Analysis of allogenic lymphocytes in rat thymus following sublethal irradiation

The effects of allogeneic lymphocytes on the rat thymus following sublethal irradiation were investigated using immunofluorescence. The recovery of thymus weight following irradiation was delayed in rats 6 days after receiving lymphocytes compared to controls. Allogeneic cells forming colonies were detected by immunofluorescence in both the cortex and medulla of the host thymus, most frequently on day 15 when an appropriate number (3 x 10(6)) was injected. The allogeneic cells detected in the host thymus, presumably T lymphocytes, appeared to disturb thymic reconstitution following irradiation. However, double-immunofluorescence staining revealed that allogeneic cells did not affect the thymic stromal microenvironment. Allogeneic cells may have subsequently affected thymic tissue via cytokines. It is important to investigate not only the character of allogeneic cells in the host thymus but also the interactions of donor allogeneic cells, host immature lymphocytes and thymic epithelial cells because of the possibility that these allogeneic cells in the host thymus could prevent the rejection of allogeneic transplants.

Morphological and flow cytofluorometrical analyses of regenerated rat thymus after irradiation

Reconstituted rat thymuses were studied by immunohistochemistry, transmission electron microscopy (TEM) and flow cytofluorometry on days 0, 1, 2, 3, 5, and 7 after whole-body sublethal irradiation (6 Gy). One day after irradiation, numerous apoptotic cells were seen in the cortical thymus; the percentage of the sub-G1 peak representing apoptotic cells was 8.9% in the DNA content histogram of cytofluorometry. On day 3, the thymic structure had been destroyed and no distinction was drawn between the cortex and medulla. In this stage, few thymocytes but many macrophages were present, and the percentage of the sub-G1 peak reached a peak at 13.0%. Bromodeoxyuridine (BrdU) incorporated cells gradually increased after irradiation, and immunohistochemically numerous apoptotic cells were found primarily in the cortex on day 7. These thymocytes showed some levels of electron density of the nucleus as revealed by TEM. The percentage of S phase cells did not change markedly (20-30%) based on one-color DNA content histograms, but the percentage of early S and S phase cells was extremely high on day 7 (70%). These data indicate that a part of DNA synthetic cells may result in apoptosis. The combination of immunohistochemistry, TEM and flow cytofluorometry to analyze DNA content and BrdU incorporation proved a useful tool for investigating the reconstituted thymus.

The effect of methylprednisolone on platinum kinetics and urinary enzyme excretion following intravenous cisplatin in vivo and on the growth inhibition of LLC-PK1 cells by cisplatin in vitro

In order to evaluate the mechanism of the protective action of methylprednisolone against cisplatin-induced nephrotoxicity, platinum kinetics and urinary enzyme excretion following intravenous cisplatin, with or without methylprednisolone, were studied in vivo. The growth inhibition of LLC-PK1 cells by cisplatin in the presence or absence of methylprednisolone was studied in vitro. Rats intravenously injected with cisplatin combined with subcutaneous methylprednisolone 4 h prior to the cisplatin injection excreted more platinum in urine than rats treated with cisplatin alone. Both plasma and kidney platinum concentrations in rats injected with both cisplatin and methylprednisolone were significantly lower than those in rats given cisplatin alone at 4 h after cisplatin injection. However, there was no significant difference in urinary excretion of lactate dehydrogenase, gamma-glutamyl transpeptidase or N-acetyl-beta-D-glucosaminidase between methylprednisolone-treated rats and control rats. Methylprednisolone did not affect the inhibitory effects of cisplatin on the cell growth of LLC-PK1. These findings indicate that methylprednisolone-induced increase in urinary platinum excretion, accompanied by a decrease in plasma and kidney platinum concentrations following cisplatin injection in rats, may be one of the mechanisms responsible for the protective action of methylprednisolone.

Analysis of fetal rat liver using monoclonal antibodies

BACKGROUND

In previous studies, we developed several monoclonal antibodies (mAbs) against fetal and adult rat liver to analyze the hemopoietic microenvironment of the fetal liver during the gestational period. In this study, we have developed two new mAbs against fetal rat liver cells and have examined the characteristics at various gestational ages of fetal liver and of adult liver.

METHODS

The characteristics of these monoclonal antibodies were demonstrated by examining several tissues using immunohistochemical staining and flow cytofluorometry.

RESULTS

Monoclonal antibodies HAM10 and HAM11 were developed against fetal rat liver cells. These reacted with the cytoplasm of fetal and adult hepatocytes. HAM10 antigen expression was strong at approximately day 18 of gestation in the active period of hemopoiesis in fetal rat liver but was much lower in adult liver. HAM10 antigen expression also increased in liver after partial hepatectomy and was reduced abruptly to a normal level thereafter. HAM11 antigen expression in fetal liver was weaker than that of HAM10 antigen expression. The degree of HAM11 antigen expression increased as gestation proceeded, reaching a maximum in adult liver.

CONCLUSIONS

Both HAM10 and HAM11 antigens may play a role in the morphogenesis of hepatocytes and in the hemopoietic microenvironment for hemopoietic cells. Moreover, HAM10 antigen is may play a role in hepatocyte proliferation in the fetal liver, whereas HAM11 antigen may contribute to the maturation of fetal- to the adult-type hepatocytes.

The protective effect of methylprednisolone against cisplatin-induced nephrotoxicity in patients with urothelial tumors

BACKGROUND

Many attempts have been made to reduce the nephrotoxicity of the anticancer agent cisplatin but the number of clinically useful modalities is very limited. Our previous experiments demonstrated that in rats methylprednisolone significantly reduces the nephrotoxicity caused by cisplatin. The present clinical study was conducted to confirm the protective effects of methylprednisolone against cisplatin nephrotoxicity.

METHODS

Fourteen patients with urothelial tumors were injected with cisplatin according to the methotrexate, vinblastine, adriamycin, cisplatin (MVAC) therapy. Methylprednisolone was not administered during the first course of chemotherapy to provide a control, but was given in a dose of 2000 mg 2-3 hours before cisplatin during the second course of chemotherapy (treatment period) in each patient. Urinary excretion of N-acetyl-beta-D-glucosaminidase (NAG) and gamma-glutamyltranspeptidase (GGTP), serum creatinine, and creatinine clearance (Ccr) were determined as indicators of the nephrotoxicity of cisplatin. Results were statistically analyzed by a paired t test to compare the nephrotoxic effects of cisplatin during the first course of chemotherapy (control period) with those during the second course of chemotherapy (treatment period).

