Link Between Innate and Adaptive Immunity: Toll-Like Receptor 2 Internalizes Antigen for Presentation to CD4 super(+) T Cells and Could Be an Efficient Vaccine Target

• Published in: The Journal of immunology (1950) Vol. 171; no. 1; pp. 32 - 36
• Main Authors: Schjetne, K W, Thompson, K M, Nilsen, N, Flo, TH, Fleckenstein, B, Iversen, J-G, Espevik, T, Bogen, B
• Format: Journal Article
• Language: English
• Published: 01-07-2003
• ISSN: 0022-1767

An ideal vaccine for induction of CD4 super(+) T cell responses should induce local inflammation, maturation of APC, and peptide loading of MHC class II molecules. Ligation of Toll-like receptor (TLR) 2 provides the first two of these three criteria. We have studied whether targeting of TLR2 results in loading of MHC class II molecules and enhancement of CD4 super(+) T cell responses. To dissociate MHC class II presentation from APC maturation, we have used an antagonistic, mouse anti-human TLR2 mAb (TL2.1) as ligand and measured proliferation of a mouse C[kappa]-specific human CD4 super(+) T cell clone. TL2.1 mAb was 100-1000 times more efficiently presented by APC compared with isotype-matched control mAb. Moreover, TL2.1 mAb was internalized into endosomes and processed by the conventional MHC class II pathway. This novel function of TLR2 represents a link between innate and adaptive immunity and indicates that TLR2 could be a promising target for vaccines.