Gamma delta TCR+ hybridomas derived from mice preimmunized via the portal vein adoptively transfer increased skin allograft survival in vivo

C57BL/6 mice receiving pretransplant immunization with C3H.SW spleen cells via the portal vein, but not the vena cava, show Ag-specific delayed rejection of allogeneic C3H.SW skin grafts. This delayed rejection is not seen if preimmunization is performed in gamma delta TCR knockout (C57BL/6-Tcrdtm1Mom) mice. gamma delta TCR+ and alpha beta TCR+ hybridoma cells were prepared from Peyer's patch cells harvested from C57BL/6 mice 4 days following portal venous immunization with 100 x 10(6) irradiated C3H.SW spleen cells and skin grafting with C3H.SW tail skin. After recloning, these hybridoma cells were tested for cytokine production in vitro following restimulation with irradiated C3H.SW spleen cells and for their ability to delay rejection of C3H.SW skin grafts after adoptive transfer to C57BL/6 mice. Delayed graft rejection was a function of cells that showed preferential production of IL-10, not IFN-gamma, in vitro, independent of the source (vena cava or portal vein immunized mice) or the TCR phenotype of the hybridoma. Simultaneous infusion of anti-IL-10 mAb abolished this graft prolongation effect of transferred gamma delta TCR+ hybridomas. Hybridoma cells producing IL-10 on restimulation could polarize cytokine production from freshly stimulated mesenteric lymph node away from production of IL-2 and IFN-gamma, and toward IL-4, IL-10, and TGF-beta production. This immunoregulation by hybridoma cells in vivo and in vitro was observed even for third party Ag-stimulated mice/cells as long as the hybridoma cells themselves received stimulation with their specific Ag.

Resistance of naive mice to murine hepatitis virus strain 3 requires development of a Th1, but not a Th2, response, whereas pre-existing antibody partially protects against primary infection

Murine hepatitis virus strain 3 (MHV-3) produces a strain-dependent spectrum of disease. The development of liver necrosis has been shown to be related to production of a unique macrophage procoagulant activity (PCA), encoded by the gene fgl-2, in susceptible mice. These studies were designed to examine the influence of Th1/Th2 cells on resistance/susceptibility and production of macrophage PCA in resistant (A/J) and susceptible (BALB/cJ) strains of mice following infection with MHV-3. Immunization of A/J mice with MHV-3 induced a Th1 cellular immune response, and one Th1 cell line (3E9.1) protected susceptible mice and inhibited PCA production by macrophages both in vitro and in vivo. In contrast, immunization of BALB/cJ mice with an attenuated variant of MHV-3 derived from passaging MHV-3 in YAC-1 cells resulted in a Th2 response. Transfer of spleen cells and T cell lines from immunized BALB/cJ mice failed to protect naive susceptible syngeneic mice from infection with MHV-3 and augmented macrophage PCA production to MHV-3 in vitro. However, serum from immunized BALB/cJ mice contained high titrated neutralizing Ab that protected naive BALB/cJ animals from lethal primary MHV-3 infection. These results demonstrate that susceptible BALB/cJ mice generate a Th2 response following MHV-3 infection and that these Th2 cells neither inhibit MHV-3-induced macrophage PCA production nor protect naive mice from MHV-3 infection. The results suggest that Ab protects against primary infection but cannot eradicate ongoing infection. Thus, these data define the differential role of Th1/Th2 lymphocytes in primary and secondary MHV-3 infection and emphasize the importance of PCA in the pathogenesis of MHV-3 infection.

