In Vivo Development of Transplant Arteriosclerosis in Humanized Mice Reflects Alloantigen Recognition and Peripheral Treg Phenotype of Lung Transplant Recipients

Experimentally, regulatory T cells inhibit rejection. In clinical transplantations, however, it is not known whether T cell regulation is the cause for, or an epiphenomenon of, long‐term allograft survival. Here, we study naïve and alloantigen‐primed T cell responses of clinical lung transplant recipients in humanized mice. The pericardiophrenic artery procured from human lung grafts was implanted into the aorta of NODrag^?/?/IL‐2rγc^?/? mice reconstituted with peripheral blood mononuclear cells (PBMCs) from the respective lung recipient. Naïve or primed allogeneic PBMCs procured 21 days post–lung transplantation with or without enriching for CD4⁺CD25^high T cells were used. Transplant arteriosclerosis was assessed 28 days later by histology. Mice reconstituted with alloantigen‐primed PBMCs showed significantly more severe transplant arteriosclerosis than did mice with naïve PBMCs (p = 0.005). Transplant arteriosclerosis was equally suppressed by enriching for autologous naïve (p = 0.012) or alloantigen‐primed regulatory T cells (Tregs) (p = 0.009). Alloantigen priming in clinical lung recipients can be adoptively transferred into a humanized mouse model. Transplant arteriosclerosis elicited by naïve or alloantigen‐primed PBMCs can be similarly controlled by potent autologous Tregs. Cellular therapy with expanded autologous Tregs in lung transplantation might be a promising future strategy.     

Relative Resistance of Human CD4+ Memory T Cells to Suppression by CD4+CD25+ Regulatory T Cells

Successful expansion of functional CD4⁺CD25⁺ regulatory T cells (T_reg) ex vivo under good manufacturing practice conditions has made T_reg‐cell therapy in clinical transplant tolerance induction a feasible possibility. In animals, T_reg cells home to both transplanted tissues and local lymph nodes and are optimally suppressive if active at both sites. Therefore, they have the opportunity to suppress both naïve and memory CD4⁺CD25^? T cells (Tresp). Clinical transplantation commonly involves depleting therapy at induction (e.g. anti‐CD25), which favors homeostatic expansion of memory T cells. Animal models suggest that T_reg cells are less suppressive on memory, compared with naïve Tresp that mediate allograft rejection. As a result, in the context of human T_reg‐cell therapy, it is important to define the effectiveness of T_reg cells in regulating naïve and memory Tresp. Therefore, we compared suppression of peripheral blood naïve and memory Tresp by fresh and ex vivo expanded T_reg cells using proliferation, cytokine production and activation marker expression (CD154) as readouts. With all readouts, naïve human Tresp were more suppressible by approximately 30% than their memory counterparts. This suggests that T_reg cells may be more efficacious if administered before or at the time of transplantation and that depleting therapy should be avoided in clinical trials of T_reg cells.     

Critical role of natural killer cells in the rejection of human hepatocytes after xenotransplantation into immunodeficient mice

The severe combined immunodeficiency/albumin linked‐urokinase type plasminogen activator (SCID/Alb‐uPA) human liver chimeric mouse model has added a new dimension to studies of liver based human diseases and has important potential for study of human hepatic drug metabolism. However, it remains unclear if natural killer (NK) cell in SCID/Alb‐uPA mice has an important negative impact on engraftment and expansion of human hepatocytes after transplantation. Here, we explore the role of mouse NK cells in the rejection of transplanted human hepatocytes in SCID/Alb‐uPA mice. We assessed NK cell activity in vivo, using ¹²⁵I‐iodo‐2′‐deoxyuridine incorporation assay. Low serum human alpha‐1 antitrypsin (hAAT, <10 μg/ml) recipients, representing graft failure, showed resistance to engraftment of MHC class I knockout marrow (indicating high NK cell activity), while NK cell‐depleted low hAAT recipients and high hAAT (>100 μg/ml) recipients accepted MHC class I knockout marrow, indicating a correlation between low NK cell activity, in vivo, and high level human hepatocyte engraftment. We also showed that higher level engraftment of human hepatocytes was achieved in both NK cell‐depleted SCID/Alb‐uPA mice and Rag2^?/?γc^?/?/Alb‐uPA (T,B and NK cell deficient) mice compared with untreated SCID/Alb‐uPA mice. These results support a critical role for mouse NK cells in the rejection of human hepatocytes xenotransplanted to immunodeficient mice.     

