Identification and sequence analysis of an Mhc class II B gene in a marsupial (Monodelphis domestica)

Previous studies from our laboratory have shown dramatic differences between the immune responses of the South American marsupial Monodelphis domestica (hereafter referred to as Monodelphis) and eutherian mammals. For example, Monodelphis exhibits a typical primary immune response to particulate immunogens, but a relatively weak and short-lived secondary response. Even more dramatic is the virtual absence of a mixed lymphocyte response despite the normal rejection of allogenic skin transplants. The latter observations suggest that either the T-cell receptor or the Mhc class II molecules, or both, are atypical. In search of a molecular explanation for this atypical behavior, we attempted to clone and characterize the genes of Monodelphis that are involved in the immune response. This paper reports the sequence of a major histocompatibility complex (Mhc) class II B gene of Monodelphis obtained froma cDNA library.