RESULTS

Methylprednisolone did not significantly inhibit the elevation in urinary enzyme excretion or serum creatinine levels following the cisplatin injection. However, the Ccr level after cisplatin infusion in the treatment period was significantly higher than that observed in the control period.

CONCLUSION

The protective effects of methylprednisolone against cisplatin nephrotoxicity were indicated in this prospective clinical study.

Influence of continuous interleukin-2 administration via the portal vein on liver regeneration following partial hepatectomy in rats

We have reported the efficacy of intraarterial-combined immunochemotherapy including interleukin-2 (IL-2) for unresectable hepatocellular carcinoma (HCC). To further test this therapy for prevention of intrahepatic recurrence after hepatectomy, the influence of IL-2 on liver regeneration was examined using mitotic index (MI) and the bromodeoxyuridine (BrdU) labeling index (LI) in 70% hepatectomized Donryu rats. In addition, gap junction appearance, which may change during liver regeneration, was analyzed using a monoclonal antibody (HAM8). Serum albumin, alanine transaminase, and total bilirubin (TB) levels were also evaluated. IL-2 (45,000 Japanese reference units [JRU]/d) or saline was administered continuously via the portal vein immediately after hepatectomy using an infusion pump. We also examined the influence of IL-2 on liver regeneration after hepatectomy with splenectomy. No difference in the weight of the liver, serum albumin, alanine transaminase, or TB was observed in any groups at 1, 2, or 4 days after hepatectomy. Neither IL-2 nor splenectomy influenced MI and BrdU LI at all three points. Gap junctions began to disappear after hepatectomy and reached a minimum on day 2 in all groups. Four days after hepatectomy, the density of the reappearing gap junctions was markedly lower in groups treated with IL-2 than in those receiving saline with or without splenectomy. However, the density returned to close to preoperative levels 6 days after hepatectomy in all groups. Continuous portal infusion of IL-2 transiently disturbed gap junction reappearance during liver regeneration. However, no other parameters of liver regeneration or liver functions differed. These results suggest that the liver regeneration after partial hepatectomy may be suppressed by the administration of IL-2, even though the suppression may not be harmful for overall recovery of the resected liver. However, it seems that hepatic IL-2 administration can be performed without serious complications after hepatectomy.

1,25-dihydroxyvitamin D3 stimulates phagocytosis but suppresses HLA-DR and CD13 antigen expression in human mononuclear phagocytes

This study investigated the regulatory activity of 1,25-dihydroxyvitamin D3 (1,25-[OH]2D3) on phagocytic cells obtained from normal human peripheral blood. Flow cytometric analysis enabled identification of two discrete populations of cells, one predominantly monocytes ("monocyte" gate) and one containing primarily lymphoid and other cell types ("lymphoid" gate). The monocyte-associated antigens CD13 and CD33 were highly expressed by cells in this monocyte gate and used to monitor this population. Following 5 days of culture, cells in the monocyte gate manifested high phagocytic activity as determined by ingestion of fluorescent carboxylmicrospheres and exhibited high expression of class II HLA-DR products. 1,25-(OH)2D3 profoundly upregulated phagocytic activity while downregulating HLA-DR antigen expression on the cells in the monocyte gate. Moreover, 1,25-(OH)2D3 also reduced cell surface CD13 expression on the cells with low but not high phagocytic activity in this gate. Proportional activities by the 1,24-(OH)2D3 and 24,25-(OH)2D3 metabolites indicated the regulatory effects are likely mediated by the 1,25-(OH)2D3 receptor (VDR). Prostaglandin E2 (PGE2), a known modulator of monocyte/macrophage activity also markedly inhibited HLA-DR expression while enhancing the phagocytic activity of cells in the monocyte gate. In contrast to 1,25-(OH)2D3, PGE2 clearly upregulated CD13 expression in cells with high phagocyte activity. Since indomethacin, an inhibitor of PGE2 synthesis, failed to reverse the 1,25-(OH)2D3 induced inhibitory effect on HLA-DR expression, this effect is apparently not mediated through endogenous PGE2 synthesis. Based on these findings we speculate that 1,25-(OH)2D3 may be capable of acting as both an upregulating agent during natural immunity via the enhancement of phagocytosis by monocyte/macrophage populations and as a "downregulator" during acquired immune responses via an inhibitory effect on MHC class II antigen expression by professional antigen-presenting cells.

Major histocompatibility complex expression in muscle of rats with graft-versus-host disease

Immunohistochemical examination of rat skeletal muscle during graft-versus-host disease (GVHD), a systemic immune reaction, was performed to investigate specific immune reactivities focusing on major histocompatibility complex (MHC) expression and inflammatory cell infiltration of skeletal muscle during a systemic immune reaction. MHC class II expression and inflammatory cell infiltration did not increase. MHC class I was expressed along the contour of muscle fibres, and most strongly expressed by the cells which were distributed throughout the endomysium and perimysium. Seventy-six percent of these MHC class I+ cells carried endothelial cell-markers, while 24% of them did not. The latter cells were revealed not to be inflammatory cells such as lymphocytes, granulocytes or macrophages when examined by immunostaining using several exudate-cell markers. Neither were they myosatellite cells because they were located outside the basement membrane. These results may be useful for considering animal models of inflammatory myopathies such as polymyositis and dermatomyositis.

Immunohistochemical localization and biological significance of the phylogenically conserved thymus-brain antigen (UB-13 antigen) in skate, rat and human

A monoclonal antibody (UB-13) originally raised against the brain of the skate (Raja kenojei, a cartilaginous-fish) was found to react with lymphoid and brain tissues from many species when examined immunohistochemically. In rat and human thymus, UB-13 antigen was observed to be closely associated with reticular tissue in the medulla and cortex. Interestingly, a few or several thymocytes were encircled by the UB-13-reactive reticular tissue. At 14 days gestation, rat thymus consisted mainly of reticular epithelial tissue, after which strong thymocyte production started. At this stage, some of the reticular tissue was heavily stained with UB-13. In the thymus tissues of the irradiated and recovering rats, where reduction and massive reproduction of thymocytes were observed, extensive UB-13 antigen expression localized on the reticular epithelial tissue, an observation which may support the thymocyte re-population. These findings suggest that the antigen recognized by UB-13 may be important for thymocyte proliferation and maturation. UB-13 antigen was found in the fibrous structure of the molecular and granular layer of the human cerebellum. Some glial cells were also stained strongly with UB-13 in the human cerebellar or cerebral grey and white matter. In rat, glial cells, especially astroglias, and the endothelial structure of blood vessels were stained strongly with UB-13. These findings suggest that UB-13 may be a useful monoclonal antibody for analysis of brain-lymphoid antigen in many species.

