Expression of MhcCyca class I and class II molecules in the early life history of the common carp (Cyprinus carpio L.)

In this study transcription of class I proportional to chain (Cyca-UA), bet a(2)-microglobulin (Cyca-B2m) and class II proportional to (Cyca-DXA) and b eta (Cyca-DAB) during the early stages of embryo development was investigat ed by semi-quantitative PCR, No transcripts of the genes under investigatio n were detected in the unfertilized egg. The expression of the genes encodi ng for the class LI molecules revealed to be synchronized starting at day I , unlike those for the class I molecules. Transcription of Cyca-B2m was fir st detected at day 7, whereas Cyca-UA was already present on day 1. This di screpancy mould suggest absence of class I molecules during early developme nt, The transcription of the Mite genes in lymphoid organs was well establi shed on day 21, with the exception of the spleen. In later stages of ontoge ny cell surface expression of class I molecules was studied using polyclona l antibodies to Cyca-UA and Cyca-B2m in conjunction with detection of surfa ce Tg. In week 3-10 Cyca-B2m was found on a higher percentage of cells from pronephros, spleen and thymus compared to Cyca-UA, suggesting the use of a n alternative class I proportional to chain, In the thymus, unlike the othe r organs, this difference remained present in the adult stage. The most lik ely candidates are a chains encoded by non-classical class I genes. (C) 199 8 Elsevier Science Ltd. All rights reserved.