Antigenic determinant hidden

This number is equal to that of the precipitation zones, provided that what one is counting is actually antigen-antibody precipitation zones and not something else (see discussion of sources of error). The number of antigens determined is a minimum number because the concentration of the antibodies against one antigen (or of an antigen) may be below the threshold detectable value and because a precipitation zone may be hidden by others, especially when they are numerous. 

DEC is known to produce morphological changes on the surface of microfilariae. However, this change is not enough to cause death of the parasite [112]. It has also been shown that DEC enhances the specific IgG-mediated cell adherance on B.malayi microfilariae, which may be achieved by exposing the "hidden" antigenic determinant sites [119]. Martinez-Paloma [120] have shown that the immunogenic determinants of microfilariae of Onchocerca sp. are covered by an acellular cuticle. 

Richter has shown that by injecting SDS-dissociated subunits into rabbits antibodies are produced which are capable of precipitating subunits such antibody populations also precipitate ferritin or apoferri-tin. When antibodies directed against ferritin are absorbed out, there remain antibodies capable of precipitating subunits. It is presumed that antibodies which are precipitated only by subunits are directed against antigenic determinants in the subunits which are hidden in apoferritin monomers (165). 

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