[Effect of growth hormone and thyroxine on renal development in Snell pituitary dwarf mice]

To elucidate the effects of growth hormone (GH) and thyroxine (T4) on renal development, we biochemically and morphologically examined the renal tissue of Snell pituitary dwarf mice (dw/dw) at different developmental stages. Differences in DNA, RNA and insulin-like growth factor-1 (IGF-1) content between the dwarf and normal control mice first became apparent on the 10th day of age, and from this time that of dwarf mice showed no further increase in DNA and RNA content and decrease in IGF-1 content, whereas that of the normal control mice continued to increase. These findings indicated that GH and T4 may have effects on the renal development, and deficiency of these hormones to affect renal development from the 10th day of age.

Analysis of cell surface antigens using anti-rat hepatocyte monoclonal antibodies, particularly HAM 1

The expression of antigens on rat hepatocytes was examined by immunoelectron microscopy using monoclonal antibody HAM 1. The antigen recognized by HAM 1 was expressed mainly on both sinusoidal and bile-canalicular faces and only sparsely on the contiguous face. All rat hepatoma cell lines examined were intensely labeled with HAM 1, but poorly labeled with HAM 3, HAM 4, and HAM 5, as revealed by flow cytofluorometry and radioimmunoassay. Expression levels of HAM 1 antigen on the AH 44 hepatoma cell line similar to the degree seen in normal liver were demonstrated by radioimmunoassay. HAM 1 antigen was also expressed weakly on lymphocytes, thymocytes, and some bone marrow cells, but not on red blood cells, and differed from the MHC class I antigen recognized by HAM 2 and OX 18. Significant amounts of cell surface antigens recognized by all the monoclonal antibodies (HAM 1-HAM 5) were confirmed by radioimmunoassay on the cell surface of primary cultured hepatocytes. These results suggest that the rat hepatoma cell lines employed are different from normal hepatocytes, that primary cultured hepatocytes are more similar to normal hepatocytes in the degree of expression of their cell surface antigens, and that HAM 1 antigen appears to be a significant antigen on both normal and transformed hepatocytes.

[Pyomyositis of iliopsoas muscle with infection of renal cyst: a case report]

We report a case of pyomyositis of iliopsoas muscle with infection of renal cyst. A 50-year-old woman was admitted to our hospital complaining of left lumbago, and we suspected that she had a left ureteral stone at first. Ultrasonogram and intravenous pyelography showed bilateral multilocular renal cyst and enlargement of the left iliopsoas muscle. Finally she was diagnosed with left pyomyositis of iliopsoas muscle with infection of renal cyst by ultrasonogram, computerized tomography scan and magnetic resonance imaging. She had no complaints after she had received antibiotic therapy for a week.

Changes in the distribution and intensity of alkaline phosphatase activity in rat lymph node and spleen cells after antigen stimulation

We investigated the reaction of the popliteal lymph nodes (PLN) to the injection of two antigens, keyhole limpet hemocyanin (KLH) and lipopolysaccharide (LPS), into the footpads of rats, as well as the changes occurring in the PLN after allogeneic cell stimulation. Changes in alkaline phosphatase (ALP) activity of the lymph nodes were examined enzyme histochemically. Paralleling with PLN weight gain, increased ALP activity was observed in the medullary regions of the lymph nodes of stimulated rats. ALP reactivity in the stimulated lymph nodes was observed to be weak in the germinal centers and strong in the medullary regions. The spleens of rats subjected to systemic graft-vs.-host (GVH) reaction were examined in a similar fashion. The ALP-positive areas of the GVH spleens increased in size as compared with normal spleens. These positive areas of lymph node and spleen appear to correspond mainly to areas containing OX12-positive cells. These results suggest that enzyme-histochemical analysis of ALP activity together with immunohistochemical analysis of lymphocyte phenotypes may be a useful method for examining lymph node and spleen reactions to soluble and cellular antigens in rats.

Immunohistochemical characterization of transplantable rat squamous cell carcinoma (FF-6) in skin and thymus

FF-6 is a transplantable squamous cell carcinoma which originally arose in the facial skin of a DA rat. It was established after maintaining the tumor in the subcutaneous tissue or peritoneal cavity of DA rats conventionally for over 30 generations. When the soybean-sized original FF-6 tumor was transplanted subcutaneously, it became an oval, hard, whitish, solitary and thumb-head-sized nodule within one month. After intraperitoneal transplantation of FF-6, it formed many nodules ranging from miliary to thumb-head size, which adhered and/or metastasized to many abdominal organs. When FF-6, cut into small pieces, was injected into the lower lip, the tumor grew bigger in situ, and metastasized to regional lymph nodes. Histologically, FF-6 was characterized as a well-differentiated squamous cell carcinoma, showing positive staining with anti-keratin, anti-laminin, anti-collagen type IV, anti-fibronectin and UB-14 antibodies. This transplantable tumor may be useful for analyzing the mechanisms of proliferation and metastasis of squamous cell carcinoma in vivo, and the host defence mechanism in rats, as well as being a suitable model of human squamous cell carcinoma.

[Prostatic carcinoma presenting as an abdominal mass: a case report]

Prostatic carcinoma presenting as an abdominal mass is a very rare disorder. A 64-year-old man was referred to our hospital with the chief complaint of a right lower abdominal mass on March 6, 1984. Physical examination revealed a firm, smooth, fixed, non-tender, pulseless fist size mass in the right lower abdomen. Rectal examination revealed an apple size, smooth and elastic firm prostate which had an induration. Needle biopsy of the prostate showed well-differentiated adenocarcinoma. At first we regarded the abdominal mass as retroperitoneal tumor unassociated with prostatic carcinoma. After preoperative irradiation (20 Gy) to the pelvis, the abdominal mass was resected and bilateral orchiectomy was performed on April 11, 1984. The mass was histologically diagnosed as a metastatic lesion from prostatic carcinoma. On the basis of these findings, we considered the mass to be due to pelvic lymph node metastasis from prostatic carcinoma. His postoperative course was uneventful. In April 1991, he is still alive without evidence of recurrence or bone metastasis.

