An investigation of allograft tolerance: Discordant reactivity to murine H-Y-incompatible lymphoid cell (PEC) and skin grafts.

The extremely sensitive peritoneal exudate cell (PEC) transfer technique has been applied to an investigation of the immune response of female mice which are "tolerant" of the male antigen. Females rendered tolerant of male skin grafts by multiparity, neonatal inoculation of male spleen cells, or multiple inoculations of adult females with male lymphoid cells displayed second-set reactivity to male PEC while continuing to tolerate H-Y-incompatible skin grafts. Furthermore, this discordant response to male PEC and skin was adoptively transferrable to normal females by spleen cells from multiparous donors. Females rendered tolerant by irradiation and reconstitution with male cells were unresponsive to both H-Y-incompatible skin and PEC grafts. A model is proposed using two male-specific antigens, the response to which is controlled by independent genes.     

Influence of major-histocompatibility-complex-compatible and incompatible Langerhans cells on the survival of H-Y-incompatible skin grafts in rats

BN male trunk skin grafts, the Langerhans cells (LC) of which have been replaced with major histocompatibility complex (MHC)-incompatible Lewis female cells, survive longer on BN female rats than BN male trunk skin grafts bearing BN female LC. Evidence is presented that the privilege afforded these grafts is a consequence of MHC restriction. Thus, supplanting the native LC population of BN male trunk skin grafts with MHC-compatible Lewis.1N female cells has no affect on their survival on BN female rats. Evidence is also presented that H-Y-incompatible isografts deficient in MHC-compatible LC induce tolerance of H-Y.     

Prolongation of adult skin allograft survival by cotransplantation of neonatal skin in antilymphocyte serum and donor bone marrow cell-treated mice

Adult male B6AF1 (H-2KIb/kDb/d) mice were given skin allografts from adult male C3H (H-2k) mice, with and without contralateral cotransplants. The cotransplants were of either adult or neonatal (less than 24 hr) C3H skin. In recipient mice treated peritransplantation with antilymphocyte serum and posttransplantation with an i.v. injection of donor-strain bone marrow cells, the presence of a neonatal cotransplant resulted in significantly longer survival of the adult grafts. Median survival time (MST) for adult grafts, for the group that received a neonatal cotransplant was greater than 100 days, in comparison to MSTs of 59 days and 55 days for the groups that received only single adult grafts or the adult graft with an adult cotransplant. These results suggest an active immunomodulatory contribution of neonatal tissue, and we term this phenomenon the "cotransplant effect." This prolongation of survival of the adult grafts by the neonatal cotransplants was statistically significant in animals treated with ALS and BMC, but not in recipients that were treated with ALS only (MST = 34 days, in comparison with 29 days for groups that received either a single adult graft or an adult graft with an adult cotransplant). The graft-prolonging effects of an infusion of donor BMC thus appear to potentiate the expression of the cotransplant effect. An understanding of this effect may lead to improved methods of controlling the allograft response to adult tissues in the clinical setting.     

Induction of allograft tolerance with neonatal skin

B6AF1 recipients treated with various combinations of ALS, CsA, and BMC were grafted with C3H skin from adult or neonatal donors. A survival advantage of neonatal skin compared with adult skin was clearly demonstrated in groups treated with ALS and CsA (median survival time [MST] = 89 days, neonatal skin; 50 days, adult skin), ALS and BMC, (MST = 92 days, neonatal; 64 days, adult skin), or with ALS only (MST = 55 days and 35 days, respectively). In these groups only neonatal grafts were observed to survive greater than 100 days. Also, once it was underway, rejection of the neonatal skin proceeded more slowly than that of adult skin. ALS/BMC/CsA treatment of adult skin recipients improved graft survival modestly (MST = 77 days, 20% of grafts surviving greater than 100 days). But neonatal graft survival was prolonged remarkably by the ALS/BMC/CsA treatment, with 95% of grafts surviving greater than 100 days and 84% surviving greater than 240 days. After bearing neonatal grafts for greater than 150 days, these mice were challenged with C3H adult skin grafts. The second grafts were uniformly accepted for greater than 135 additional days, but third-party grafts were rejected promptly. This specific tolerance could not be abrogated by injection of normal B6AF1 spleen cells, and rejection of the grafts by adoptively transferred sensitized cells was delayed (MST = 35 days). That the tolerance developed in response to grafting neonatal skin to ALS/BMC/CsA-treated recipients extends to adult tissue suggests that understanding of the immunoregulatory signal provided by the neonatal tissue might lead to a tolerogenic protocol for use with adult allografts.     