Resistance of naive mice to murine hepatitis virus strain 3 requires development of a Th1, but not a Th2, response, whereas pre-existing antibody partially protects against primary infection

Murine hepatitis virus strain 3 (MHV-3) produces a strain-dependent spectrum of disease. The development of liver necrosis has been shown to be related to production of a unique macrophage procoagulant activity (PCA), encoded by the gene fgl-2, in susceptible mice. These studies were designed to examine the influence of Th1/Th2 cells on resistance/susceptibility and production of macrophage PCA in resistant (A/J) and susceptible (BALB/cJ) strains of mice following infection with MHV-3. Immunization of A/J mice with MHV-3 induced a Th1 cellular immune response, and one Th1 cell line (3E9.1) protected susceptible mice and inhibited PCA production by macrophages both in vitro and in vivo. In contrast, immunization of BALB/cJ mice with an attenuated variant of MHV-3 derived from passaging MHV-3 in YAC-1 cells resulted in a Th2 response. Transfer of spleen cells and T cell lines from immunized BALB/cJ mice failed to protect naive susceptible syngeneic mice from infection with MHV-3 and augmented macrophage PCA production to MHV-3 in vitro. However, serum from immunized BALB/cJ mice contained high titrated neutralizing Ab that protected naive BALB/cJ animals from lethal primary MHV-3 infection. These results demonstrate that susceptible BALB/cJ mice generate a Th2 response following MHV-3 infection and that these Th2 cells neither inhibit MHV-3-induced macrophage PCA production nor protect naive mice from MHV-3 infection. The results suggest that Ab protects against primary infection but cannot eradicate ongoing infection. Thus, these data define the differential role of Th1/Th2 lymphocytes in primary and secondary MHV-3 infection and emphasize the importance of PCA in the pathogenesis of MHV-3 infection.

Phenotypic and functional assessment of intraepithelial lymphocytes (IEL) isolated from rat colon and small bowel

We have compared the proliferative potential of IELs isolated from rat colon (CIEL) and small bowel (SBIEL), and compared this with that observed using spleen lymphocytes. Unless additional irradiated spleen cells were added as a source of accessory cells, both IEL populations show poor proliferation in response to Con A stimulation. The CD4/CD8 ratio in spleen, SBIEL and CIEL was markedly different (3:1, 1:3, and 1:1, respectively). Cells expressing surface markers characteristic of macrophages were not routinely found in SBIELs. Both IEL preparations inhibited spleen cell proliferation in response to Con A or immobilized anti-CD3, and produced a soluble factor(s) capable of causing similar inhibition. For CIEL this inhibition was dependent upon a proliferation-independent but cell-cell contact dependent event.

Altered patterns of migration of cytokine-producing T lymphocytes in skin-grafted naive or immune mice following in vivo administration of anti-VCAM-1 or -ICAM-1

Naive or preimmunized (to B10.BR or BALB.k) C3H/HeJ mice received skin grafts from multiple minor histoincompatible B10.BR or BALB.k mice following antigen-specific portal venous (p.v.) pretransplant transfusion, a protocol known to produce prolongation of graft survival in naive animals. In addition, groups of mice received intravenous (i.v.) infusion following transplantation with a mixture of monoclonal antibodies (mAb) to vascular adhesion molecule-1L: very late activation antigen-4 (VCAM-1:VLA-4) or intracellular adhesion molecule-1:lymphocyte function-associated antigen-3 (ICAM-1:LFA-1). Cells were harvested from different tissues of the grafted mice at various times post grafting. RNA was extracted and analysed, using polymerase chain reaction, for expression of different cytokines potentially involved in the regulation of graft rejection [interleukin-2 (IL-2), IL-4, IL-6, IL-10, tumour necrosis factor-alpha, interferon-gamma and transforming growth factor-beta]. In addition, using limiting dilution analysis, we investigated the frequency of allo-specific and third-party reactive cells producing IL-2 and IL-4 in vitro in different tissues of grafted mice following these treatments. The mAb treatment protocol which produced optimum increases in graft survival in naive versus immune mice was different, with anti-LFA-1:ICAM-1 superior for naive mice compared with anti-VLA-4:VCAM-1, and vice versa for immune animals. However, in each case, increased survival was associated with increases local to the graft in the frequency of occurrence of antigen-specific type-2 cytokine-producing cells.