Effects of FK506 on rat thymic epithelial cells; immunohistochemical study

The effects of FK506, a new immunosuppressive agent, on the rat thymus were investigated using the immunoperoxidase technique and flow cytofluorometry using monoclonal antibodies. Flow cytometric analysis of the thymus revealed that the proportion of cells labelled positively with OX7 (Thy-1 antigen), OX8 (CD8, T cytotoxic/suppressor cells) and W3/25 (CD4, T helper cells and macrophages) increased following treatment, with FK506, 1 mg/kg body weight for 14 days. A marked reduction of the thymic medulla following treatment was clearly demonstrated by staining with OX18 (MHC class I) and OX6 (MHC class II). Changes produced by FK506 were also observed in the cortical area of the thymus, being especially marked in the subcapsular area and around the blood vessels by staining with OX6, PKK-1 (alpha-cytokeratin), AB-1040 (type IV collagen), and AB-1220 (laminin). Eventually FK506 treatment resulted in patchy reduction of OX-6, PKK-1, AB-1040 and AB-1220 positive area in the cortex. This evidence suggests that FK506 may impair the thymic microenvironment and subsequently disturb the thymocyte maturation.

[Cavernous hemangioma of the spermatic cord: a case report]

Cavernous hemangioma of the spermatic cord is a very rare disorder. A 26-year-old man was admitted to our hospital with chief complaints of right intrascrotal mass and hematospermia on October 19, 1990. Physical examination revealed a hard, non-transilluminated mass in the right spermatic cord. The mass was resected via the groin. Pathological examination showed cavernous hemangioma. The patient's postoperative course was uneventful. This is only the fourth case of cavernous hemangioma of the spermatic cord to be reported in the literature in Japan.

1,25-Dihydroxyvitamin D3 down-regulation of HLA-DR on human peripheral blood monocytes

The regulatory activity of 1,25-dihydroxyvitamin D3 (1,25-(OH)2D3) on human leucocyte antigen (HLA)-DR (MHC class II) antigen expression in monocytes from normal human peripheral blood was examined. Using forward light and side scatter by flow cytometry most cells within the discrete monocyte area expressed high levels of HLA-DR antigens following 4-day culture in medium alone (culture-enhanced HLA-DR) and expression was further up-regulated in the presence of interferon-gamma (IFN-gamma) (IFN-gamma-enhanced HLA-DR). Treatment with 1,25-(OH)2D3 markedly inhibited both culture and IFN-gamma-enhanced HLA-DR but not HLA-ABC (MHC class I). This 1,25-(OH)2D3 inhibition was as effective as PGE2 and hydrocortisone. To ascertain if HLA-DR was specifically down-regulated on monocytes, the effect of vitamin D3 analogues in CD33+ cells was examined. Incubation of the CD33+ cells with 1,25-(OH)2D3, 24-25-(OH)2D3 and 25-OHD3 resulted in dose-dependent inhibition of culture-enhanced HLA-DR paralleling the vitamin D3-receptor affinities of these compounds. Northern analysis also demonstrated that 1,25-(OH)2D3 treatment markedly decreased both expression of culture-enhanced and IFN-gamma-enhanced HLA-DR beta chain messenger RNA (mRNA) in monocyte-enriched populations. In total, our findings are consistent with the proposal that vitamin D3 analogues can contribute to down-regulating immune responses as a consequence of inhibiting class II expression.

Phagocytosis by the murine testicular TM4 Sertoli cell line in culture

To investigate phagocytosis, an assay enabling flow cytometric analysis of single cells having internalized fluorescent carboxyl microspheres was employed. Greater than 80% of murine testicular Sertoli line (TM4) cells were found to phagocytose one or more microspheres within six hours and electron microscopy confirmed carboxyl microsphere internalization. This level was equivalent to that of a macrophage-like cell line and much greater than the levels of testicular Leydig (TM3) cells. Reducing extracellular calcium or using a calcium channel blocker profoundly inhibited phagocytosis suggesting that phagocytosis by Sertoli cells requires extracellular Ca++. Although follicular stimulating hormone, luteinizing hormone, and testosterone had no significant effects on Sertoli cell phagocytosis, insulin, epidermal growth factor, and hydrocortisone enhanced activity. In contrast, beta-endorphin and 8-bromoadenosine-cyclic monophosphate had an inhibitory effect. In contrast to augmenting macrophage phagocytosis, 1,25-(OH)2D3, interferon-gamma, prostaglandin E2, and lipopolysaccharides, had no apparent effect on that by Sertoli cells. Additionally, neither C3bi receptors (Mac-1 antigen) nor FcRII could be detected on Sertoli cells. In total, the findings demonstrated that the murine Sertoli line exhibits potent phagocytic function and suggest the regulation of this activity may differ from that in "professional" phagocytic cells.

[Clinical evaluation of intramuscular imipenem/cilastatin sodium in surgical infections]

A multi-center clinical study was carried out at the first Department of Surgery, Okayama University Medical School and its affiliated institutions to evaluate the efficacy and safety profiles of intramuscular imipenem/cilastatin sodium (IPM/CS) in surgical infections, which were mainly biliary tract infections and peritonitis. The following results were obtained: 1. The efficacy rate was 72.0% in a total of 25 evaluable patients and 81.8% in patients with cholecystitis. 2. The efficacy rates in patients with and without underlying diseases were 70.0% and 73.3%, respectively, and they were 71.4% in patients with mild or moderate infections and 75.0% in patients with severe infections. 3. Bacteriologically, the eradication rate was 100% for Gram-positive bacteria and 62.5% for Gram-negative bacteria, with an overall eradication rate of 78.6%. The eradication rate for monomicrobial infections was 71.4% and that for polymicrobial infections was 100%. 4. Out of 25 patients, one developed diarrhea as a drug-related adverse reaction, and laboratory abnormalities attributable to the treatment were observed in 5 patients. None of them was serious, however. 5. The overall usefulness rate was 60.0%, and the usefulness for cholecystitis (72.7%) was superior to that for cholangitis (33.3%).

