Akiyoshi Sakai

Stimulation of allogeneic lymphocytes by skin epidermal cells in the rat.

SUMMARY The ability of skin epidermal cells to induce allogeneic lymphocytes into proliferation was examined in mixed skin celllymphocyte culture reaction (MSLR). The stimulating capacity of skin cells was reduced significantly by trypsin digestion, although the damage was repaired by incubation at 37 C for 3 hr. The optimal concentration of mitomycin C for treatment of stimulating cells in the MSLR differed from that in mixed lymphocyte culture reaction (MLR). Irradiation rendered them three to four times more stimulatory than did mitomycin C. Removal of adherent cells from responding cells by passage through a nylon-wool column gave a substantial elevation of the MSLR. The lymphocytes cocultured with skin cells in the primary MSLR incorporated 3H-thymidine, with the peak at the 6th day of culture. If the lymphocytes primed in the MSLR were restimulated with skin cells from the same stimulating strain, the primed lymphocytes responded promptly and in great magnitude.

En bloc transplantation of the liver, pancreas, duodenum, spleen, and kidney in the rat.

Five organs consisting of the liver, pancreas, duodenum, spleen, and kidney from (Lewis × Brown Norway)F1 rats were transplanted simultaneously as an en bloc graft to Lewis recipients. No immunosuppression was given postoperatively. Serial laporatomies were performed for macroscopic examination and biopsies of the grafts. Macroscopically, the first evidence of rejection was splenic enlargement followed by fatty metamorphotic change of the liver, dilation and loss of peristalsis of the duodenum, and injection of the pancreas. The kidney maintained normal color and consistency until late in the rejection process. Histological examination suggested that the liver and the spleen may be more vulnerable to immune attack, since in these organs cellular infiltration started earlier and was more extensive in comparison to other organs. While the pancreas exhibited a typical, although somewhat delayed rejection pattern, the kidney seemed to maintain a well preserved structure. Interestingly, the duodenum showed no significant cellular infiltration throughout the postoperative period of examination despite severe mucosal destruction.

Liver and immune responses. V: Regenerating liver cells activate syngeneic lymphocytes.

Abstract The ability of regenerating liver cells to stimulate in vitro DNA synthetic response of syngeneic lymphocytes was studied in the rat. Lymphocytes were cultured with mitomycin-C treated liver cells prepared from rats, after partial hepatectomy (HEP) and [3H]thymidine uptake assayed. Lymphocyte stimulation was observed with liver cells removed 2 days after HEP; it was highest with cells of rats 6 days after HEP and declined thereafter. For a positive reaction, a cell-to-cell contact was needed. Specific secondary response and morphological appearance suggested an immunological nature of the reaction. Lymphocyte stimulating differentiation antigens may be involved in the process of hepatic regeneration.

Dissociation of humoral and cellular immune reactions of the rabbit, guinea pig, and dog kidney xenografts in the rat

Little is yet known as to mechanisms which bring about graft rejection, either allogeneic or xenogeneic. Several investigators have reported “hyperacute” rejection in human renal allografts performed between ABO-incompatible and even ABO-compatible pairs [3, 13, 16, 22, 34, 351. A Shwartzman reaction [34] or Arthus-like phenomenon [36] was suggested to be the possible mechanism of this severe reaction. On the other hand, more interest has emerged in the study of heterografting in view of its clinical use and experimental interest. Experiences with kidney grafts between widely disparate species have given evidence in favor of circulating humoral antibodies [lo], though their nature has not been clarified yet. In closely related species, however, the rejection seemed to be, to a large extent, a cell-mediated process [l 1,261. In order to understand the interaction between humoral antibodies and cellmediated processes in xenograft reactions, an experimental model was studied of rabbit, guinea pig, and dog kidney transplants in the rat. With this model, an attempt was made to dissociate the humoral and cellular reactions by anticoagulant treatment.

LIVER AND IMMUNE RESPONSES: IV. CHARACTERISTICS OF THE LIVER CELL-LYMPHOCYTE INTERACTION

SUMMARY Rat liver cells prepared by collagenase treatment and separated by density gradient centrifugation with Ficoll-Hypaque solution (specific gravity 1.120), containing only hepatocytes (80%) and Kupffer cells (20%), were found to stimulate strongly Ag-B-incompatible lymphocytes without 2-mercapto-ethanol in culture. The same liver cells could also stimulate Ag-B-compatible lymphocytes in the presence of 2-mercapto-ethanol. A positive response was only seen when the liver cell numbers were 1 ∼ 2% of the responding lymphocytes. Viable liver cells inhibited the reaction in a two-way culture.

Minimum Length Of Time Required For Alloantigen Recognition

SUMMARY The minimum length of time required for lymph node lymphocytes to recognize alloantigens in vitro was examined in mixed skin cell-lymphocyte culture reactions. Responding lymphocytes in the mixture were successfully separated from stimulating skin cells by Ficoll-Hypaque gradient sedimentation. Lymphocyte activation by allogeneic skin cells took place within 15 min of contact. The amount of measured stimulation was approximately 30% of that produced by an equal concentration of antigen present continuously in culture. The presence of alloantigen was no longer needed after 24 hr. Several control experiments were made in order to exclude the effects of contamination and culture conditions. Identical results were obtained with allogeneic hepatocytes. These data indicate that the recognition of alloantigen leading to lymphocyte proliferation may occur during the early period of contact.

Differential survivals of F1 hybrid allografts in parental recipients.

SUMMARY Differential survival times of various organ allografts in the rat across the same histocompatibility barrier were studied by transplanting the kidney, heart, intestine, pancreas, and skin from (BN ± Le)F1 hybrid donors to Lewis recipients. Some (one-third) of the kidney grafted rats survived for a prolonged period of time (32–72 days, plus one rat surviving over 9 months), whereas all other organs and skin were promptly rejected between 7 and 21 days. Possible factors responsible for the prolonged kidney survival are discussed; the reason for this was not clear but was not related to the period of operative ischemia or postoperative blood-urea-nitrogen, nor were animals tolerant to donor antigen as evidenced by the popliteal lymph node weight assay and signs of mild rejection on histology of grafted kidneys. A hypothesis of autoenhancing mechanism is presented.

Clinical study of second kidney transplantation.

During the period from November 1972 to February 1975, 39 patients received second renal grafts in our institution. The clinical course of the patients was analyzed and compared with 121 patients who received only one graft during the same period. The graft survival either from living related or cadaveric sources was inferior in the second graft group. However, mortality was not increased by re-transplantation. Major differences were noted in the occurrence of hyperacute or accelerated type rejections. There was a high incidence of this type of rejection in the second graft group, especially in the simultaneous retransplant group.