Cytotoxic and agglutinating H-Y antibodies in multiparous female mice.

Pregnancy in inbred mice is associated with long-term accceptance of H-Y-incompatible skin grafts (in some "rejector" strain females) and with the formation of cytotoxic and agglutinating H-Y antibodies (in females generally). Yet there is no evident correlation between the two phenomena; postpartum females of nonrejector (H-2k), intermediate rejector (H-2d), and rejector (H-2b) strains all may produce H-Y antibodies, and postpartum H-2b females bearing H-Y-incompatible male skin grafts of long-standing may or may not produce H-Y antibodies depending on the individual recipient. Thus, it remains to be seen whether the presence of H-Y antibodies, as detectable to our sperm cytotoxicity and Protein A-SRBC agglutaination tests, signifies a corresponding presence of enhancing H-Y antibodies in pregnant females, and indeed whether enhancement (with respect to H-Y antigen) may play any part in the survival of the inbred male fetus.     

Role of graft interleukin-10 expression in the tolerogenicity of neonatal skin allografts

BACKGROUND: Allografts of skin from neonatal donors survive longer than those from adult donors and can induce tolerance in mice that are treated with short-term immunosuppression. Neonatal (< or =24 hr old) epidermal cells (EPC) secrete high levels of interleukin-(IL) 10 and include abundant class II- immature Langerhans cells (LC). In this study, the role of IL-10 in the tolerogenicity of neonatal skin grafts was examined. METHODS: After a preliminary experiment established that tolerogenesis by neonatal grafts could be supported by monoclonal antilymphocyte antibodies, B10.A(5R) recipients were immunosuppressed with anti-CD4 plus anti-CD8 (days 0, +2) and adult C57B1/6 bone marrow cells (day +7). Recipients were grafted with adult or neonatal C57B1/6 skin from wild-type or IL-10 deficient ("knockout" donors). EPC from wild-type and knockout neonatal skin were compared by flow cytometry, before and after 48 hr culture, to adult cells in terms of class II and costimulatory molecule expression. RESULTS: Grafts from knockout neonates survived longer than those from adult donors (median survival, MST=81 vs. 61 days), but not as long as those from wild-type neonates (MST=100 days; P<0.05). As with normal neonatal EPC, neonatal knockout EPC expressed little class II antigen. Both types of neonatal EPC acquired class II in culture, and up-regulated CD80 and CD86 in an adult pattern, but failed to up-regulate class II antigen to the high level seen among cultured adult cells. CONCLUSIONS: The tolerogenicity of neonatal skin grafts derives in part from natural expression of IL-10 by the graft. Another possible contribution to tolerogenicity may be the inability of neonatal antigen presenting cells to up-regulate class II fully. Low expression of class II by neonatal cells is not attributable to epidermal IL-10 secretion.     

Early vascularization of syngeneic, allogeneic and xenogeneic skin grafts

The vascularization of syngeneic, allogeneic and xenogeneic skin grafts 3-4 days after grafting was studied in inbred rats by injecting hosts with 51Cr labelled red cells on the third day and counting graft radioactivity on the fourth day. Vascularization as determined by this method was quantitatively similar in syngeneic, allogeneic and mammalian xenogeneic grafts, while the vascularization of non-mammalian xenografts was significantly inferior. For any one donor-host combination, full-thickness grafts contained relatively more blood than did split-thickness grafts, presumably because of the large vessels in the deep part of the dermis in full-thickness grafts. Full-thickness neonatal grafts were vascularized similarly to full-thickness adult skin grafts. Grafted skin contained relatively more blood than did the corresponding normal skin. Reconstituted freeze dried allogeneic skin grafts contained virtually no blood, a phenomenon possibly analogous to the 'no reflow' phenomenon of microsurgery. The inferior vascularization of non-mammalian xenografts is more plausibly explained on the basis of defective self recognition than as representing a reaction to foreign determinants. These results do not necessarily indicate that one type of graft is better than another in clinical practice. But if the beneficial effects of temporary skin grafts do indeed depend on their capacity to become vascularized, fresh skin appears preferable to reconstituted freeze dried skin.     

Fetal skin allografts on newborn excisional wounds

There is clinical and experimental evidence that skin allografts improve secondary intention wound healing, however the grafts do not take. Because of the special characteristics of the healing process in the fetal period, fetal skin allografts could be presumed to be a good alternative to adult skin allografts, and even to autografts in particular cases. In order to explore the behavior of fetal skin grafts on newborn animals, skin has been grafted to laboratory rabbits of two different ages: 26 fetal skin allografts to fetuses and newborns and 21 neonatal skin allografts to newborns. Macroscopic and microscopic features of the grafted area have been compared at the 7th, 14th and 21st postoperative days. The newborn response to a fetal skin graft was somewhat different from that to a newborn skin allograft, the first showing an earlier increase in graft bed vascularization, less edema and less foreign body reaction.     