A subset of gamma delta T-cell receptor-positive cells produce T-helper type-2 cytokines and regulate mouse skin graft rejection following portal venous pretransplant preimmunization

C3H/HeJ mice received B10.BR skin grafts following portal or lateral tail vein infusion of irradiated B10.BR spleen cells. Thereafter mice were injected with anti-alpha beta or anti-gamma delta T-cell receptor (TCR) monoclonal antibody (mAb). Anti-gamma delta TCR mAb abolished the increased graft survival afforded by portal venous (p.v.) immunization, and reversed the bias towards expression of mRNA for type-2 cytokines [interleukin-4 (IL-4), IL-10] seen in lymphoid tissue of p.v.-immunized mice. When gamma delta TCR+ and alpha beta TCR+ cells were isolated from the intestinal epithelial compartment (IEL), liver or Peyer's Patch (PP) of p.v.-immunized mice, the gamma delta TCR+ cells were found to be enriched in cells producing type-2 cytokines on rechallenge with irradiated B10.BR cells in vitro. gamma delta TCR+ cells from p.v.-immunized mice were further expanded in vitro with anti-CD3 and cytokines (combined IL-2 and IL-4). Following expansion these cells were capable of adoptively transferring increased B10.BR skin graft survival to naive mice, and continued to show a bias in type-2 cytokine synthesis after allostimulation in vitro. When gamma delta TCR chain expression was assessed in cells taken from p.v.-immunized mice, or in cells expanded in culture, our data suggest that p.v. immunization leads to oligoclonal, not polyclonal, expansion of those gamma delta TCR+ cells involved in inhibition of graft rejection.

Conditioned immunosuppression in orally immunized mice

Mice were given oral immunization after pretreatment with a regimen (cyclophosphamide and a novel taste in the drinking water, chocolate milk (CHM), which leads to suppression of the antibody response to intravenously administered antigens given concurrently with CHM. Following this treatment mice were reexposed to CHM and IgM and IgA antibody forming cells (AFC) were measured in spleen and Peyer's patch cells. Conditioned immunosuppression of AFC production was most marked (> fivefold) for IgA-AFC in Peyer's patch, with effects of lesser magnitude for IgM-AFC in Peyer's patch (twofold) and both IgM- and IgA-AFC in spleen. Analysis of cytokine production from stimulated Peyer's patch and splenic T cells in vitro showed significant decreased production of both IL-2 and IL-4, with the latter being the predominant cytokine produced in Peyer's patch cells of control animals.

Altered serum cytokines in hepatic and portal blood of rats at early times following portal venous infusion of semi-allogeneic cells

The liver of anaesthetized adult ( > 350 g) Lewis rats was perfused in vitro after cannulation of both the hepatic and portal vein, with clamping of the hepatic artery. Heparinized blood (400 microliters) was withdrawn at 0, 6, 12, 18, 24, 30 and 36 h from each site, and serum and peripheral blood lymphocytes (PBL) isolated after ficoll/hypaque separation. Serum was tested in bioassays for cytokines known to modulate lymphocyte:endothelial interactions in vivo and in vitro (IFN gamma, TGF beta, TNF alpha, IL-6, IL-1). In some experiments rats received, via portal venous infusion, a sterile inoculum of 150 x 10(6) semi-allogeneic (LBN F1) spleen cells immediately or 12 h after the start of the study. In animals which were unchallenged with cells via the portal vein, subtle differences in detectable cytokines were observed between hepatic and portal blood samples, as reported in earlier studies. Within 12 h the minor perturbations observed in cytokine profiles following surgical insult resolved, and the changes between hepatic and portal venous samples remained constant throughout the study in control rats. However, in rats treated with LBNF1 cells, changes in the cytokine profiles were seen compared with control animals, and as a function of time post F1 cell infusion. Changes in mRNAs for different cytokines were observed in PBL taken from portal/hepatic blood in these same animals. These data point to one possible mechanism whereby the liver may influence immunological processes following portal venous antigen challenge.

