Testicular subcutaneous allografting followed by immunosuppressive treatment promotes maintenance of spermatogonial cells in rainbow trout (Oncorhynchus mykiss)

Germ cell transplantation and testis graft represent promising biotechnologies that can be applied for the reproduction of commercial or endangered species. However, mechanisms of rejection from the host immune system might remove the transplanted donor cells/tissues and limit the surrogate production of gametes. In this work, we administered emulsion containing-immunosuppressants to verify whether they are capable to prevent immune rejection and promote survival of testis allografts in rainbow trout. In the first part of this study, we demonstrated in vitro that tacrolimus and cyclosporine were able to affect viability, inhibit leucocyte proliferation, and suppress il2 expression in vitro. In in vivo experiments, both doses of tacrolimus (0.5 and 1.5 mg/kg) and the lower dose of cyclosporine (20 mg/kg) significantly inhibited the expression of il2 in head kidney, three days post-injection. A higher dose of cyclosporine (40 mg/kg) was able to inhibit il2 expression for up to seven days post-injection. In the second part, testis allografts were conducted in fish treated weekly with emulsion containing-tacrolimus. Immunohistochemical, conventional histology, and qRT-PCR (vasa) analysis demonstrated the presence of spermatogonial cells by the fifth week, in animals treated with 0.5 mg/kg of tacrolimus similar as found in autografted group. In the group treated with the highest tacrolimus dose (1.5 mg/kg) and in the non-treated group (without immunosuppressant), no germ cells or their respective markers were detected. il2 expression in head kidney was also suppressed in grafted animals treated with tacrolimus compared to non-treated group. These results suggest that tacrolimus may be a promising immunosuppressant for testis allografts or germ cell transplantation in rainbow trout. Co-administration combining tacrolimus (at lower dose) with other immunosuppressive drugs for inhibiting other activation pathways of the immune system, as performed in human organ transplantation, could be an alternative approach to optimize the immunosuppressive effects in host organisms.

Role of Tissue-Specific Stem and Progenitor Cells in the Regeneration of the Pancreas and Testicular Tissue in Diabetic Disorders

Using the model of hypogonadism in C57Bl/6 male mice, we showed that injection of streptozotocin to newborn animals and high-fat diet induced serum IFN-γ and IL-17 elevation, glucose metabolism disturbances, insulin resistance, destructive changes of the Langerhans islets (deficit of PDX1⁺β cells), while the number of oligopotent β cell precursors (CD45^-TER119^-CD133⁺CD49f^low) increased. Diabetes played the role of an inducer of testicular tissue inflammation (pan-hemopoietic cell infiltration, increase of IL-2, IL-17, and IL-23 content) and reproductive system disturbances in mice (decrease in free testosterone concentration, suppression of spermatogenesis, and infertility). The development of hypogonadism was paralleled by an increase in the count of spermatogonial stem cells (CD117⁺CD29⁺CD90⁺), multipotent mesenchymal stromal cells (CD45^-CD31^-CD90⁺CD106⁺), hemangiogenesis precursors (CD45^-CD117⁺Flk1⁺), and epithelial cells (CD45^-CD31^-CD49f⁺CD326⁺).

NFLUENCE OF MAST CELLS ON REPARATIVE REGENERATION OF TISSUES WITH DIFFERENT DEGREE OF IMMUNOLOGICAL PRIVILEGES

It is assumed that tissues with different degree of imminological privileges have a number of distinctions in the processes of reparation. This may be associated with mast cells, which are found in all body tissues of an organism, secrete a wide range of biologically active substances and are important in the regulation of repair processes. This paper present the results of investigations of morphometric parameners and functional activity of mast cells in tissues with varying degrees of immune privilege (skin, testis). It has been shown that migration of must cells in the skin is observed early after the injury and followed by a slow increase of synthetic activity and index of degranulation of mastocytes within 30 days. Index of degranulation of mast cells in the testes increased immediately after the injury in the absence of their pronounced migration. Stabilizing membranes of mast cells using the drug ketotifen led to inhibition of the repair of the skin, which was manifested itself in the absence of increasing the thickness of dermis, epidermis, the number of fibroblasts and collagen fibers, and also in slowing down the formation of scar. At the same time, the inactivation of mast cells promoted reparative regeneration of testes as was indicated by increase in the number of normal spermatogonia which are proliferative pool for all subsequent stages of spermatogenesis, and by considerable decrease in the number of non-functioning tubules. Thus, the number and the functional sate of the mast cells have an impact on the course of reparative processes in tissues with varying degrees of immune privileges.

