Table 1.
Different treatment strategies under development for the prevention of human metapneumovirus (hMPV) infection
| Control strategy | Product | Human/animal model used | Results | Reference |
|---|---|---|---|---|
| Antivirals | Ribavirin | Tissue culture assay | Ribavirin along with intravenous immunoglobulin was found to have antiviral activity against hMPV in vitro | 84 |
| Human | Oral ribavirin combined with intravenous immunoglobulin led to rapid and complete recovery in an immunocompromised child who was undergoing chemotherapy for Burkitt's lymphoma | 85 | ||
| Antibodies | Monoclonal antibody | Mice | On immunization in BALB/c mice, showed significantly reduced lung viral titres, decreased histopathological changes, and decreased airway obstruction post challenge with hMPV | 86 |
| Hamster | Monoclonal antibodies against hMPV F protein showed protection against heterologous hMPV challenge in hamsters | 87 | ||
| Mice | Human monoclonal antibody was able to cross-neutralize hMPV and hRSV and may be used as prophylaxis and therapy for severe hRSV and hMPV | 88 | ||
| Fusion inhibitors | Inhibitory peptides | Mice | Fusion peptides against heptad repeat A and B domains of F protein gave protection against lethal hMPV intranasal challenge in BALB/c mice. Post-challenge there was a significant decrease in lung viral load, pulmonary inflammation, levels of proinflammatory cytokines, and airway obstruction | 89 |
| RNA interference | SiRNA | LLC-MK2 cells | SiRNA targeting P and N genes of hMPV was able to inhibit replication of all subgroups of HMPV in vitro | 90 |
| Mice | Dicer substrate SiRNA reduced lung viral titre post-challenge in mice | 91 | ||
| Inactivated vaccine | Heat inactivated vaccine | Mice | Immunization gave protective immunity against a homologous strain of hMPV followed by intranasal challenge in BALB/c mice | 92 |
| Epitope vaccine | T lymphocyte epitope vaccine | Mice | Immunization reduced viral load, lung pathology, and expression of Th2-type cytokines (IL-10, IL-4) after hMPV challenge | 93 |
| Chimeric vaccine | hMPV antigen on parainfluenza vaccine | African green monkeys, rhesus monkey | Intranasal immunization of African green monkeys induced hMPV-specific humoral and cell-mediated immune response and complete protection from wild-type hMPV challenge. In the rhesus monkey, this vaccine was found to be sufficiently attenuated | 94 |
| Subunit vaccine | hMPV F subunit vaccine | Hamster | Intranasal immunization with recombinant human PIV-1 expressing hMPV F protein vaccine showed high immunogenicity and protection in comparison to the ones expressing G and SH proteins | 95 |
| Cotton rats | Immunization showed reduced nasal viral shedding in cotton rats after hMPV challenge, while the lung pathology was comparable to that of control mice | 96 | ||
| Syrian golden hamsters | Immunization induced high virus neutralization titres against homologous virus. It also showed significantly reduced viral titres in nasal turbinates | 97 | ||
| Cynomolgus macaques | Immunization induced hMPV F specific antibody response, neutralizing antibody, and a robust cellular immune response. However, the induced humoral response waned rapidly over time | 98 | ||
| VLP | Virus-like particles (VLPs) | Mice | Immunization induced cross-protective immunity in mice against both homologous and heterologous strains, along with reduced viral titres in the lungs of immunized animals | 99 |
| Live attenuated vaccine | ΔM2-2 | Hamster | Attenuated and protective in hamsters against Wild type hMPV challenge | 18 |
| ΔG, ΔSH, ΔM2-2 | African green monkeys | ΔG and ΔM2-2 were sufficiently attenuated. After challenge with wild-type hMPV, virus shedding in the lower respiratory tract was undetectable | 101 | |
| ΔM2-2 | Mice | Immunization induced complete protection against challenge with a homologous strain and cross-protective immunity against a heterologous strain | 102 |
hRSV, human respiratory syncytial virus; SiRNA, small interfering RNA; IL, interleukin.