Interferon-gamma induces the expression of major histocompatibility antigens by human retinal glial cells

Retinal glial cells normally do not express major histocompatibility (MHC) molecules. However, the expression of MHC antigens by retinal glial cells under certain pathological conditions suggests that these cells may play a role in immune responses of the retina. At present, the identity of molecules that may regulate the expression of class I and class II MHC antigens by retinal glial cells has not been established. Since interferon-gamma (IFN-gamma) induces MHC antigens in a variety of cell types, we examined the effect of this lymphocyte product on class I and class II antigen expression by human retinal glial cells in culture. Glial cells derived from post-mortem donor eyes were exposed to recombinant human IFN-gamma. Cells with MHC class I or class II antigens were detected with the use of specific monoclonal antibodies that were labeled directly or indirectly with fluorescent probes. Fluorescence of labeled cells was assayed by flow cytometry. Exposure to IFN-gamma increased the expression of class I and class II antigens by the retinal glial cells. Double labeling studies showed that 90% of the glial cells induced to express class II antigens also had class I antigens. Overall, the results show that IFN-gamma can regulate the expression of MHC molecules by human retina glial cells in culture. These findings are consistent with the concept that glia may play a role in immunological disorders affecting the retina.

1,25-Dihydroxyvitamin D3 antagonizes interferon-gamma-induced expression of class II major histocompatibility antigens on thyroid follicular and testicular Leydig cells

Interferon-gamma (IFN gamma) induces production and expression of major histocompatibility complex class II molecules on both marrow-derived and nonbone marrow-derived cell types. 1,25-Dihydroxyvitamin D3 [1,25-(OH)2D3], a seco-steroid derived from vitamin D3, has previously been reported to enhance such expression alone or together with IFN gamma on a number of monocyte/macrophage tumorigenic lines. In contrast, the present studies have found that 1,25-(OH)2D3 inhibited the ability of IFN gamma to induce class II antigen expression on nontransformed rat thyroid follicular epithelial cells (FRTL-5) and mouse testicular Leydig cells (TM3). Although 1,25-(OH)2D3 inhibited the induction of both IA and IE class II locus products, IFN gamma augmentation of class I major histocompatibility complex antigens was not affected. 1,24-(OH)2D3 and 24,25-(OH)2D3 also inhibited class II induction by IFN gamma. Notably, the relative inhibitory ability of these compounds paralleled the strength of their binding affinities for the 1,25-(OH)2D3 receptor, indicating that this antagonistic effect probably requires receptor-ligand interaction. Other steroid hormones, such as hydrocortisone or testosterone, had no inhibitory effect on IFN gamma-induced class II expression on Leydig cells. Additionally, the failure of indomethacin to reverse the effect of 1,25-(OH)2D3 and the finding that exogenous prostaglandin E2 did not inhibit class II induction in these cells indicated that prostaglandins are probably not responsible for this anti-IFN gamma activity. In total, these results suggest that an endocrinological mediator is capable of inhibiting class II induction on resident endocrine tissue populations and, therefore, could help to diminish local CD4+ T-cell recognition of these cells.

Differential regulation and expression of major histocompatibility complex (MHC) and Ly-6 gene products on mouse testicular Leydig and Sertoli cell lines

The expression and regulation of Class I and Class II major histocompatibility complex (MHC) and Ly-6 antigens were examined in BALB/c testicular cells. Studies were performed utilizing differentiated murine Leydig (TM3) and Sertoli (TM4) cell lines. Neither Class I (Dd) nor Class II (IA/Ed) MHC antigens were detectable on untreated TM3 cells. However, concanavalin-A activated spleen cell supernatant (Con-A sup) or interferon-gamma (IFN-gamma) treatment resulted in the marked induction of both Class I and Class II MHC antigens on virtually all of the Leydig cells. MHC Class II mRNA, which was not detected in resting cells, was clearly induced following IFN-gamma incubation. Sertoli cells were found to constitutively express low levels of Class I (Dd) but not Class II (IA/Ed) antigens. However, in contrast to the enhanced MHC expression in TM3 cells, Con-A sup or IFN-gamma treatment of TM4 cells resulted in marked augmentation of Class I, but not Class II, MHC antigens. Northern blot analysis failed to detect Class II mRNA in either the resting or IFN-gamma treated TM4 populations. Neither ethanol nor tumor necrosis factor (TNF) alone, or together with IFN-gamma head significant effects on MHC expression by TM3 and TM4 cells. Ly-6 antigens, predominantly expressed on hematopoietic cells, were found to be present on both TM3 and TM4 cells. Expression of this non-MHC encoded product was also shown to be markedly enhanced by IFN-gamma treatment on both testicular cell lines. In total, these findings demonstrated that cytokines can differentially affect discrete cell populations arising from a particular tissue with respect to the un-regulation of MHC and non-MHC gene products. These findings are discussed in the context of autoimmune responses directed against this tissue.

Precocious puberty in a seven-year-old boy due to human chorionic gonadotropin producing pineal tumor detected by nuclear magnetic resonance computed tomographic scanning

We report a 7-year-old boy who developed incomplete sexual precocity due to a human chorionic gonadotropin (HCG)-producing tumor in the pineal region. The patient presented enlarged testes (3 x 2 x 2 cm) bilaterally, enlarged penis, pubic hair development of Tanner Stage III, advanced bone age and growth spurt. Initial hormonal studies showed an adult male level of testosterone (13 ng/ml) and a high level of HCG as well as HCG-beta subunit. A high basal level of LH, probably due to immuno-cross-reactivity with HCG, and low basal level of FSH, probably suppressed by testosterone, did not respond to LH-RH infusion. Search for the site of HCG production failed at the initial workup, but calcification without definite signs of tumor in the pineal region was found by conventional brain CT scan. Because of subsequent progression of clinical and laboratory findings of sexual precocity, nuclear magnetic resonance computed tomographic (NMR-CT) scan was performed, which confirmed the presence of a pineal tumor three months later. The patient was treated with 4,500 rad. of radiation therapy, and responded dramatically to this regimen. He has been followed for more than two years without any signs of recurrence. We have reported here a very rare case of incomplete sexual precocity due to an HCG-producing intracranial tumor in the pineal region. An NMR-CT scan is a very useful tool for the diagnosis of some types of pineal tumor, such as germinoma, which are highly radiosensitive.

[Clinical experience of tapered distal ileum for construction of a continent colonic urinary reservoir]

Construction of continent colonic urinary reservoir was performed in 44 patients after exenteration for invasive bladder carcinoma or various gynecologic tumors. The distal ileum was tapered over a 14 French red rubber catheter. The ileocecal valve was reinforced with three circumferential silk sutures in a purse-string fashion. Full continence was obtained in all patients (100%). A non-tunneled, non-refluxing ureterocolonic anastomosis was performed in all 88 ureters. No obstruction or reflux was observed in 84 ureters (95%). There were 7 early postoperative complications and 3 of them required reoperation (pelvic abscess 1, urinary leak from ureterocolonic anastomosis 1, pouch-vaginal fistula 1). Moreover, there were 7 late complications and 3 of them required reoperation (stomal stenosis 1, parastomal hernia 2). These results suggest that this method is a safe, simple and useful one for permanent urinary diversion.