Interleukin 12 in combination with anti-interleukin 10 reverses graft prolongation after portal venous immunization

Portal venous pretransplantation transfusion augments allogeneic skin graft survival in mice transplanted across multiple minor histocompatibility barriers. We have shown in earlier studies that this is correlated with preferential activation for production of type-2 cytokines (interleukin [IL]-4 and IL-10) and decreased production of type-1 cytokines (IL-2 and interferon-gamma). We show that recombinant IL-12, in association with anti-IL-10 monoclonal antibody, can reverse in vivo the graft prolongation afforded by portal venous immunization and the altered cytokine production that follows. These alterations are in turn associated with increased expression of messenger RNA for interferon-gamma, IL-2, and IL-12 and decreased expression of IL-4, IL-10, and IL-13, as determined by non-quantitative polymerase chain reaction using cells obtained from lymph nodes draining the graft. Recombinant IL-12 in vitro also produces dose-related inhibition of activation for production of type-2 cytokines.

Manipulation of xenogeneic skin and/or renal graft survival in the rat-mouse concordant combination by portal vein pretransplant transfusion

We have examined whether portal venous pretransplant transfusion, which has been shown to produce prolongation of rodent vascularized (small intestine, kidney) and nonvascularized (skin) allografts, in the absence of other nonspecific immunosuppression, can produce similar graft prolongation in animals receiving vascularized or nonvascularized xeno- (not allo-) grafts. Rat kidney or skin grafts were transplanted into mice after portal venous pretreatment with rat or mouse spleen cells. Animals in some groups received additional immunosuppressive regimens including drug therapy (methotrexate, cyclosporin A) or monoclonal antibody treatment (anti-CD4, anti-CD8). Animal survival and serum creatinine was followed daily, and lymphoproliferation, cytokine production (including cytokine mRNA in grafted mice) and anti-xenograft antibody production was measured at distinct time points postgrafting. Both portal venous pretransplant transfusion and anti-CD4 monoclonal antibody treatment led to increased graft survival. However, unlike the rodent allograft model, graft survival in these animals was not simply explained by altered Th1/Th2 ratios. Other mechanism(s), possibly including xenoantibody production, are likely of importance in the regulation of xenograft rejection.

Role of reactive nitrogen intermediates in the regulation of allogeneic skin graft survival in mice after portal vein pretransplant transfusion

C3H/HeJ mice received multiple minor histoincompatible skin grafts (B10.BR) after portal or lateral tail vein injection of irradiated B10.BR spleen cells. Some mice were additionally injected with a competitive inhibitor of nitric oxide synthesis (NG-monomethyl-L-arginine [NMMA]). Skin graft survival was extended following portal venous immunization, and further enhanced by NMMA. Both treatments produced decreased production of nitrate/nitrite in vivo, and were associated with enhanced expression of mRNA in vivo for type 2 cytokines (interleukins 4 and 10), as well as increased synthesis of the latter on restimulation in vitro. Inducible nitric oxide synthase gene expression was up-regulated both in the local mucosal immune system (intraepithelial lymphocytes) and systemically (spleen) following antigen challenge by the portal vein or by gavage, with or without additional NMMA treatment. In contrast, when we studied a possible alternate in vivo source of nitric oxide production, we found that endothelial cell nitric oxide synthase expression was reproducibly up-regulated only in splenic tissue after combined oral (or portal) immunization and NMMA, and was not up-regulated in tissues local to the site of injection (intraepithelial lymphocytes).