Mice spermatogonial stem cells transplantation induces macrophage migration into the seminiferous epithelium and lipid body formation: high-resolution light microscopy and ultrastructural studies

Transplantation of spermatogonial stem cells (SSCs), the male germline stem cells, in experimental animal models has been successfully used to study mechanisms involved in SSC self-renewal and to restore fertility. However, there are still many challenges associated with understanding the recipient immune response for SSCs use in clinical therapies. Here, we have undertaken a detailed structural study of macrophages elicited by SSCs transplantation in mice using both high-resolution light microscopy (HRLM) and transmission electron microscopy (TEM). We demonstrate that SSCs transplantation elicits a rapid and potent recruitment of macrophages into the seminiferous epithelium (SE). Infiltrating macrophages were derived from differentiation of peritubular monocyte-like cells into typical activated macrophages, which actively migrate through the SE, accumulate in the tubule lumen, and direct phagocytosis of differentiating germ cells and spermatozoa. Quantitative TEM analyses revealed increased formation of lipid bodies (LBs), organelles recognized as intracellular platforms for synthesis of inflammatory mediators and key markers of macrophage activation, within both infiltrating macrophages and Sertoli cells. LBs significantly increased in number and size in parallel to the augmented macrophage migration during different times post-transplantation. Our findings suggest that LBs may be involved with immunomodulatory mechanisms regulating the seminiferous tubule niche after SSC transplantation.

Expression of Aire and the early wave of apoptosis in spermatogenesis

Expression of the autoimmune regulator (Aire) protein in mice and humans is thought to be restricted to the medullary epithelial and monocyte-dendritic cells of the thymus. There it mediates expression and presentation of a large variety of proteins, including those that are peripheral organ-specific and are not expressed by other thymocytes. In this way, self-reactive T lymphocytes that would attack peripheral cells producing these proteins are confronted with the self-Ags and, as a consequence, are deleted. In this study, we show that Aire mRNA is also expressed in the testis--another tissue with promiscuous gene expression. Aire protein, however, is expressed only sporadically in spermatogonia and spermatocytes. Transcription of genes that are under Aire control in the thymus is unaffected by Aire in the testis. However, in mice with a disrupted Aire gene, the scheduled apoptotic wave of germ cells, which is necessary for normal mature spermatogenesis, is reduced, and sporadic apoptosis in adults is increased. Because Rag-1 deficiency does not abolish the effect, the adaptive immune system is not involved. We suggest that there is a link between the scheduled and sporadic apoptotic processes and propose that scheduled apoptosis provides a counterselection mechanism that keeps the germline stable.

[Isolation, purification and immunochemical characteristics of spermatogonia of rat]

OBJECTIVE

To explore the approach of isolation and purification of spermatogonia and its immunochemical characteristics.

METHODS

Compound enzymatic digestions were used to prepare germ cell suspensions of Sprague-Dawley rats aged 10 days, and velocity sedimentation and discontinuous Percoll density gradient centrifugation were used to isolate and purify the spermatogonia. Using c-kit and alpha(6)-integrin multiclone antibodies as markers respectively, the immunochemical characteristics of the spermatogonia in the testicular tissue were observed and the c-kit and alpha(6)-integrin expression rates of the purified cells were detected by flow cytometry.

RESULTS

The spermatogonia uniquely expressed c-kit and alpha(6)-Integrin in the testicular tissue. C-kit and alpha(6)-integrin were positively expressed in the purified cell suspensions. Using c-kit as the cell marker, the positive rate was 1.59% +/- 0.04% in the unpurified group, significantly lower than that of the purified group (68.33% +/- 2.45%, P < 0.01). Using alpha(6)-integrin as the cell marker, the positive rate of the unpurified group was 2.38% +/- 0.60%, significantly lower than that of the purified group (72.04% +/- 3.65%, P < 0.01). Trypan blue staining showed that the cell viability of the purified cell suspensions was more than 95%.

CONCLUSION

c-kit and alpha(6)-integrin can be used as the molecular markers of spermatogonium at special stage. Spermatogonia with high purity and viability can be obtained via the steps including digestions with enzymes, velocity sedimentation and discontinuous percoll density gradient centrifugation.

Significant IgG-immunoreactivity of the spermatogonia of the germ cell-depleted testis after busulfan treatment

Busulfan kills spermatogonia with the exception of a few that are attached to the basal membrane of the seminiferous epithelium. In mice, these remaining spermatogonia reacted strongly to a goat anti-mouse IgG antibody. Spermatogonia in untreated testes rarely showed the same reactivity. Testicular IgG levels are normally minimal but increase markedly, 4 weeks after busulfan treatment before peaking at week 6. Laser scanning cytometry analysis of control and busulfan-treated testicular cells showed busulfan treatment increased the frequency of cells that were positive for not only IgG (from 0.67+/-0.29 to 16.5+/-3.8%) but also for alpha6-integrin, beta1-integrin, GFR(-1 and/or Ret. Thus, an enrichment in putative male stem cells correlates with appearance of IgG expression. Confocal microscopy revealed busulfan-treated cells contained both IgG and GFRalpha-1, and that the initial surface IgG became intracellular in the weeks following busulfan treatment. The basement membranes of the seminiferous tubules were compromised by busulfan treatment as the mRNA expression profiles of various adhesion molecules in the basement membranes were altered and electron microscopy revealed severe damage. Serum IgG levels increased in a manner corresponding with the increase in testicular IgG levels. Thus, it appears that in the busulfan-treated testis, small breaches of the blood-testis barrier leak IgG that is then taken up by a significant number of spermatogonia. When the busulfan-resistant germ cells were transferred into recipient germ cell-depleted testes, they settled and repopulated the recipient testes. Thus, the IgG-bearing cells observed after busulfan treatment may be putative spermatogonial stem cells.