The effect of T cell depletion from spleen cell allografts on graft-versus-host disease and long-term immune reconstitution in H-2 haplotype-identical murine combinations

Graft-versus-host disease (GVHD) and states of immune reconstitution in allogeneic chimera mice across minor histocompatibility antigens were analyzed in excess of 9 months after injecting AKR/JSea (AKR) spleen cells into irradiated C3H/HeSlc (C3H) mice. When T cell-depleted AKR spleen cells were used as inoculum cells, neither graft failure nor GVHD was seen for 9 months postgrafting in the C3H mice irradiated with 660 rad or more. In an AKR - C3H (850 rad) model, Thy1.1+ or L3T4+ T cell depletion from donor AKR spleen cells abolished both acute and chronic GVHD in lethally irradiated C3H mice. Lyt2+ T cell depletion, however, resulted in acute and chronic GVHD in more than half of the recipient C3H mice. Moreover, actual existence of donor (AKR)-type T cells with L3T4 phenotype, but not Lyt2 phenotype, was always observed in the spleen of the C3H mice suffering from acute GVHD. In addition, the C3H mice that were irradiated with 850 rad, grafted with AKR spleen cells depleted of Lyt2.1+ T cells, escaped from acute GVHD and survived for more than 10 mo postgrafting, showed impaired activities of immune responses such as delayed footpad reaction to sheep red blood cells, antibody production tested by IgM plaque forming cells and reactivity to an intracellular bacterium. Listeria monocytogenes as compared with the C3H mice reconstituted with syngeneic C3H spleen cells or Thy1.1+ or L3T4+ T cell-depleted AKR spleen cells. These results suggest that L3T4+ T cells, rather than Lyt2+ T cells, contained in the grafted cells not only cause acute GVHD but also a long-term immunodeficient state (chronic GVHD) in recipient mice in the H-2-identical murine combinations examined here.

Rat thyroid epithelial cells provide limited accessory function but fail to present allo antigens in vitro

Human and mouse thyroid epithelial cells (TEC) have been reported to exhibit a number of immunological activities including partial, but not total, antigen presenting capability. In the studies described here, the thyroid stimulating hormone-dependent rat thyroid epithelial cell line FRTL-5 was tested for its abilities to provide accessory and antigen presenting cell (APC) activity. FRTL-5 cells alone were not able to function as accessory cells for ConA induced polyclonal proliferation of purified T-cells and were not capable of inducing alloreactive T-cell proliferation in mixed lymphocyte reaction (MLR) cultures. Furthermore, even following the induction and enhanced expression of MHC class II and class I MHC products, respectively by IFN-gamma, FRTL-5, cells could not function as accessory cells or induce alloreactive T-cell proliferation as the singular stimulatory population in MLR cultures. However, these epithelial cells could effectively synergize with either low numbers of spleen cells, or with supernatants from activated T-cells, to provide accessory function in ConA stimulated cultures. These findings suggest that hormone-dependent and functional rat TEC cannot directly activate resting syngeneic or unprimed allogeneic T-cells, although they can provide at least one accessory cell signal involved in T-cell activation by mitogen. Thus, the results presented here do not support contentions that such a nonhemopoietic resident cell population is capable of directly triggering the initial activation of anti-thyroid specific T-cells.

The nature of tolerance in adult recipient mice made tolerant of alloantigens with supralethal irradiation followed by syngeneic bone marrow cell transplantation plus injection of F1 spleen cells

The length of time after syngeneic bone marrow reconstitution when tolerance to alloantigens can be induced in adult mice during T cell differentiation from bone marrow cells was studied by exposing those T cells to (recipient x donor)F1 spleen cells. Supralethally irradiated C3H/He Slc(C3H; H-2k) mice were reconstituted with 1 x 10(7) syngeneic T cell-depleted bone marrow cells and then injected intravenously with 5 x 10(7) (C3H x C57BL/6[B6])F1 (B6C3F1; H-2bxk) or (C3H x AKR/J[AKR])F1 (AKC3F1; H-2kxk) spleen cells at various intervals. In the fully allogeneic combination of B6C3F1----C3H, EL-4 tumor originating from B6 was accepted, and survival of grafted B6 skin was significantly prolonged in the tolerant C3H mice treated with irradiation on day -1 followed by injection of syngeneic bone marrow cells on day 0 plus B6C3F1 spleen cells on days 0, 5, or 10, in a tolerogen-specific manner. In the multiminor histocompatibility antigen-disparate combination of AKC3F1----C3H, AKR skin grafts were permanently accepted in the tolerant C3H mice treated with AKC3F1 spleen cells on days 0, 5, 10, or 15. Immunological parameters, including cytotoxic T lymphocyte activity and delayed foot-pad reaction (DFR), were almost completely suppressed in C3H mice made tolerant of B6 or AKR antigens. A chimeric assay using a direct immunofluorescence method revealed that the tolerant C3H mice given B6C3F1 spleen cells on day 0 were mixed-chimeric for at least 8 weeks after syngeneic bone marrow reconstitution, but not definitely chimeric thereafter. The C3H mice given AKC3F1 spleen cells on day 0 were chimeric even 43 weeks after syngeneic bone marrow reconstitution, but the C3H mice given AKC3F1 spleen cells on day 15 showed temporal chimerism that disappeared within 43 weeks. The untolerant mice were never detectably chimeric. These data suggest that the earlier the timing of the injection of F1 spleen cells after syngeneic bone marrow reconstitution was, the more profound tolerance was induced. Moreover, the stronger the antigenic disparity between donor and recipient, the earlier the injection of F1 spleen cells was required to induce tolerance.