Diurnal sleep/wake-related immune functions during the menstrual cycle of healthy young women

Animal and human studies have related the sleeping/waking brain to the immune system. Because women are more susceptible to certain immunological illnesses, and sex steroids regulate immune functions, it was investigated whether the diurnal sleep/wake pattern of aspects of cellular immune functions and interleukin-1 (IL-1) and IL-2-like activities differed during low and high progesterone phases of the menstrual cycle. Eleven healthy women, mean age 24 y, were assessed over 24 h with serial venous blood samples. Peripheral blood monocytes were assayed for mitogen responses, i.e. phytohemagglutin (PHA) and pokeweed (PWM) and natural killer (NK) cell activities. Plasma was assayed for IL-1 and IL-2-like activities, cortisol and progesterone. Data were standardized by Z transformation and analysed by repeated-measures analysis of variance by comparing high (N = 5) vs. low (N = 6) progesterone phases. During the high progesterone phase, delayed slow-wave sleep (SWS) onset time and reduced amount of SWS was accompanied by a delay in the decline of NK cell activity, but rise in PHA activity following sleep onset. With the low progesterone phase, the pattern was similar to men with an early sleep decline in NK cell and late sleep rise in PHA activities. PWM rose during the night and plasma IL-1-like activity peaked during midday and during nocturnal sleep irrespective of the amount of progesterone. Slow-wave sleep and sleep-related NK cell and PHA activities differed over the menstrual cycle, but not PWM response. Increases in plasma IL-1 functions during midday and night are consistent with predisposition to sleepiness during these times.

Evidence for Th2 cell-mediated suppression of antibody responses in transgenic, beef insulin-tolerant mice

Clonal deletion, anergy and suppression have all been considered mechanisms of immunological tolerance. Although adoptive transfer of immunosuppression has been shown to occur in the periphery, particularly for transplantation tolerance, it has proven difficult to characterize this phenomenon further, due to the lack of suppressor T cell clones. To characterize tolerance towards a physiological soluble antigen, we constructed beef insulin (BI) transgenic (Tg) BALB/c (H-2d) mice, in which the BI transgene is expressed in pancreatic beta cells. These Tg mice were tolerant to BI immunization at the level of both humoral and cell-mediated immune responses. Adoptive transfer of splenocytes from Tg mice into normal syngeneic BALB/c mice demonstrated that the reduction in antibody production is regulated by transferred T cells. The cytokine profile of T cell clones obtained after selection in vitro demonstrated dominant Th1 clones from normal non-Tg mice and dominant Th2 clones from Tg mice. Some Th2 clones (CD4+) from Tg mice produced significant suppression of antibody production after adoptive transfer into normal syngeneic BALB/c mice. These data confirm the existence of Th2 regulatory T cells in vivo in a model of peripheral tolerance to a physiological soluble antigen as a potential mechanism for self tolerance.

Induction of T-cell hyporesponsiveness by intrahepatic modulation of donor antigen-presenting cells

In this study, we examined the ability of varying populations of donor cells from B6 mice to induce hyporesponsiveness in T lymphocytes from C3H mice in vitro and in vivo. Small, resting B lymphocytes were inefficient stimulators of T-lymphocyte proliferation compared to splenic mononuclear cells (SMNC) and lipopolysaccharide (LPS)-induced B-cell blasts in vitro (P < 0.05). Pretreatment of SMNC with anti-B7-1 or anti-intracellular adhesion molecule-1 (ICAM-1) monoclonal antibodies (mAb) similarly resulted in inefficient stimulation of T-cell proliferation in vitro (P < 0.05). However, in vivo, only intrahepatic, but not intravenous, injection of donor cells into C3H mice resulted in decreased T-lymphocyte proliferation in response to restimulation by alloantigen. This effect was most pronounced following intrahepatic injection of resting B lymphocytes or SMNC pretreated with anti-ICAM-1 mAb compared to uninjected or intravenously injected mice (P < 0.05). The hyporesponsiveness was associated with an increased production of interleukin-4 (IL-4) by the responder T lymphocytes and correlated with enhanced skin allograft survival. These data demonstrate that intrahepatic injection of donor-derived cells induces T-lymphocyte hyporesponsiveness. The mechanism appears to be modulated by an ICAM-1-mediated signal resulting in expansion of an IL-4-producing T-lymphocyte population.

