An outbreak of a mixed infection of Dermatophilus congolensis and Microsporum gypseum in camels (Camelus dromedarius) in Saudi Arabia

We isolated and identified the major protein present in corneas with granular dystrophy (GCD). We compared Coomassie-blue-stained protein bands obtained on sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) from the extracts of corneas with GCD, corneas with other disorders, and normal human corneal tissue. After SDS-PAGE and transfer to a polyvinylidene difluoride membrane, bands of interest were analyzed by amino acid sequencing and by Western blotting. Corneas with GCD were also examined immunohistochemically. On SDS-PAGE a 63-kd band just below albumin was present in extracts of all corneas. The albumin/63-kd ratio was normally approximately 3:1, suggesting that the protein is a dominant constituent of the cornea. This band was much more plentiful than normal in corneas with GCD. Amino-terminal sequence analysis of the protein revealed a Gly-Pro-Ala-Lys-Ser-Pro-Tyr-Gln-Leu-Val-Leu-Gln-His-Ser-Arg sequence indistinguishable from an amino-terminal protein sequence deduced from a cDNA clone designated beta ig-h3, and it as well as the abnormal accumulations in GCD cross-reacted with beta ig-h3 antiserum. The presence of excessive beta ig-h3 in human corneas with GCD together with reported mutations in the beta ig-h3 gene in GCD suggests that the mutated gene product is a fundamental constituent of the characteristic corneal accumulations in GCD.