In vitro equine embryo production using air‐dried spermatozoa,with different activation protocols and culture systems

The aim of this work was to evaluate the use of air‐dried spermatozoa for in vitro production of equine embryos and verify if sperm extract activation and in vivo culture improve in vitro embryo production. Cooled spermatozoa (control) and air‐dried spermatozoa stored for 2, 14 or 28 days were used for ICSI sperm extract, or ionomycin was used for oocyte activation, and embryos were in vitro or in vivo (in mare′s oviduct) cultured for 7 days. With in vitro culture, cleavage rate was higher when activating with sperm extract (P < 0.05). No differences in embryo development were seen between the two activation treatments nor between storage periods (P > 0.05). Blastocysts were obtained with cooled spermatozoa, and morulae were achieved using in vivo culture with 28‐day storage spermatozoa and ionomycin‐activated oocytes. When in vivo culture was performed, sperm DNA fragmentation was assessed using the sperm chromatin dispersion test and did not show statistical correlation with cleavage nor embryo recovery rates. In conclusion, equine embryos can be produced using air‐dried spermatozoa stored for several weeks. Sperm extract activation increased cleavage rates but did not improve embryo development. In vivo culture allowed intrauterine stage embryos to be achieved.     

Anti‐TCRβ mAb Induces Long‐Term Allograft Survival by Reducing Antigen‐Reactive T Cells and Sparing Regulatory T Cells

TCR specific antibodies may modulate the TCR engagement with antigen–MHC complexes, and in turn regulate in vivo T cell responses to alloantigens. Herein, we found that in vivo administration of mAbs specific for mouse TCRβ (H57–597), TCRα or CD3 promptly reduced the number of CD4⁺ and CD8⁺ T cells in normal mice, but H57–597 mAb most potently increased the frequency of CD4⁺Foxp3⁺ Treg cells. When mice were injected with staphylococcal enterotoxin B (SEB) superantigen and H57–597 mAb, the expansion of SEB‐reactive Vβ8⁺ T cells was completely abrogated while SEB‐nonreactive Vβ2⁺ T cells remained unaffected. More importantly, transient H57–597 mAb treatment exerted long‐lasting effect in preventing T cell responses to alloantigens, and produced long‐term cardiac allograft survival (>100 days) in 10 out of 11 recipients. While Treg cells were involved in maintaining donor‐specific long‐term graft survival, T cell homeostasis recovered over time and immunity was retained against third party allografts. Moreover, transient H57–597 mAb treatment significantly prolonged survival of skin allografts in naïve recipients as well as heart allografts in skin‐sensitized recipients. Thus, transient modulation of the TCRβ chain by H57–597 mAb exhibits potent, long‐lasting therapeutic effects to control alloimmune responses.     

Primed allospecific T cells prevent the effects of costimulatory blockade on prolonged cardiac allograft survival in mice.

Costimulatory blockade can induce long‐term allograft survival in naïve animals, but may not be as effective in animals with previously primed immune repertoires. We attempted to induce long‐term graft survival in B10.D2 recipients of B10.A cardiac allografts using donor‐specific transfusion (DST) plus anti‐CD40 ligand antibody (αCD40L). Recipients were either naïve mice, or mice previously primed to B10.A or third party alloantigens through engraftment and rejection of skin transplants. Untreated naïve mice rejected cardiac transplants by day 15 and contained a high frequency of primed, donor‐reactive T cells. Donor‐specific transfusion/αCD40L treatment of naïve animals induced long‐term graft survival associated with low frequencies of donor‐reactive T cells. Previous priming of donor‐specific T cells through rejection of B10.A, but not third party, skin grafts prevented the effects of DST/αCD40L on prolonging survival of B10.A hearts. Moreover, adoptive transfer of CD3+, CD4+ or CD8+ T cells from B10.A skin‐graft‐primed animals prevented the effects of DST/αCD40L. The data demonstrate that animals with immune repertoires containing previously primed, donor‐reactive T cells are resistant to the effects of costimulatory blockade. The findings have important implications for ongoing, costimulatory blockade‐based trials in humans, whose T‐cell repertoires are known to contain memory alloreactive T cells.     

