An immunoelectron micrograph of adult female worms

An immunoelectron micrograph of adult female worms including fetus and surrounding sheath, which are immunostained with anti phosphorylcholine monoclonal antibody, and secondary immunostained with anti mouseIgG antibody (biotin tagged).  The immunoreaction is visualised by the third reaction with avidin -gold complex.

    tissue         adult female worms
    1 st antibody    anti phosphorylcholine monoclonal antibody
    2nd antibody    anti mouse IgG antibody (biotin tagged)
    visual marker    colloidal gold   (avidin tagged)

The sheath is strongly positive by the immunostaining, suggesting the antigen is phosphorylcholin-related.
The fetus is negative by the immunostaining or very weakly positive if any.