Establishment of a novel method to induce tolerance in adult mice across fully allogeneic (entire H-2 plus multiminor histocompatibility) antigen barriers, using supralethal irradiation followed by injection of syngeneic bone marrow cells plus (donor X recipient) F1 spleen cells

A novel method was established which can regularly induce profound tolerance in mice across entire H-2 plus multiminor histocompatibility (H) antigen (fully allogeneic) barriers. When recipient AKR/J Sea (AKR; H-2k) or C3H/He Slc (C3H; H-2k) mice were irradiated with 900 rad followed 1 day later by injection of 1 X 10(7) T cell-depleted syngeneic bone marrow cells plus 5 X 10(7) viable, but not mitomycin C-treated, [C57BL/6 Slc(B6) X AKR (or C3H)] F1 spleen cells via intravenous (i.v.) route, a specific tolerant state was induced against B6 (H-2b) antigens. In the tolerant C3H mice, the EL-4 tumor, which originates from B6, was accepted in a tolerogen-specific manner. Moreover, B6 skin grafts were permanently accepted in most of the tolerized AKR and C3H mice. Immunological parameters, including cytotoxic T lymphocyte (CTL) activity and the mixed lymphocyte reaction (MLR), were almost completely suppressed in the tolerant mice. An assay for chimerism using a direct immunofluorescence method revealed that the tolerant AKR mice were chimeric for the first 5 weeks after tolerance induction but not definitely chimeric thereafter. In the tolerant AKR mice, strong suppressor cells were not detected. This method could be used in order to investigate mechanisms of tolerance to allogeneic antigens in future experiments.

Drug-induced in vitro tolerance to allogeneic antigens. II. Further analysis of in vitro-tolerized spleen cells in a fully allogeneic murine combination

C3H/HeSlc (C3H, H-2k) spleen cells were made tolerant in vitro to C57BL/6CrSlc (B6, H-2b) at the cell-mediated cytotoxicity (CMC) level by in vitro stimulation for 48 hr with mitomycin C (MMC)-treated B6 spleen cells, and treatment with 5 micrograms/ml of 5-fluorouracil for a further 9 hr. These cells were given intraperitoneally to neonate (C3HxB6) F1 mice to examine whether these tolerized spleen cells would cause lethal graft-versus-host disease (GVHD). Despite the lack of CMC, the tolerized C3H spleen cells caused lethal GVHD in most of the neonate F1 mice. Evaluating from various immune parameters, it was evident that T cell populations responsible for IL-2 production, cytostasis, and delayed footpad reaction (DFR) were retained intact after in vitro tolerance induction, probably because of their less-proliferative characteristics in response to fully allogeneic antigen stimulation, and were considered to be responsible for lethal GVHD. Contribution of natural killer (NK) cells to lethal GVHD was not ruled out.

[An immunohistochemical study using a double staining method for regional lymph nodes in gastric cancer]

We have performed a double immunofluorescent staining of two monoclonal antibodies, obtained from gastric cancer patients, that were directed against lymphocyte surface antigens on the regional lymph nodes. Through this method we were able to identify the lymphoid cell subset in detail. As a result of our double staining, most OKT8+ lymphocytes were also found to be Leu 15- lymphocytes and these OKT8+ Leu 15- lymphocytes were regarded as being cytotoxic effector cells or precursors. A few OKT8+ Leu 15+ lymphocytes (suppressor T lymphocytes) were obtained. More Leu 3a+ Leu 8- lymphocytes (helper T lymphocytes) were observed than Leu 3a+ Leu 8- lymphocytes (suppressor inducer T lymphocytes). To investigate whether these T lymphocytes were activated, we used an OKT 9 monoclonal antibody directed against the transferrin receptor and an OKIa1 monoclonal antibody directed against the HLA-DR framework. Such double stained lymphocytes (activated T lymphocytes) were few.

Drug-induced tolerance to allografts in mice. XII. The relationships between tolerance, chimerism, and graft-versus-host disease

When AKR/J Sea (AKR, H-2k) mice were primed i.v. with 1 X 10(8) viable spleen cells from naive C3H/He Slc (C3H, H-2k) mice and treated i.p. with 200 mg/kg cyclophosphamide (CP) 2 days later, a minimal degree of mixed chimerism associated with tolerance to C3H skin was established without graft-versus-host disease (GVHD) and maintained for at least one month. When AKR mice were primed i.v. with 1 X 10(8) viable spleen cells from C3H mice preimmunized i.v. 7 days earlier with 5 X 10(7) viable AKR spleen cells, and treated with 200 mg/kg CP, chimerism became exclusive, but lethal GVHD occurred in the AKR mice. Moreover, most of normal AKR mice primed with the preimmunized C3H spleen cells without CP died of GVHD. In contrast, in a major histocompatibility complex (MHC)-incompatible combination of AKR (H-2k)-C57BL/6 Cr Slc (B6, H-2b), mixed chimerism, tolerance to skin allografts, and GVHD were not observed, whether or not the mice had been treated with naive or preimmunized B6 spleen cells with or without CP.

Analysis of tissue lymphocytes by double fluorescent staining--gastric cancer tissue and regional lymph nodes

An immunohistochemical study was performed on human lymphocytes in the tissue of gastric cancer, and also in the regional lymph nodes, by double fluorescent staining, using monoclonal antibodies. Leu3a+8+ cells (inducer T cells) which consist about 30 per cent of Leu 3a+ cells were seen in the tissue surrounding the gastric cancer. The other 70 per cent of Leu 3a+ cells were Leu3a+8- cells (helper T cells). In the lymph nodes they were noted in T cell areas in almost the same proportions, while in germinal centers, only Leu3a+8- cells were found. On the other hand, OKT8+Leu15- cells (cytotoxic T cells) were noted in a large number, while OKT8+Leu15+ cells (suppressor T cells) were few. Further, an increase of OKT8+Leu15- cells was seen around gastric cancer or metastatic cancer in lymph nodes. These immunohistochemical findings suggest that cytotoxic T cells are the main component in the tissue of gastric cancers and the regional lymph nodes. Increases in inducer T cells and helper T cells are probably required to induce cytotoxic T cells around the cancer tissue.

Drug-induced tolerance to allografts in mice. X. Augmentation of split tolerance in murine combinations disparate at both H-2 and non-H-2 antigens by the use of spleen cells from donors preimmunized with recipient antigens