Different Mechanisms Control Peripheral and Central Tolerance in Hematopoietic Chimeric Mice

Regulatory T cells (Treg) are important in peripheral tolerance, but their role in establishing and maintaining hematopoietic mixed chimerism and generating central tolerance is unclear. We now show that costimulation blockade using a donor‐specific transfusion and anti‐CD154 antibody applied to mice given bone marrow and simultaneously transplanted with skin allografts leads to hematopoietic chimerism and permanent skin allograft survival. Chimeric mice bearing intact skin allografts fail to generate effector/memory T cells against allogeneic targets as shown by the absence of IFNγ‐producing CD44^highCD8⁺ T cells and in vivo cytotoxicity. Depletion of Tregs by injection of anti‐CD4 or anti‐CD25 antibody prior to costimulation blockade prevents chimerism, shortens skin allograft survival and leads to generation of effector/memory cytotoxic T cells. Depletion of Tregs by injection of anti‐CD4 or anti‐CD25 antibody two months after transplantation leads to loss of skin allografts even though mice remain chimeric and exhibit little in vivo cytotoxicity. In contrast, chimerism is lost, but skin allografts survive following naïve T‐cell injection. We conclude that hematopoietic chimerism and peripheral tolerance may be maintained by different mechanisms in mixed hematopoietic chimeras.     

Transplant Acceptance Following Anti‐CD4 Versus Anti‐CD40L Therapy: Evidence for Differential Maintenance of Graft‐Reactive T Cells

Inductive therapy with anti‐CD4 or anti‐CD40L monoclonal antibodies (mAb) leads to long‐term allograft acceptance but the immune parameters responsible for graft maintenance are not well understood. This study employed an adoptive transfer system in which cells from mice bearing long‐term cardiac allografts following inductive anti‐CD4 or anti‐CD40L therapy were transferred into severe combined immunodeficiency (SCID) allograft recipients. SCID recipients of cells from anti‐CD4‐treated mice (anti‐CD4 cells) did not reject allografts while those receiving cells from anti‐CD40L‐treated mice (anti‐CD40L cells) did reject allografts. Carboxyfluorescein succinimidyl ester (CFSE) labeling of transferred cells revealed that this difference was not associated with differential proliferative capacities of these cells in SCID recipients. Like cells from naïve mice, anti‐CD40L cells mounted a Th1 response following transfer while anti‐CD4 cells mounted a dominant Th2 response. Early (day 10) T‐cell priming was detectable in both groups of primary allograft recipients but persisted to day 30 only in recipients treated with anti‐CD4 mAb. Thus, anti‐CD40L therapy appears to result in graft‐reactive T cells with a naïve phenotype while anti‐CD4 therapy allows progression to an altered state of differentiation. Additional data herein support the notion that anti‐CD40L mAb targets activated, but not memory, cells for removal or functional silencing.     

The Effect of Desensitization Protocols on Human Splenic B-Cell Populations In Vivo

Rituximab, intravenous immunoglobulin (IVIG) and rabbit antithymocyte globulin (rATG) all have been suggested to have an effect on antibody producing cells, however, supporting data are lacking. To assess the impact of these agents on splenic B‐cell populations in vivo, we retrospectively examined 25 spleens removed from patients treated with these agents as part of desensitization protocols in either ABO incompatible or positive crossmatch living donor kidney transplantation. These were compared to control (CTL) spleens removed for trauma. CTLs and spleens removed at transplant after multiple pretransplant plasmaphereses (PP) plus low‐dose IVIG showed similar large numbers of naïve B cells (CD20⁺ and CD79⁺), plasma cells (CD138⁺) and memory B cells (CD27⁺ cells). Adding rituximab to this PP/IVIG regimen reduced the number naïve B cells, but had no effect on memory or plasma cells. Combination treatment (PP/IVIG, rituximab and rATG) showed a trend toward the reduction of CD27⁺ cells, but again plasma cells were unchanged. We conclude that none of these protocols reduces splenic plasma cells in vivo. PP/low‐dose IVIG does not alter splenic B cells, but the addition of rituximab decreases mature B cells. Memory B cells may be affected by combination therapy including rATG and requires further study.     

