Shawn D. Balding

Analysis of antigens targeted by circulating IgG and IgA autoantibodies in 50 patients with cicatricial pemphigoid.

In this study we investigated sera from 50 typical cicatricial pemphigoid (CP) patients. By indirect immunofluorescence on 1 M NaCl-split human skin sections, IgG of 17 sera and IgA of 22 sera reacted with the epidermal side of the split, while IgG of two sera reacted with the dermal side. These latter two sera were later confirmed to be anti-epiligrin CP. By immunoblotting of epidermal extracts, IgG of 14 sera reacted with the 230 kD bullous pemphigoid (BP) antigen (BP230). IgG of 15 sera and IgA of 11 sera reacted with the 180 kD BP antigen (BP180). Interestingly, a bacterial fusion protein containing the BP180 NC16a domain was recognized by IgG of 18 sera but not by IgA of any sera. Fusion proteins containing the C-terminal region of BP180 were recognized by IgG of 20 sera, but it was detected by IgA of only two sera. Our results suggest that, although CP sera show very low titers of autoantibodies, a considerable number of sera contain IgG antibodies to BP180 (either NC16a or C-terminal domain), confirming previous studies. In addition, we showed that greater numbers of IgA antibodies react with BP180, seemingly with different types of epitopes from those for IgG antibodies. Because the specificity of IgG antibodies is not very different from those in BP, IgA antibodies may play a specific role for the development of characteristic clinical features in CP. Future studies should elucidate the pathogenic role of the IgA antibodies in CP.

L-cone pigment genes expressed in normal colour vision

To directly test the hypothesis that only two pigment genes are expressed from the X-chromosome array, we examined expressed M and L pigment gene sequences from > 100 male eye donors. In this sample, there were eight men who expressed high levels of more than one L pigment gene in addition to M pigment genes. The fact that these eyes expressed both L and M pigment genes at significant levels suggests they were from men with normal colour vision. We reject the hypothesis that only two pigment genes from one X-chromosome array can be expressed.

Topography of long- and middle-wavelength sensitive cone opsin gene expression in human and Old World monkey retina

The topographical distributions of the relative ratio of long- (L) and middle- (M) wavelength sensitive cone opsin messenger RNA (mRNA) in human and baboon retinas were mapped using real-time polymerase chain reaction. The L:M mRNA ratio increased in a central-to-peripheral gradient in both species, being quite pronounced for humans.

Pigment gene expression in protan color vision defects

We screened 150 male eye donors and identified four who did not have or express L pigment genes, consistent with each of them having a congenital protan color vision defect. One donor was identified as a protanope because he had and expressed a single X-chromosome photopigment gene that encoded an M pigment. Three were categorized as protanomalous because each expressed significant levels of genes specifying two spectrally different M pigments. The first gene in each of the protanomalous arrays was expressed the most and encoded an M pigment that differed in amino acid sequence from M pigments in color normal men.