Age groups differed in both the composition and functional state of the spleen. Within the red pulp, the amount of neutrophils and Table 1 . Antibodies and detection methods used to identify leukocytes and proliferating cells in the common shrew with references to suppliers and use in other species. [36, 53] . f [37] . g [53] . h [38] [39] [40] . megakaryocytes often appeared greater in adult animals than in sub-adults. The white pulp of sub-adults was exclusively comprised of secondary follicles, which often appeared interconnected and formed large groups (Fig. 1A) . These follicles were for the most part large and without signs of depletion and included numerous apoptotic cells and tingible body macrophages, as well as several mitotic cells. In contrast, the majority of adults exhibited fewer follicles which were a mixture of primary and secondary follicles (Figs. 1B, 2) and generally smaller than those of sub-adults (n = 17, Wald = 17.17, p,0.05, Figs. 1A, 2). Follicles in adults also differed from those in sub-adults, in that they were only partially surrounded by distinct perifollicular rims. Where present, germinal centres in adults contained both mitotic as well as apoptotic cells. Follicle centres in four adults exhibited collagen deposition, and while there was a tendency for greater follicle depletion in older animals (Fig. 2) , the difference between adults and sub-adults was not statistically significant (Wald = 2.10, not significant (ns)). The white pulp of the three pubescent animals exhibited primary and/ or secondary follicles, the latter with features similar to those found in sub-adult shrews. Males (n = 18) and females (n = 21) did not differ with respect to either size (Wald = 0.67, ns) or depletion (Wald = 0.13, ns) of follicles in the spleen.