Polymethylmethacrylate and titanium alloy particles activate peripheral monocytes during periprosthetic inflammation and osteolysis

We investigated the interactions of particulate PMMA or titanium alloy, patient blood monocytes, and periprosthetic tissues using a SCID‐hu model of aseptic loosening. Periprosthetic tissues and bone chips obtained at revision surgery for loosening were transplanted into muscles of SCID mice. Peripheral blood monocytes (PBMCs) isolated from the same donors were fluorescently labeled and co‐cultured with PMMA or Ti‐6Al‐4V particles before intraperitoneal injection. Control mice with periprosthetic tissue or non‐inflammatory ligament xenografts received naive PBMCs transfusion. Mice were euthanized 2 weeks after PBMC transfusion. The human tissues were well accepted in SCID mice. Transfused fluorescent‐labeled PBMCs were markedly accumulated in transplanted periprosthetic tissues. Multinucleated osteoclast‐like cells were commonly seen within retrieved xenograft tissue, and focal bone erosions were ubiquitous. Total cell densities and CD68+ cells within the xenograft were significantly increased in mice transfused with PMMA and Ti‐provoked PBMCs compared to the naïve PBMC animals (p < 0.05). Immunohistochemical staining identified much stronger positive IL‐1 and TNF stains in xenografts from either PMMA or Ti‐stimulated monocytes transfusion groups (p < 0.05). TRAP+ cells were found around bone chips in both activated‐PBMCs groups, although markedly more aggregated TRAP+ cells in the PMMA‐challenged group than in the titanium group (p < 0.05). MicroCT assessment confirmed the significant decrease of bone mineral density in chips interacted with activated‐monocytes/osteoclasts. In conclusion, PMMA or titanium particles readily activate peripheral monocytes and promote the cell trafficking to the debris‐containing prosthetic tissues. Particles‐provoked PBMCs participated in and promoted the local inflammatory process, osteoclastogenesis, and bone resorption. © 2010 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res 29:781–786, 2011     

Low‐Dose Rapamycin Treatment Increases the Ability of Human Regulatory T Cells to Inhibit Transplant Arteriosclerosis In Vivo

Regulatory T cells (T_reg) are currently being tested in clinical trials as a potential therapy in cell and solid organ transplantation. The immunosuppressive drug rapamycin has been shown to preferentially promote T_reg expansion. Here, we hypothesized that adjunctive rapamycin therapy might potentiate the ability of ex vivo expanded human T_reg to inhibit vascular allograft rejection in a humanized mouse model of arterial transplantation. We studied the influence of combined treatment with low‐dose rapamycin and subtherapeutic T_reg numbers on the development of transplant arteriosclerosis (TA) in human arterial grafts transplanted into immunodeficient BALB/cRag2^?/?Il2rg^?/? mice reconstituted with allogeneic human peripheral blood mononuclear cell. In addition, we assessed the effects of the treatment on the proliferation and apoptosis of naïve/effector T cells. The combined therapy efficiently suppressed T‐cell proliferation in vivo and in vitro. Neointima formation in the human arterial allografts was potently inhibited compared with each treatment alone. Interestingly, CD4⁺ but not CD8⁺ T lymphocytes were sensitive to T_reg and rapamycin‐induced apoptosis in vitro. Our data support the concept that rapamycin can be used as an adjunctive therapy to improve efficacy of T_reg‐based immunosuppressive protocols in clinical practice. By inhibiting TA, T_reg and rapamycin may prevent chronic transplant dysfunction and improve long‐term allograft survival.     