Major histocompatibility complex restriction and cross-priming of H-Y antigen in rats

Although female rats can be sensitized to H-Y-incompatible male skin isografts following exposure to MHC-incompatible male lymphoid cells, these cells are not as effective as MHC-compatible male cells. Evidence is presented that the effectiveness of the MHC-incompatible cells is a consequence of crosspriming and that such crosspriming only occurs if these cells are rejected.     

Acceptance of H-Y-disparate corneal grafts despite concomitant immunization of the recipient

Male-specific, H-Y antigen is a widely utilized antigen system for analyzing the role of non-MHC transplantation antigens in graft rejection. In this study, we examined the role of H-Y antigen in corneal graft rejection. Orthotopic corneal grafts from male LBNF1 rats were transplanted to syngeneic female LBNF1 recipients. The male corneal grafts survived beyond 100 days on naive female recipients. In other experiments, hosts bearing clear male corneal grafts and systemically immunized with subcutaneous inoculations of male splenocytes followed by full-thickness male skin grafts failed to reject their corneal grafts, even though the male skin grafts were swiftly rejected. The inability of female hosts to reject existing male corneal grafts suggested that the cornea failed to express H-Y transplantation antigen. Further experiments, however, revealed that male-specific antigen was expressed on corneal grafts. Hosts bearing clear male grafts in the left eye rejected subsequent male skin grafts and promptly rejected male corneal grafts transplanted to the contralateral eye. Interestingly, the original male corneal grafts remained clear during the rejection of both the skin graft and the second corneal graft. The results indicate that corneal grafts representing minor histocompatibility disparities enjoy immunologic privilege in the naive host, even if the host is subsequently immunized systemically.     

Prolonged adult skin allograft survival as a result of cotransplantation with neonatal tissue. The requirement for antigen sharing between graft and cotransplant.

The survival of an adult skin allograft can be prolonged by a cotransplant of neonatal, but not adult, skin on the same recipient. We demonstrated this phenomenon using a C3HeB/FeJ (H-2k; C3H) adult graft and neonatal cotransplant donors. The median survival time (MST) for adult graft survival on B6AF1 (H-2a/b) recipients was 59 days on recipients treated with antilymphocyte serum and donor bone marrow cells. With adult or neonatal cotransplants, the MSTs for adult graft survival were 55 and > 100 days, respectively. Our current experiments explore the specificity of this phenomenon by substituting neonatal cotransplants of several allogeneic and partially allogeneic strains. Cotransplants that do not share the antigens presented by the adult graft to the recipient as foreign do not produce any prolongation of adult graft survival. Thus, cotransplants of adult or neonatal C57BL/6J (H-2b) or A/J (H-2a) strain skins had no significant effect on adult C3H graft survival. In contrast to these results, neonatal (but not adult) cotransplants that share presented antigens produce a significant cotransplant effect. The presence, on a recipient, of a neonatal cotransplant of CBA/J (H-2k) resulted in significant prolongation of adult skin grafts (MST > 150 days; P < 0.05). As well, on a different recipient strain (CAF1; H-2a/d), neonatal C3H-H-2o2/SfSn (H-2o2) skin cotransplants, sharing only background antigens and H-2Dk with the adult graft donor, caused a significant prolongation of adult graft survival relative to that seen on recipients bearing only a single adult graft (MSTs = 53 and 31 days; P < 0.05). Our results suggest that this graft-prolonging effect of neonatal cotransplantation requires that the cotransplant shares antigens with the adult graft that are presented as foreign to the recipient.     

Behavior of male-specific minor histocompatibility antigen in skin and limb transplantation

