Basic indices of spleen immune activity in natural populations of Norway rats (Rattus norvegicus berkenhout, 1769) in Serbia

Basic parameters of spleen immune activity (spleen weight, histomorphology of splenic compartments, and mitogen-induced splenocyte proliferative capacity in vitro) were evaluated in adult individuals of wild Norway rats from urban habitats and compared to the same data obtained in laboratory rat strains. A wider range of relative spleen mass and differential histomorphological characteristics, together with differences in the level and pattern of responsiveness of splenocytes to exogenous stimulation, were noted in spleens of wild Norway rats. Evidence of both enhanced and low-level immune-relevant spleen activity in wild rats demonstrates the complexity of changes in spleen immune activity in rats from natural populations.