possibility of cross-infection of humans with these viruses.

Prior infection by respiratory syncytial virus or parainfluenza viruses augments virus-specific IgG responses induced by the measles/mumps/rubella vaccine

We found previously that immunizing cyclophosphamide-treated mice with one Paramyxoviridae virus mixed with dimethyl dioctadecyl ammonium bromide induces T cells which apparently also recognize other Paramyxoviridae viruses. This finding and the fact that respiratory syncytial virus (RSV) and parainfluenza viruses (PIVs) infect children early in life led us to ask if prior RSV or PIV infections influence the antibody response to measles and mumps vaccine viruses. Detection of virus-specific IgG in serum specimens collected randomly or at defined times after measles/mumps/rubella (MMR) vaccination was done with solid-phase enzyme immunoassays. The antibody-binding data obtained were converted to serum antibody titers by an immunoassay curve-fitting computer program. Prior infection by RSV and PIVs correlated with an augmented IgG response not only to measles and mumps virus, but also to rubella virus. Furthermore, the augmentation was greater for responders below the median response. These data show that common early childhood viral infections can influence immunity induced by the MMR vaccine.

Replication of measles virus in the human plasma cell leukemia-derived LICR-LON-HMy2 cell line

Measles virus is usually grown in human or monkey fibroblast cells. We now show that LICR-LON-HMy2 (LL2) cells, a human plasma cell leukemia-derived line which grows in suspension culture, will permissively support replication of measles virus to an extent achievable with Vero cells. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis of measles virions produced by LL2 cells showed a polypeptide pattern typical of measles virus. As well, measles virus-infected LL2 cells, like infected Vero cells, were found to secrete large amounts of virus hemagglutinin, but not other virus proteins. We thus conclude that LL2 cells can be effectively used to produce milligram amounts of measles virus and that virus-clarified culture medium from measles virus-infected LL2 cells is a potential source for purifying virus hemagglutinin.