Regulation of IFN-gamma and IL-10 synthesis in vivo, as well as continuous antigen exposure, is associated with tolerance to murine skin allografts

C3H/HEJ mice are rendered hyporesponsive to multiple minor incompatible (B10.BR) skin allografts by pretreatment with irradiated B10.BR lymphoid cells injected via the portal vein, but not the lateral tail vein. As assessed by PCR with lymphocytes taken from grafted mice, or by measuring cytokines in vitro from antigen-restimulated cells, this hyporesponsiveness is associated with decreased mRNA for IFN-gamma and IL-2 production, but enhanced mRNA for IL-4 and IL-10 production. In mice given B10.BR cells via the tail vein, but in addition injected every second day with anti-IFN-gamma antibody, similar enhanced graft survival (with diminished IFN-gamma/IL-2 and enhanced IL-4/IL-10 production) was seen. In a separate study spleen cells from pretreated mice were "parked" in lethally irradiated syngeneic mice for 21 days, along with B10.BR skin grafts to some of the recipients. Only when recipients received this reexposure to B10.BR antigen did adoptively transferred spleen cells show "persistence" of the ability to produce delayed graft rejection and preferential IL-4 production in vitro.

A 2',5'-oligoadenylate analogue inhibits murine hepatitis virus strain 3 (MHV-3) replication in vitro but does not reduce MHV-3-related mortality or induction of procoagulant activity in susceptible mice

Exposure of inbred mice to murine hepatitis virus strain 3 (MHV-3) causes a strain dependent spectrum of disease symptoms which correlates with induction of procoagulant activity (PCA) by macrophages. Previous studies have demonstrated a role for interferons in resistance to MHV-3 infection. These cytokines have both antiviral and immunoregulatory effects which may be crucial for MHV-3 resistance. One of their antiviral effects is the ability to induce 2',5'-oligoadenylate (2-5A) synthetase leading to activation of the latent endoribonuclease RNase L. Once activated, RNase L degrades ssRNA thereby inhibiting viral-induced protein synthesis. These studies were undertaken to determine the effects of Oragen 0004 (Oragen), an RNase L activating 2-5A analogue, on MHV-3 replication and induction of PCA in vitro and on the course of MHV-3 infection in susceptible BALB/cJ mice in vivo. Oragen inhibited MHV-3 replication in peritoneal macrophages derived from resistant A/J and susceptible BALB/cJ mice in a dose-dependent fashion. Concentrations of Oragen greater than 110 micrograms/2 x 10(6) macrophages decreased viral replication by greater than 89% in peritoneal macrophages in vitro obtained from both BALB/cJ and A/J mice and by 86% in livers from MHV-3-infected mice in vivo. However, Oragen failed to inhibit induction of PCA following in vitro exposure of BALB/cJ mice-derived peritoneal macrophages to MHV-3 and failed to prevent the development of fulminant hepatitis in BALB/cJ mice in vivo. Thus, these studies demonstrate clearly that induction of 2-5A synthase and inhibition of viral replication is not sufficient to prevent MHV-3-related hepatocellular injury, and these data further support the role of PCA in the pathogenesis of MHV-3 infection.

Prolongation of rat small bowel or renal allograft survival by pretransplant transfusion and/or by varying the route of allograft venous drainage

Lewis rats show prolongation of survival of LBNF1 renal allografts when those grafts are drained by the portal vein, or if recipients are treated with LBNF1 bone marrow cells infused via the portal venous route peritransplantation. The longest survival was seen in animals in which both portal venous transfusion and graft drainage by the portal route were performed. When the same manipulations were performed for Lewis rats receiving heterotopic small bowel transplants, only in the "combined treatment" group was there significantly enhanced graft or animal survival relative to control rats. In separate studies, we examined the mixed leukocyte proliferation response in vitro, and IL-2 production, from rats treated as above and receiving renal or small bowel transplants. In both organ transplant models, there was a good correlation between enhanced graft survival in vivo and decreased in vitro responses to specific allostimulation.

