Experimental infections in rodents with Echinococcus multilocularis sibiricensis, Echinococcus granulosus canadensis, and Echinococcus granulosus (Lebanon origin) both by ingestion of onchospheres and by parenteral injection are recorded. The microscopic anatomy of the larval parasite and of the host reaction are discussed and illustrated in detail. Voles and cotton rats display little resistance to the development of the cyst of E. m. sibiricensis and ultimately destroy the host, while collared lemmings and golden hamsters overcome the cyst and destroy it. Muskrats and certain white mice are intermediate in their effects. In all cases, however, some degree of degeneration of the parasite into the alveolar form is shown. White rats, guinea pigs, and rabbits could not be infected with this parasite. E. g. canadensis was developing in the lung of one AKR strain mouse while in the chinchilla the parasite commenced to develop in the lung but was overcome at an early stage. No development took place in the other species of hosts. E. granulosus (Lebanon) appeared to be developing successfully in some cotton rats and white mice fed on onchospheres.

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SUMMARYThis investigation used flow cytometry to monitor peripheral hlood lymphocyte morphology after rat small bowel transplinitation. Preliminary studies demonsirated that in vitro activated peripheral blood lymphocytes exhibited increased cell size and granularity as measured by flow cytometric analysis of forward (FSc) and side (SSc) light scatter characteristics. The formation of distinct 'activated" light scatter regions by such lymphoblastoid transformation occurred concomitantly with up-regulaied p55IL-2R expression. Heterotopic small bowel transplantation was performed between PVG donor and DA recipient rats without immunosuppression. Animals receiving isografts served as controls. Peripheral blood lymphocyte subsets were identified using appropriate MoAbs. and the light scatter characteristics of each cell subset were determined by backgating strategies. Increased proportions of activated tt/ii T ceil receptor (TCR)-positive cells could be detected inallografted animalsasearly as day 2 post-transplantation. B cells showed peak activation by day 4. at which time the proportion of activated cells was over two-fold greater than that seen in untransplanted animals few activated B cells were detected in isografted animals. Resting natural killer (NK) cell light scatter regions only partially overlap with those of resting T and B lymphocytes, but in allografted animals almost the entire NK population fell outside the resting lymphocyte gate by day 2 post-transplantation, an activation state which was maintained until day 4. These findings associate peripheral blood cell subset lymphoblastoid transformation wilh developing small bowel allograft rejection. Importantly, changes were detected early and prior to the onset of overt rejection. These data suggest that analysis of peripheral blood lymphocyte light scatter properties may provide an insight into in vivo immune status after small bowel transplantation.

This study used flow cytometry to identify graft cells in the recipient peripheral blood and spleen and host cells infiltrating the graft mesenteric lymph node and Peyer's patches after heterotopic rat small bowel transplantation. Transplantation had little effect on the overall cell subset composition of these compartments and no changes appeared characteristic or indicative of developing rejection, suggesting that physiological control of cell migration remained unaltered. A small and transient population of graft cells was detected in the peripheral blood and spleen of the recipient which disappeared after 5 and 3 days respectively. Graft-derived cells in the peripheral blood comprised predominantly CD4+ cells on day 1 with B cells predominating on day 5. Graft cells infiltrating the spleen were predominantly B cells. Host cells infiltrated the graft mesenteric lymph nodes and Peyer's patches to a lesser extent than previously reported using immunohistochemical analysis. For both tissues, infiltrating host-derived cells initially comprised mainly CD4+ cells. On day 4 approximately equal proportions of CD4+ and B cells were present in the mesenteric lymph node, whereas B cells were predominant in the host cell infiltrate of the graft Peyer's patches. In summary, these findings indicate that the cell subset composition of recipient and graft lymphoid compartments does not change after small bowel transplantation, even in the presence of a substantial recipient cell infiltration. The reasons for the apparent discrepancies in the degree of host cell infiltration when assessed using immunohistochemical and flow cytometric techniques are currently uncertain, but may result from the localised release of soluble MHC class I in graft tissues as a consequence of infiltrating host cell activation or localised cell destruction.

A definite age–sex–migration complex has been determined during studies on the migratory behavior of Toxocara canis Werner, 1782 in dogs. It has also been established that intrauterine infection occurs as a result of the reactivation of larvae in the somatic tissues of the bitch during gestation.