Presentation of Lipid Antigens by CD1 – Antigen Processing and Presentation

00:01 It’s not only protein antigens of course that are recognized by the immune response.

00:05 Most types of molecules can be recognized.

00:08 So let’s look very briefly at what happens with lipid antigens.

00:13 Well again, they can be processed and presented.

00:17 The details are a little bit different but the overall concept is very similar.

00:22 So for example here we have a glycolipid or lipoprotein antigen, and this can be endocytosed or phagocytosed just like protein antigens or indeed whole intact microorganisms can be taken up by the cell.

00:38 So here we have the glycolipid or lipoprotein antigen, and this can be chewed up by lipases, rather than proteases chewing up proteins.

00:49 Lipases can chew up these particular types of antigen.

00:53 Meanwhile in the endoplasmic reticulum, the CD1 molecule is being produced.

00:58 Now this is a molecule that is very, very similar to MHC Class I.

01:02 It’s not an MHC Class I molecule, but it has a very similar structure.

01:06 It’s not identical structure, but a very similar structure.

01:08 And it can bind lipid antigens.

01:14 So again it needs to be exported, it needs to get together with the processed lipid antigen.

01:20 So it needs to be exported from the endoplasmic reticulum.

01:23 And then these two vesicles need to get together just as we saw previously with protein antigen and MHC Class II.

01:30 And the lipid antigens can be inserted into the binding groove of the CD1 molecule which is specialized to bind to lipid antigens, and then this will be taken to the cell surface where this combination of lipid plus CD1 can be presented to αβ T-cells, to γδ T-cells or indeed to NKT-cells.