In a fully allogeneic murine combination of C3H/HeSlc (C3H) (H-2k) and C57BL/6CrSlc (B6) (H-2b), C3H mice were primed i.v. with 1 X 10(8) spleen cells from B6 mice preimmunized i.v. with 5 X 10(7) C3H spleen cells and then were given i.p. 200 mg/kg cyclophosphamide (CP) 2 days later (Im-B6-Sc plus CP group). The tolerant state in those recipient mice was compared with that in mice made tolerant conventionally with 1 X 10(8) naive B6 spleen cells plus 200 mg/kg CP (naive-B6-Sc plus CP group). B6 skin was rejected in an almost normal fashion in both the naive-B6-Sc plus CP group and the Im-B6-Sc plus CP group. However, EL4 tumor allografts (B6 origin) inoculated after complete rejection of B6 skin grafts were specifically accepted in both groups. Moreover, the tumor growth in the Im-B6-Sc plus CP group was faster than that in the naive-B6-Sc plus CP group. Mixed lymphocyte reaction, cytotoxic T lymphocyte activity, and antibody production against the tolerogen were depressed more profoundly in the Im-B6-Sc plus CP group than in the naive-B6-Sc plus CP group. These observations were consistent with the results from tumor allografting. The other immunological parameters examined in the present study, including helper T cell activity and delayed foot-pad reaction, were retained in the Im-B6-Sc plus CP group at the same levels as in the naive-B6-Sc plus CP group. These observations were consistent with the results from skin allografting. In conclusion, tumor allograft tolerance was made more profound by the use of spleen cells from donors preimmunized with recipient antigens as the tolerogen than by the use of naive spleen cells. However, skin allograft tolerance was not achieved at all by these same treatments. The contribution of graft-versus-host disease to this phenomenon was excluded by the chimeric analysis in AKR/JSea (H-2k) mice given the preimmunized (with AKR antigens) B6 spleen cells plus CP. These results strongly support the existence of a less proliferative lymphocyte population which does not evoke cell divisions to mature even after the strong stimulation with the preimmunized spleen cells and is resistant to tolerance induction.

Drug-induced tolerance to allografts in mice. IX. Establishment of complete chimerism by allogeneic spleen cell transplantation from donors made tolerant to H-2-identical recipients

Graft-versus-host reaction (GVH) after allogeneic spleen cell transplantation was completely suppressed in an H-2-matched murine combination (AKR/J Sea [H-2k]----lethally irradiated C3H/He Slc [H-2k]) by pretreatment of the donors with recipient spleen cell antigen plus cyclophosphamide (CP). Irradiated recipients receiving cells became chimeric. In contrast to the H-2 matched combination, lethal GVH reaction could not be prevented in an H-2-mismatched fully allogeneic combination (C57BL/6 Cr Slc [H-2b]----lethally irradiated C3H/He Slc [H-2k]) by pretreatment of the donors. The results suggest that the effectors responsible for the GVH reaction were abrogated by pretreatment of the donors with allogeneic recipient spleen cells plus CP in the H-2-matched combination, but donor pretreatment failed to abrogate GVH reaction in the H-2-mismatched combination.

Drug-induced in vitro tolerance to allogeneic antigens. I. Establishment of a tolerance induction system in a fully allogeneic murine combination

C3H/HeSlc (H-2k) spleen cells were cultured with mitomycin C (MMC)-treated C57BL/6CrSlc (H-2b) spleen cells for 2 days and incubated with 5-fluorouracil (5-FU) for a further 9 hr. Thereafter, those C3H/He spleen cells were recultured with the same allogeneic cells for 5 days. Cell-mediated cytotoxicity (CMC) and mixed lymphocyte reaction (MLR) were profoundly suppressed, antigen-specifically, in such C3H/He spleen cells. In contrast, interleukin 2(IL-2) production was not impaired in the restimulating mixed lymphocyte culture (MLC) with C57BL/6. Moreover, an adequate amount of exogenous IL-2 added to the restimulating MLC did not lead to a restoration of the depressed CMC. Suppressor cell activity in the CMC assay was not detected in the C3H/He spleen cells exposed to such a tolerance induction. These results suggest that the unresponsiveness to alloantigens in CMC and MLR was induced through a clonal deletion mechanism, and there may exist a 5-FU-resistant--thus less-proliferative--cell population that can produce IL-2 even after the tolerance induction.

Different characteristics of allogeneic and trinitrophenyl-modified H-2-restricted cell-mediated lympholysis: analysis of differences in interleukin-2 dependency using an ontogenical approach

Ontogenical development of in vitro allogeneic cell-mediated lympholysis (CML) and in vitro trinitrophenyl (TNP)-modified CML was studied mainly in correlation with helper cell activity, using C3H/HeN and C57BL/6 mice. Allogeneic and TNP-modified CML were not detected in the spleen of these mice at 1 week after birth. Allogeneic CML was detectable, in parallel with increases in age. This activity in 5-week-old mice was much the same as in the 8-week-old mice but the TNP-modified CML did not appear until 8 weeks after birth. Exogenous interleukin-2 (IL-2) induced sufficient activity of TNP-modified CML, even in spleen cells from 1-week-old mice, while the same treatment had a weak but significant effect on the induction of allogeneic CML in these same cells. Experiments on the mixed lymphocyte reaction (MLR) in the presence of exogenous IL-2 showed that lymphocyte proliferation in response to TNP-modified cells was higher than that in response to allogeneic cells. These results suggest different dependencies on IL-2 between allogeneic and TNP-modified killer precursor cells. Endogenous IL-2 production and proliferative response in MLR showed that helper cells contributing to the TNP-modified CML matured later, compared to allogeneic CML. Different sensitivities to IL-2 in two types of CML, in addition to different ontogenical developments, suggest that cytotoxic T lymphocytes to allogeneic cells differ quantitatively and qualitatively from TNP-modified H-2-restricted killer cells.

Allograft rejection and immune responses against allogeneic antigens in neonatally thymectomized mice

Skin allograft survival and immune responses against allogeneic antigens homologous to skin grafts were observed in BALB/c Cr Slc (BALB) mice (H-2d) thymectomized at 1 day after birth and grafted with skin from major histocompatibility complex (MHC)-incompatible, fully allogeneic C3H/HeN (C3H) (H-2k) or MHC-compatible allogeneic DBA/2 Cr Slc (DBA) mice (H-2d), at 14 weeks of age. In neonatally thymectomized (NTx) BALB mice, survival of C3H skin grafts was not prolonged at all, but survival of DBA skin grafts was prolonged significantly, although the survival periods of DBA skin grafts were very different among individual recipients. In NTx recipients grafted with C3H skin, delayed foot-pad reaction (DFR) was not reduced, but cytotoxic lymphocyte (CTL) activity and cytotoxic antibody (CTAb) production were appreciably depressed. CTL and CTAb were reduced profoundly and consistently in all NTx mice grafted with DBA skin, while DFR was reduced to various degrees in each. The degrees of depression of DFR in these NTx mice correlated well with the prolongation of DBA skin survival, although the sample number was small. The rejection of skin allografts appears to be attributable largely to a T cell subset, the function of which can be expressed as DFR. Thymus dependency in the ontogenic development is low as compared with other T cell subsets.