Scientists Discover New Type Of ‘Cross-Presenting’ White Blood Cell

Researchers in Newcastle and Singapore have identified a new type of white blood cell that activates a killing immune response to an external source.
Researchers have identified a new type of white blood cell that activates a killing immune response to an external source – a feature known as ‘cross-presentation.’
Publishing in the journal Immunity, the team of researchers from Newcastle University and A*STAR’s Singapore Immunology Network (SIgN) describe a new human tissue dendritic cell with cross-presenting function.
Dendritic cells (DCs) are a type of white blood cell that orchestrate our body’s immune responses to infectious agents such as bacteria, viruses, and cancer cells. The cells kick start an immune response by presenting small fragments of the foreign micro-organism – called antigens – on their surface, which then activate T cells that eliminate the cancerous or infected cells.
Unlike most cells which are only able to present antigens from within themselves, and so will only elicit an immune response if they are infected, a specialized subset of DCs is able to generate a response to an external source of antigen. But the identity of human tissue DCs that are capable of ‘cross-presentation’ has remained a mystery until now.

“These are the cells we need to be targeting for anti-cancer vaccines,” said lead author Dr. Muzlifah Haniffa of Newcastle University. “Our discovery offers an accessible, easily targetable system which makes the most of the natural ability of the cell.”

The researchers also showed for the first time that dendritic cell subsets are conserved between humans and mice.
To compare between species, the team isolated cross-presenting DCs from human skin and also from mouse blood, lung, and liver. Using gene expression analysis, they identified gene signatures for each human dendritic cell subset. Mouse orthologues of these genes were identified and computational analysis was used to match subsets across species.

“The cross-species map is in effect a Rosetta stone that deciphers the language of mouse into human,” said senior co-author Matthew Collin, who is a professor of hematology at Newcastle University.