Induction of regulatory T cells from mature T cells by allogeneic thymic epithelial cells in vitro

The ability of thymic epithelial cells (TEC) to re‐educate mature T cells to be regulatory T cells has not been addressed. In the present study, this issue was directly investigated by co‐culturing of mature T cells and allo‐TECs. B6 macrophage cell line 1C21‐cultured BALB/c splenocytes responded to B6 antigens in vitro. However, BALB/c splenocytes precultured with B6‐derived TECs 1‐4C18 or 1C6 did not proliferate to B6 antigens, but responded to rat antigens. Exogenous interleukin‐2 (IL‐2) failed to revise the unresponsiveness of these T cells. Allo‐TEC‐cultured T cells predominantly expressed Th2 cytokines (IL‐4 and IL‐10). B6 TEC‐cultured BALB/c splenocytes markedly inhibited the immune responses of naïve BALB/c splenocytes to B6 antigens, but not to rat or the third‐party mouse antigens. BALB/c nude mice that received naïve syngeneic splenocytes rejected B6 or rat skin grafts by 17 days postskin grafting; however, co‐injection of B6 TEC‐cultured BALB/c splenocytes significantly delayed B6 skin graft rejection (P < 0.01), with the unchanged rejection of rat skin grafts. These studies demonstrate that allo‐TECs are able to ‘educate’ mature T cells to be regulatory cells, and suggest that regulatory cells derived from mature T cells by TECs may play an important role in T cell tolerance to allo‐ and auto‐antigens.     

Low‐Dose IL‐2 for In Vivo Expansion of CD4+ and CD8+ Regulatory T Cells in Nonhuman Primates

IL‐2 is a known potent T cell growth factor that amplifies lymphocyte responses in vivo. This capacity has led to the use of high‐dose IL‐2 to enhance T cell immunity in patients with AIDS or cancer. However, more recent studies have indicated that IL‐2 is also critical for the development and peripheral expansion of regulatory T cells (Tregs). In the current study, low‐dose IL‐2 (1 million IU/m² BSA/day) was administered to expand Tregs in vivo in naïve nonhuman primates. Our study demonstrated that low‐dose IL‐2 therapy significantly expanded peripheral blood CD4⁺ and CD8⁺ Tregs in vivo with limited expansion of non‐Treg cells. These expanded Tregs are mainly CD45RA^? Foxp3 ^high activated Tregs and demonstrated potent immunosuppressive function in vitro. The results of this preclinical study can serve as a basis to develop Treg immunotherapy, which has significant therapeutic potential in organ/cellular transplantation.     

T cells with low CD2 levels express reduced restriction factors and are preferentially infected in therapy naïve chronic HIV‐1 patients

Introduction : Restriction factors (RFs) suppress HIV‐1 in cell lines and primary cell models. Hence, RFs might be attractive targets for novel antiviral strategies, but their importance for virus control in vivo is controversial. Methods : We profiled the expression of RFs in primary blood‐derived mononuclear cells (PBMC) from therapy‐naïve HIV‐1 patients and quantified infection. Results : Overall, there was no correlation between individual RF expression and HIV‐1 status in total PBMC. However, we identified a T cell population with low levels of intracellular CD2 and reduced expression of SAMHD1, p21 and SerinC5. CD2^low T cells with reduced RF expression were markedly positive for HIV‐1 p24. In contrast, CD2+ T cells were less infected and expressed higher levels of RFs. CD2^low T cell infection correlated with viral loads and was associated with HIV‐1 disease progression. Conclusions : In untreated therapy naïve chronic HIV‐1 patients, RF expression in T cells is associated with CD2 expression and seems to influence viral loads. Our study suggests that RFs help to control HIV‐1 infection in certain T cells in vivo and supports the potential for RFs as promising targets for therapeutic intervention.     

Effect of You Gui Wan on mouse sperm fertilising ability in vivo and in vitro

This study is to explore whether YGW has an impact on sperm fertilising ability in mice. Twenty male mice were randomly divided into two groups. In vivo experiments, one group of animals were orally administrated with YGW decoction and another group administered with saline for 14 days. Afterwards, the animals were mated with their female partners. Percentages of retrieved zygotes were then compared. In vitro experiments, in vitro fertilisation (IVF) assay, sperm acrosome reaction and acrosin activity were used to compare sperm fertilising ability between the two groups. The YGW‐treated group had a significantly higher percentage of zygotes than the saline controls (P = 0.005). The IVF rates induced by spermatozoa from the herb‐treated mice were also significantly higher than those from the control animals (P = 0.015). The sperm acrosin activity of the herb‐treated group was significantly higher than that of the saline‐treated group (P = 0.048), although there was no significant difference in testicular weight, sperm count and sperm motility. These data suggest that YGW decoction has a significant effect on normal sperm fertilising ability both in vivo and in vitro, which may be due to, at least in part, increments in the sperm acrosin activity.     