BACKGROUND: Although the role of male-specific minor histocompatibility antigen H-Y has been increasingly understood in both experimental and clinical organ transplantation, little has been investigated on musculoskeletal tissue transplantation. This study was performed to describe the behavior of male-specific minor histocompatibility H-Y antigen in rat skin and whole limb transplantation. MATERIALS AND METHODS: Using three different strains of inbred rats (Lewis, F344, and Dark Agouti), 75 donor hindlimbs and eighteen skin grafts were isogenically transplanted to the sex-mismatched recipients. Recipients were observed up to 48 weeks postoperatively. Rejection was monitored by the appearance of the skin of the grafted limb and histology. Systemic microchimerism was assessed by polymerase chain reaction using Y-chromosome specific primers. RESULTS: Skin rejection didn't occur in all limb transplant recipients and histology did not show any rejection findings in all components of the limb graft through 48 weeks. Successful functional recovery was expected. Stable and high level of chimerism (>1%) was detected in the lymphoid tissues in nontreated female recipients. Male skin grafts were rejected by Lewis and F344 female recipients within 6 weeks postoperatively. All female skin grafts survived in male recipients. CONCLUSION: Our results suggest that H-Y antigen can induce graft rejection in rat skin graft but causes no rejection reaction in whole limb transplantation. Systemic chimerism may play an important role for acceptance of sex-mismatched limb graft.     

Major-histocompatibility-complex-restricted male skin graft rejection responses in rats

Normal DA (RT1a) female rats rejected male skin isografts when preimmunized with RT1-compatible DA, or ACI (RT1a) male bone marrow cells (BMC), but failed to reject them when preimmunized with RT1-incompatible PvG/c (RT1c), F344 (RT1lvl), or BN (RT1n) male BMC--as well as when they were untreated. DA female rats rendered neonatally tolerant to RT1-incompatible PvG/c female tissues failed to reject, not only DA, but also PvG/c male skin grafts when preimmunized with PvG/c male BMC. DA female rats tolerant of PvG/c female tissues that had rejected DA male skin grafts following immunization with DA male BMC failed to reject PvG/c male skin grafts. These results indicate that in rats, unlike mice, male skin graft rejection responses are MHC-restricted, at least in the DA strain.     

Contrary intermittent skin release of complete syndactyly without skin graft in adults

INTRODUCTION: There are many different surgical treatment techniques of complete syndactyly. Most of them are techniques involving using skin grafts. We developed a surgical technique that does not require skin grafts, which cause problems in the distal nail border pulp and interdigital web space. MATERIALS AND METHODS: Syndactyly release was performed in 12 web spaces of 11 adult male patients. The average age was 21. In addition to a zig-zag incision, contrary intermittent skin release was performed. Primary coverage of the interdigital web space and nail border pulp was achieved without skin graft. RESULTS: We obtained good results by the contrary intermittent skin release method that we developed, in adult complete syndactyly patients who had no chance for the surgical treatment due to several reasons, previously. CONCLUSION: With such a surgical technique, in our cases we obtained successful results, both cosmetic and functional. The presented technique is an alternative method for syndactyly release without using skin graft in adult patients.     

The role of MHC and non-MHC antigens in the rejection of intracerebral allogeneic neural grafts

Embryonic DA retinal allografts that have survived for prolonged periods after having been transplanted into the brains of neonatal BN rats can be induced to reject following peripheral sensitization with a DA skin graft. The results show that histocompatibility antigens play the major role in the rejection of grafts placed in the CNS and that a disparity between the retinal and skin grafts for MHC antigens induces a more severe rejection response than does a non-MHC antigen disparity.     

Biochemical study on the process of skin graft take.

Investigations on the process of skin graft take have been performed by many investigators and it has been shown that skin grafts become viable after revascularization from the graft bed after passing through a certain period of circulatory interruption. However, there are some disagreements between researchers regarding the role played by serum and the onset time of revascularization. We have investigated the changes in adenosine 5'-triphosphate (ATP) and glucose levels of skin grafts in rats to understand the biochemical process of skin graft take. A total of 250 male Wistar rats were used, and 450-microns split-thickness skin grafts were cut from their backs using a dermatome. In Group 1, the skin graft was grafted onto the dorsal fascia of the same rat. In Group 2, a 191-microns-thick Millipore filter with 1.5-microns pores was interposed between the graft and the dorsal fascia to inhibit revascularization. In Group 3, the skin graft was enveloped in a piece of gauze containing physiological saline solution and incubated at 37 degrees C. Skin grafts were removed at 6, 12, and 24 hours as well as on days 2, 3, 4, 5, 6, and 7 after grafting. The ATP and glucose levels were extracted from the grafts and quantitated using high-performance liquid chromatography. In Group 1, the ATP and glucose levels in the graft decreased rapidly after grafting; the ATP level fell to approximately 30% of that before grafting and glucose to about 20%, on days 2 and 3, respectively. Thereafter, these levels increased gradually.(ABSTRACT TRUNCATED AT 250 WORDS)     

