Influenza Antibodies & Recombinant Proteins

Influenza or "flu" is a respiratory infection caused by the Orthomyxoviridae RNA virus family. Influenza virus can be classified into three main types: Influenza A, Influenza B, and Influenza C. Influenza viruses cause annual human epidemics. Seasonal influenza epidemics are primarily caused by influenza A and B viruses.

The influenza virus expresses two different types of antigens: hemagglutinin (HA) and neuraminidase (NA). The HA protein is responsible for viral attachment, whereas the NA protein facilitates viral release. In addition, both HA and NA proteins elicit immune responses, thus, reducing viral replication and preventing infection. Categorisation of the virus is dependent on their major antigenic differences. 3 to 5 million severe cases of seasonal influenza are noted each year causing thousands of deaths globally.

The Influenza A virus has 18 HA and 11 NA subtypes. New virulent strains of Influenza A are typically the cause of pandemics. As a result, public health experts are majorly concerned with Type A strains. Influenza virus subtypes, H1N1 and H3N2, actively circulate in humans while other subtypes (H9N2 and H7N7) cause sporadic human infection. Influenza A virus subtype H5N1 or "bird flu" is highly infectious and can cause severe disease in humans.

Hemagglutinin (HA) antibodies and proteins are the primary research tools for investigating the pandemic threat of various Type A strains, namely, H5N1, H9N2, and H7N7.

Alongside Influenza A, Influenza B viruses circulate annually during seasonal epidemics. Influenza B viruses can dominate influenza seasons causing severe disease. Depending on the genetic and antigenic variation of HA, Influenza B can be classified into two distinct lineages, Yamagata and Victoria. These lineages co-circulate globally.

The identification of subpopulations at high risk of infection with influenza is in high demand. As a result, biomarker detection and antibody testing are rapidly growing fields of research. KLRD1-expressing natural killer (NK) cells have been identified as a potential biomarker for influenza susceptibility. More recently, BPI and MMP8 have been described as significant candidate genes for severe influenza infection. These candidate genes are considered to be superior to conventional clinical indicators.