Look at the immunofluorescence micrograph below.  It shows a group of human PBMCs (peripheral blood mononuclear cells), as the name suggests, these cells are isolated from peripheral blood and contain cells with large, round nuclei, such as lymphocytes, monocytes and macrophages).

The cells below have been stained with two different types of agents.  The first is called DAPI (4', 6-diamidino-2-phenylindole), this is a fluorescent dye that binds strongly to adenine/thymine-rich regions in DNA.  DAPI appears blue under fluorescent light.  The second is an antibody linked to a green fluorophore.  The antibody is against the human glycoprotein CD4, this antibody will bind to the surface of cells that express the CD4 glycoprotein on their surface.

(A)  Which region of the cells is visible due to staining with the DAPI stain?     (1 mark)

(B)  The primary antibody used to bind to the human CD4 glycoproteins on the cells is a monoclonal mouse antibody.  Its full description is a mouse anti-human CD4 IgG1 monoclonal antibody.

This primary antibody does not contain a fluorophore (nothing that will fluoresce under UV light).  Therefore a secondary antibody linked to a green fluorophore (called FITC - fluorescein isothiocyanate) has been used.

(i)  What is the secondary antibody raised against?     (1 mark)

(ii) Which species (e.g. mouse, human, goat, rabbit, donkey... etc) would the secondary antibody have been raised in?     (1 mark)