Sensitization to Minor Antigens Is a Significant Barrier in Bone Marrow Transplantation and Is Prevented by CD154:CD40 Blockade

Sensitization to major histocompatibility complex (MHC) alloantigens is critical in transplantation rejection. The mechanism of sensitization to minor histocompatibility antigens (Mi‐HAg) has not been thoroughly explored. We used a mouse model of allosensitization to Mi‐HAg to study the Mi‐HAg sensitization barrier in bone marrow transplantation (BMT). AKR mice were sensitized with MHC congenic Mi‐HAg disparate B10.BR skin grafts. Adaptive humoral (B‐cells) and cellular (T cells) responses to Mi‐HAg are elicited. In subsequent BMT, only 20% of sensitized mice engrafted, while 100% of unsensitized mice did. In vivo cytotoxicity assays showed that Mi‐HAg sensitized AKR mice eliminated CFSE labeled donor splenocytes significantly more rapidly than naïve AKR mice but less rapidly than MHC‐sensitized recipients. Sera from Mi‐HAg sensitized mice also reacted with cells from other mouse strains, suggesting that Mi‐HAg peptides were broadly shared between mouse strains. The production of anti‐donor‐Mi‐HAg antibodies was totally prevented in mice treated with anti‐CD154 during skin grafting, suggesting a critical role for the CD154:CD40 pathway in B‐cell reactivity to Mi‐HAg. Moreover, anti‐CD154 treatment promoted BM engraftment to 100% in recipients previously sensitized to donor Mi‐HAg. Taken together, Mi‐HAg sensitization poses a significant barrier in BMT and can be overcome with CD154:CD40 costimulatory blockade.     

Development of human B cells and antibodies following human hematopoietic stem cell transplantation to Rag2−/−γc−/− mice

Humanized mice represent a valuable model system to study the development and functionality of the human immune system. In the RAG-hu mouse model highly immunodeficient Rag2^−/−γc^−/− mice are transplanted with human CD34⁺ hematopoietic stem cells, resulting in human hematopoiesis and a predominant production of B and T lymphocytes. Human adaptive immune responses have been detected towards a variety of antigens in humanized mice but both cellular and humoral immune responses tend to be weak and sporadically detected. The underlying mechanisms for inconsistent responses are poorly understood. Here, we analyzed the kinetics of human B cell development and antibody production in RAG-hu mice to better understand the lack of effective antibody responses. We found that T cell levels in blood did not significantly change from 8 to 28 weeks post-engraftment, while B cells reached a peak at 14 weeks. Concentrations of 3 antibody classes (IgM, IgG, IgA) were found to be at levels about 0.1% or less of normal human levels, but human antibodies were still detected up to 32 weeks after engraftment. Human IgM was detected in 92.5% of animals while IgG and IgA were detected in about half of animals. We performed flow cytometric analysis of human B cells in bone marrow, spleen, and blood to examine the presence of precursor B cells, immature B cells, naïve B cells, and plasma B cells. We detected high levels of surface IgM⁺ B cells (immature and naïve B cells) and low levels of plasma B cells in these organs, suggesting that B cells do not mature properly in this model. Low levels of human T cells in the spleen were observed, and we suggest that the lack of T cell help may explain poor B cell development and antibody responses. We conclude that human B cells that develop in humanized mice do not receive the signals necessary to undergo class-switching or to secrete antibody effectively, and we discuss strategies to potentially overcome these barriers.     

In vitro effects of nonylphenol on motility,mitochondrial, acrosomal and chromatin integrity of ram and boar spermatozoa