Effect of thymectomy,irradiation, T cell depletion,or AgB compatibility

A series of experiments is presented which compares the survival of cardiac allografts placed in AgB-compatible rats and in AgB-incompatible animals whose immunological capacities were diminished by thymectomy, total body irradiation, or by thymectomy, irradiation, and bone marrow replacement. Cardiac allografts transplanted between rat strains differing at minor AgB loci survived indefinitely, despite immunological challenge by serial-test skin allografts or the adoptive transfer of sensitized lymphoid cells. In animals with major AgB differences, cardiac allografts were rejected acutely within 7 days. Graft survival was increased significantly in animals undergoing neonatal thymectomy, although no effect occurred with adult thymectomy. Grafts transplanted to recipients receiving sublethal doses of irradiation survived for prolonged periods before ultimate rejection, although the cardiac grafts of B rats survived indefinitely. While primary test skin grafts did not affect heart function, second grafts or the adoptive transfer of sensitized lymphocytes caused allograft destruction. Serum from irradiated animals bearing well-functioning cardiac transplants, adoptively transferred into syngeneic recipients of heart grafts, caused slight prolongation of graft survival. These studies emphasized the complexities of both cellular and humoral host responses against organ allografts.     

Effects of sex steroid hormones on sex-associated differences in the survival time of allogeneic skin grafts in rats. Evidence that testosterone enhances and estradiol reverses the immunosuppressive activity of cyclosporine

Three-week-old DA (RT1a) male and female rats were pretreated with either orchiectomy or ovariectomy and administration of the opposite-sex steroid hormones, estradiol or testosterone. Skin from same-sex AO (RT1a) rats was then grafted when these pretreated rats reached 14 weeks of age, with a short course of immunosuppressive treatment of cyclosporine. The survival times of the grafts were reversed in that the male recipients pretreated to be like females acutely rejected the graft within 10 days as do normal adult female recipients. On the other hand, the female recipients pretreated to be like males accepted the graft as do normal adult male recipients. In addition, the synergistic effects of either testosterone or estradiol with CsA on the survival time of the graft were examined. Testosterone successfully prolonged graft survival on normal adult female and young male recipients, but negligible prolongation was observed on young females. In contrast, estradiol abrogated the immunosuppressive activity of CsA and accelerated graft rejection in both male and female recipients.     

Dissociation of antigenicity and immunogenicity of neonatal epidermal allografts in the mouse

Cultured neonatal epidermal cells or sheets have been grafted successfully onto allogeneic recipients across an MHC barrier, while genetically identical skin allografts were rejected. Induction of specific allosensitization by prior priming with allogeneic spleen cells or allogeneic skin grafts did not prejudice the survival of subsequent cultured epidermal allografts. When cultured epidermis and adult skin of the same genotype were grafted simultaneously, as double grafts, cultured epidermis survived despite the presence of an ongoing allograft rejection reaction in the host. Furthermore, pretreatment of the recipients with cultured epidermis failed to protect against rejection of subsequent allogeneic adult skin grafts of the same genetic origin. These data indicate that cultured epidermis is neither immunogenic nor antigenic in allogeneic host. In companion experiments it was determined that neonatal (noncultured) epidermal allografts also survived indefinitely, implying that neonatal epidermis lacks antigenicity. However, in contrast to cultured epidermis, neonatal epidermal allografts evoked specific systemic immunity in their recipients, since they rejected a subsequent allogeneic adult skin grafts in accelerated fashion. These data demonstrate that in neonatal epidermis antigenicity can be dissociated from immunogenicity.     

受体性别及完整性对睾丸组织移植物发育的影响

目的以免疫缺陷小鼠为受体,探讨受体的性别及完整性对未成熟睾丸组织移植物生长发育的影响。方法将作为受体的免疫缺陷小鼠分为4组:雄性正常组、雄性去势组、雌性正常组和雌性去势组。移植供体组织均为新生1～2d的昆明小鼠睾丸,移植部位为受体背部皮下。移植7周后取材,计算移植物的回收率并称重,对各组移植物中生精小管结构和生精细胞的组成情况以及生精细胞的染色体进行观察分析。结果移植7周后,从4组受体中获得的移植物体积和重量与移植前相比均有明显增加。染色体观察显示,所有4组移植物中生精细胞染色体数量均为正常2倍体(40条)和单倍体(20条);HE染色结果显示,所有4组受体取出的移植物中均发现带有长形精子的生精小管,其中雄性正常组、雄性去势组、雌性正常组和雌性去势组分别有1、5、1和3只受体中观察到含有长形精子的生精小管。结论新生昆明小鼠睾丸组织分别移植到去势的、未去势的雄性和雌性免疫缺陷小鼠背部7周后,未成熟的生精细胞均可发育成为长形精子。