IN-VIVO MOLECULAR ANALYSIS OF CYTOKINES IN A MURINE MODEL OF OCULAR ONCHOCERCIASIS .1. UP-REGULATION OF IL-4 AND IL-5 MESSENGER-RNAS AND NOT IL-2 AND IFN-GAMMA MESSENGER-RNAS IN THE CORNEA DUE TO EXPERIMENTAL INTERSTITIAL KERATITIS

Sclerosing keratitis is the major cause of blindness due to onchocerci asis which results from chronic infection with the filarial parasite O nchocerca volvulus. Using a murine model of onchocercal sclerosing ker atitis, we have demonstrated previously that predominantly (> 85%) CD3 (+)/CD4(+) T-cells as well as the IL-2 receptor bearing cells infiltra te into the cornea in vivo during development and progress of the dise ase. The identification of CD4(+) subsets T(H)1 and T(H)2 based on the cytokine secretion patterns of murine T-lymphocytes has been useful f or understanding the immune basis of resistance and pathogenesis in mu rine models of several parasitic diseases. The present investigation w as carried out to demonstrate whether the local immune response at the corneal lesion due to onchocercal interstitial keratitis correlated w ith such distinct patterns of cytokine production. For that purpose, m RNA was extracted separately from corneas obtained from the diseased e yes and the normal eyes of A/J mice with onchocercal interstitial kera titis, reverse transcribed and amplified by the polymerase chain react ion with four different cytokine specific primers. In corneas obtained from the eyes affected with onchocercal interstitial keratitis, mRNAs coding for IL-4 and IL-5 were up-regulated compared to the normal eye s having no lesions from the same animals. However, the levels of mRNA s for IL-2 and IFN gamma were found to be the same in the diseased and normal eyes. Taken together, these data suggest that IL-4 and IL-5 pr oducing T(H)2-lymphocytes are active at the corneal lesion due to onch ocercal interstitial keratitis. Copyright (C) 1996 Elsevier Science B. V.