Fig.1 Human parainfluenza virus virion and genome organization.
Fig.2 Schematic illustration of the parainfluenza life cycle.
The human parainfluenza virus (HPIV), currently known as the human respirovirus, is a group of pathogenic viruses belonging to the family Paramyxoviridae. Since firstly discovered in the late 1950s from children with croup, 5 serotypes and subtypes have been identified based on antigenic and genetic properties: HPIV1, HPIV2, HPIV3, HPIV4a, and HPIV4b. Among these subtypes, HPIV1 and HPIV3 genus belong to the genus of Respirovirus, whereas, HPIV2, HPIV4a, and HPIV4b are members of the genus of Rubulavirus. All of these five HPIVs are important respiratory pathogens for both human and veterinary.
HPIVs are commonly associated with respiratory illness in children and adults, causing multiple symptoms, such as fever, cough, runny nose, stuffy nose, sneezing, sore throat, pneumonia, etc. Usually, one-third of the infections are caused by HPIV1, HPIV2, and HPIV3. HPIV1 and HPIV3 are identified as the major causes of bronchitis and bronchopneumonia; HPIV1 and HPIV2 are closely related to croup (laryngotracheobronchitis); HPIV-3 is not so common and may associate with upper respiratory disease. These pathogenic HPIVs transmit via close contact through respiratory droplets or secretions. All these HPIVs and infections can be diagnosed by several clinical and laboratory methods, including electron microscopy, immunofluorescence (IF), polymerase chain reaction (PCR), hemagglutination inhibition test (HAI), hemadsorption inhibition assay, complement fixation (CFT), enzyme-linked immunosorbent assay (ELISA).
Structurally, HPIVs are pleomorphic enveloped viruses with a diameter ranging from 150 to 200 nm. Inside the enveloped shell is a single-stranded negative-sense RNA genome of the HPIV. The HPIV genome contains about 15,000 nucleotides in length organized into a sequence of 3’-NP-P-M-F-HN-L-5’, which encodes at least 6 essential viral proteins as follows:
1. The hemagglutinin neuraminidase (HN) glycoprotein on the surface of the envelope is responsible for the attachment of the HPIV to the host cell;
2. The fusion glycoprotein (F) located on the surface of the virus in the form of trimer mainly mediates the fusion of the viral particles to the host cell membrane. The HN protein and F protein on the surface of the enveloped shell are the major targets/antigens for the antibodies;
3. The matrix protein (M) within the envelope is involved in virus assembly;
4. The nucleocapsid protein (NP) coating the viral RNA forms a complex with the RNA genome and creates a template for RNA-dependent RNA polymerase;
5. The large protein (L), also named as RNA polymerase, is a part of RNA polymerase complex;
6. The phosphoprotein (P), together with L protein, involves forming the RNA polymerase complex of the nucleocapsid.
Researches demonstrated that antibodies specific target the HPIV or surface HN protein and F protein can be used for neutralizing viral particles. More importantly, those clinical and laboratory diagnostic tests and assays all need anti-HPIV antibodies with high specificity. Creative Biolabs has developed a spectrum of monoclonal and polyclonal antibodies against HPIV with our high-tech antibody platform. Also, we provide customization antibody service based on clients’ demands.
For specific HPIV antibody products, please feel free to contact us. We will reply to you as soon as possible.