The objective of this study was to determine the effects of nonylphenol (NP) on viability of ram and boar sperm in vitro. Ram or boar spermatozoa were exposed to 1, 10, 100, 250 and 500 μg NP ml^?1 for 1, 2, 3 or 4 h. Computer‐assisted sperm motility analysis (CASA) system was used to evaluate sperm motility characteristics. Flow cytometry was used to determine mitochondrial membrane potential (MMP) and chromatin integrity, while epifluorescent microscopy was used to determine sperm acrosomal status. Exposure of both species spermatozoa to 250 and 500 μg NP ml^?1 was detrimental to progressive motility (P < 0.05), and its adverse effect was significant at lower (100 μg NP ml^?1) concentration (P < 0.05). The percentages of ram and boar spermatozoa with high MMP declined drastically after exposures to ≥250 μg ml^?1 NP (P < 0.05). Unlike chromatin integrity, which did not appear to be altered by NP exposure, there were dose‐dependent NP effects (P < 0.05) on acrosomal integrity of both species at as low as 1 μg ml^?1 NP for boar spermatozoa and 10 μg ml^?1 NP for ram spermatozoa. These data show adverse effects of NP on ram and boar spermatozoa and thus its potential harmful effects on male reproduction as NP is found in fruits, vegetables, human milk, fish and livestock products.     

Vasectomy in rhesus monkeys II. Failure to demonstrate dumoral and cellular immune responses specific for sperm.

A study designed to determine whether humoral antibodies and a cell-mediated immune response to sperm antigen(s) in rhesus monkeys after unilateral and bilateral vas ligations has revealed negative findings. Kibrick agglutination, indirect hemagglutination, and sperm immobilization tests on pre- and postvasectomy sera obtained at timed intervals of one to one hundred and two weeks indicated that significant sperm agglutinating, hemagglutinating, and immobilizing antibodies did not develop in these animals. Also, lymphocyte transformation studies showed that a significant cellular antibody response to sperm antigen(s) did not develop in vasectomized animals. Furthermore, sera from rhesus monkeys injected with autologous and homologous washed sperm in Freund's adjuvant failed to demonstrate a positive reaction in agglutination and immobilization tests. On the other hand, immunization of a female rhesus monkey with washed sperm in Freund's adjuvant produced high titer sperm agglutinating and immobilizing antibodies. Therefore, it has not been possible to repeat or contribute supporting data to literature reports concerning the presence of antibodies to sperm in vasectomized rhesus monkeys. It is further suggested that a number of antigens unrelated to sperm might react with sera obtained from vasectomized animals and lead to positive findings in sperm agglutination and immobilization tests. As a result, erroneous conclusions may be drawn about the development of antibodies specific for sperm in vasectomized rhesus monkeys. Definitive conclusions concerning the development of specific antibodies to sperm antigens after vasectomy will be possible only when sperm antigens have been isolated, purified, and chemically and immunologically characterized for use in serologic tests.     

Analysis of spermatozoa from the proximal vas deferens of vasectomized men

This study assessed the condition of spermatozoa from the proximal vas deferens of men after vasectomy. The fluids of both proximal vas deferens were collected from 67 vasectomized men by cannulating the vas deferens at the time of vasectomy reversal. Selected sperm parameters were analysed after incubation of the spermatozoa for 30 min at 37°C. Spera concentration in the proximal vas from vasectomized men (16 312 ± 21 496 million per ml, geometric mean: 7948 ± 398 million per ml) was significantly higher than that of fertile men and was maintained at a constant level independent of the duration of vas obstruction. The means of sperm motility (36.2 ± 26.2%), spermatozoa with normal morphology (50.7 ± 21.7%), sperm viability (53.0 ± 25.3%) and hypo-osmotic swelling test (HOS-test, 53.9 ± 21.7%) were statistically lower than the respective values for normal fertile men. There was no significant correlation between the duration of vas obstruction and the above semen parameters. In 46.4% of vas fluids all spermatozoa were immotile and this condition was more common after 3 years of vasectomy. Immotile spermatozoa in the proximal vas fluids at the time of vasectomy reversal may be an important factor for predicting semen quality and fertilizing ability after vasovasostomy. There were no significant differences in the results of sperm-cervical mucus penetration test (CMPT) between spermatozoa fiom vasectomized and fertile men. Antisperm antibodies on the surface of spermatozoa from the vas of vasectomized men were determined by the immunobead test (IBT; 78.6% for IgG, 32.1% for IgA) and sperm cervical mucus contact test (SCMC, 36.4%). The presence of antisperm antibodies on the spermatozoa from the vas of vasectomized men may explain, in part, the lower pregnancy rate after vasovasostomy. These parameters of spermatozoa from the proximal vas of vasectomized men may closely reflect those in the cauda epididymis after vasectomy.