Interferon type III
The recently classified type III interferon group consists of three IFN-λ (lambda) molecules called IFN-λ1, IFN-λ2 and IFN-λ3 (also called IL29, IL28A and IL28B respectively). These IFNs signal through a receptor complex consisting of IL10R2 (also called CRF2-4) and IFNLR1 (also called CRF2-12). 
Acceptance of this classification is less universal than that of type I and type II, and unlike the other two, it is not currently included in Medical Subject Headings.
- Vilcek, Novel interferons. Nature Immunology, 2003, Volume 4, pages 8-9
- Bartlett et al., Murine interferon lambdas (type III interferons)exhibit potent antiviral activity in vivo in a poxvirus infection model. Journal of General Virology, 2005, Volume 86 pages 1589–1596