Hepatic regulation of lymphocyte adhesion to, and activation on, syngeneic endothelial monolayers

Endothelial monolayers were prepared from neonatal heart or liver tissue of Lewis (Le) rats. Cells in their first passage of culture were used to investigate the short-term (1 hr at 37 degrees) binding of 51Cr-labelled Le rat lymphocytes prepared from the mesenteric lymph node (MLN), peripheral lymph node (PLN) or Peyer's patches (PP) to those endothelia, or the activation by concanavalin A (Con A) or irradiated (Lewis x Brown Norway)F1 (LBNF1), of Le cells on the monolayers after 84 hr in culture. MLN and PP showed preferential binding to, and activation on, liver endothelium compared with heart endothelium (approximately twofold difference), while the converse was seen with PLN. No inhibition of binding was seen with antibodies to intracellular adhesion molecule-1 (ICAM-1) or lymphocyte function-associated antigen-1 (LFA-1). Preincubation of endothelial cells with plasma isolated from the portal or hepatic vein of normal adult mice (5% plasma, 37 degrees for 14 hr) caused a 1.5-2-fold stimulation of binding of MLN/PP to heart endothelium, which was inhibited (> or = 75%) by anti-ICAM-1 or anti-LFA-1, and a fourfold stimulation of binding to liver endothelium, which was not inhibited by these monoclonal antibodies (< or = 25% inhibition). In contrast, antibodies to tumour necrosis factor-alpha (TNF-alpha) or interleukin-6 (IL-6) caused inhibition of activation of liver endothelium (> or = 75%), while producing little affect on activation of heart endothelium. Similar results were seen when lymphocyte activation on endothelial cells rather than adhesion cells was investigated. Our data suggest a heterogeneity in lymphocyte-endothelial interactions, which is further regulated, under physiological conditions, by the liver.

Tolerance induction to multiple minor histoincompatible cells by activated B cells is associated with preferential activation of Th2 cells

C3H/HeH or C57BL/6 mice were injected with resting or Escherichia coli lipopolysaccharide (LPS)-stimulated splenic B cells from adult B10.BR mice. Animals were grafted with tail skin grafts from B10.BR mice 36 hr later. Spleen cells were removed from these mice 7 days after grafting and challenged in tissue culture with irradiated B10.BR spleen cells or BALB/c cells. LPS blasts, but not naive B cells, induced an antigen-specific reduction in proliferation and IL-2 production from stimulated C3H/HeJ cells. The response obtained from C57BL/6 spleen responder cells was increased by this treatment. IL-4 production was either unchanged (C57BL/6) or enhanced (C3H/HeJ). Modification of the C3H/HeJ anti-B10.BR response by B blasts was not blocked by CTLA-4 Ig, although the increased response seen using MHC-incompatible (C57BL/6) spleen cells was inhibited by CTLA-4 Ig. B10.BR, but not BALB/c, skin graft survival in vivo was enhanced in C3H/HeJ recipients of B10.BR B blasts. In addition, in lymph nodes draining the graft site of C3H/HeJ mice injected with B10.BR LPS blasts, mRNA for IL-4 was detected by polymerase chain reaction. When similar studies were performed with B10.BR immune C3H/HeJ or C57BL/6 mice, no enhancement of graft survival in vivo, or decrease in proliferation/IL-2 production in vitro, was seen following prechallenge with B10.BR LPS blasts.

A role for nonspecific (cyclosporin A) or specific (monoclonal antibodies to ICAM-1, LFA-1, and IL-10) immunomodulation in the prolongation of skin allografts after antigen-specific pretransplant immunization or transfusion

C3H/HEJ mice given pretransplant immunization via the portal vein with irradiated B10.BR spleen cells or non-irradiated B10.BR peripheral blood leukocytes showed delayed rejection of B10.BR but not BALB.K skin grafts. No increased graft survival was seen if pretransplant immunization was given by the lateral tail vein. Addition of a single treatment with cyclosporin A after pretransplant immunization via the portal vein led to indefinite graft survival in over 70% of recipients. As reported earlier, increased graft survival in vivo was correlated with preferential production of IL-4 (from Th2 type cells) rather than IL-2 from lymphocytes stimulated in vitro. When mice were given pretransplant transfusion via the lateral tail vein and a combination of anti-LFA-1 and anti-ICAM-1 mAbs, increased graft survival was again seen. In addition, in vivo injection of anti-IL-10 mAbs (but not anti-IFN-gamma or anti-IL-4 mAbs) abolished the delayed rejection seen when mice received pretransplant immunization via the portal vein. In all cases, delayed graft rejection in vivo was correlated with preferential activation of Th2-type cells, as assessed by lymphokine production from cells harvested from treated mice and activated in vitro.

A role for nonspecific (cyclosporin A) or specific (monoclonal antibodies to ICAM-1, LFA-1, and IL-10) immunomodulation in the prolongation of skin allografts after antigen-specific pretransplant immunization or transfusion

C3H/HEJ mice given pretransplant immunization via the portal vein with irradiated B10.BR spleen cells or non-irradiated B10.BR peripheral blood leukocytes showed delayed rejection of B10.BR but not BALB.K skin grafts. No increased graft survival was seen if pretransplant immunization was given by the lateral tail vein. Addition of a single treatment with cyclosporin A after pretransplant immunization via the portal vein led to indefinite graft survival in over 70% of recipients. As reported earlier, increased graft survival in vivo was correlated with preferential production of IL-4 (from Th2 type cells) rather than IL-2 from lymphocytes stimulated in vitro. When mice were given pretransplant transfusion via the lateral tail vein and a combination of anti-LFA-1 and anti-ICAM-1 mAbs, increased graft survival was again seen. In addition, in vivo injection of anti-IL-10 mAbs (but not anti-IFN-gamma or anti-IL-4 mAbs) abolished the delayed rejection seen when mice received pretransplant immunization via the portal vein. In all cases, delayed graft rejection in vivo was correlated with preferential activation of Th2-type cells, as assessed by lymphokine production from cells harvested from treated mice and activated in vitro.

Adoptive transfer of unresponsiveness to allogeneic skin grafts with hepatic gamma delta + T cells

C3H/HEJ mice injected with irradiated multiple minor incompatible B10.BR lymphoid cells via the portal vein showed delayed rejection of subsequent B10.BR skin grafts. Similar delayed rejection was produced by lateral tail vein injection of B10.BR hepatic mononuclear cells or H-2k cells pulsed in vivo with B10 minor histocompatibility antigens. Inhibition of C3H anti-B10.BR immunity in vivo (assessed by delayed graft rejection) and in vitro (assessed by B10.BR-induced lymphokine production) can be transferred by radioresistant, plastic-adherent F4/80+33D1-CD4-CD8-alpha beta TcR-gamma delta TcR- mononuclear hepatic cells from (C3H/HEJ x C3H.SW)F1 mice injected 36 hr earlier with 100 x 10(6) irradiated spleen cells. By 10 days post-injection, cells transferring delayed rejection are radiosensitive, plastic non-adherent, F4/80-33D1-CD4-CD8- alpha beta Tc+- gamma delta TcR+ cells. Injection of interleukin-2 (IL-2) in vivo into mice receiving pretreatment with B10.BR cells via the portal vein, or adoptive transfer into such mice of immune anti-B10.BR lymphoid cells, abolished delayed rejection on subsequent skin grafting. Delayed rejection or modulation of lymphokine production was associated in all cases with suppression of IL-2 production and preferential retention of IL-4 production from cells stimulated in vitro.