Endocrine roles of D-aspartic acid in the testis of lizard Podarcis s. sicula

In the lizard Podarcis s. sicula, a substantial amount of D-aspartate (D-Asp) is endogenous to the testis and shows cyclic changes of activity connected with sex hormone profiles during the annual reproductive phases. Testicular D-Asp content shows a direct correlation with testosterone titres and a reverse correlation with 17beta-estradiol titres. In vivo experiments, consisting of i.p. injections of 2.0 micromol/g body weight of D-Asp or other amino acids, in lizards collected during the three main phases of the reproductive cycle (pre-reproductive, reproductive and post-reproductive period), revealed that the testis can specifically take up and accumulate D-Asp alone. Moreover, this amino acid influences the synthesis of testosterone and 17beta-estradiol in all phases of the cycle. This phenomenon is particularly evident during the pre- and post-reproductive period, when endogenous testosterone levels observed in both testis and plasma were the lowest and 17beta-estradiol concentrations were the highest. D-Asp rapidly induces a fall in 17beta-estradiol and a rise in testosterone at 3 h post-injection in the testis and at 6 h post-injection in the blood. In vitro experiments show that testicular tissue converted L-Asp into D-Asp through an aspartate racemase. D-Asp synthesis was measured in all phases of the cycle, but was significantly higher during the reproductive period with a peak at pH 6.0. The exogenous D-Asp also induces a significant increase in the mitotic activity of the testis at 3 h (P < 0.05) and at 6 h (P < 0.01). Induction of spermatogenesis by D-Asp is recognized by an intense immunoreactivity of the germinal epithelium (spermatogonia and spermatids) for proliferation cell nuclear antigen (PCNA). The effects of D-Asp on the testis appear to be specific since they were not seen in lizards injected with other D- or L-forms of amino acids with known excitatory effects on neurosecretion. Our results suggest a regulatory role for D-Asp in the steroido-genesis and spermatogenesis of the testis of the lizard Podarcis s. sicula.

Spermatogonial stem cells share some, but not all, phenotypic and functional characteristics with other stem cells

Spermatogonial stem cells (SSCs) are responsible for maintaining spermatogenesis throughout life in the male by continuous production of daughter cells that differentiate into spermatozoa. However, no unique phenotypic markers to identify SSCs have been described. In this study, the SSC surface phenotype was characterized by using flow cytometric cell sorting in conjunction with a transplantation functional assay for SSCs. Highly enriched stem cell activity was found in the MHC class I (MHC-I)-Thy-1+c-kit- cell fraction of the mouse cryptorchid testis. There was little or no stem cell activity in any other fraction. The antigenic phenotype of the MHC-I-Thy-1+c-kit- SSCs was alpha6-integrin+CD24+alphavintegrin-Sca-1-CD34-. Subsequently, testis side population (SP) cells, which are defined by a Hoechst dye efflux assay, were identified. Their surface phenotype was found to be MHC-I+Thy-1-Sca-1+, and the transplantation assay demonstrated that the testis SP and SSCs are distinct populations. In several other tissues, the SP has been shown to contain stem cells, but we found that this characteristic does not define SSCs. The identification of a surface phenotype that allows production of a highly enriched SSC population will facilitate functional and genomic studies and enable further comparison with other stem cells.

Over expression of interleukin-1alpha, interleukin-1beta and interleukin-1 receptor antagonist in testicular tissues from sexually immature mice as compared to adult mice

The levels of IL-1alpha, IL-1beta and IL-1Ra were higher in homogenates of testicular tissue from sexually immature than those from mature mice. Immunohistochemical staining of testicular tissues from sexually immature and adult mice show that differentiated germ cells express higher levels of IL-1alpha compared to Sertoli cells and Leydig cells/interstitial cells. Peritubular cells of sexually immature and adult mice did not express IL-1alpha. Testicular tissue cells of adult mice showed high levels of expression of IL-1beta, mainly in the cytoplasm and nucleus of the spermatogonia and in spermatocytes. Sertoli cells and Leydig/interstitial cells were also highly stained for IL-1beta. However, peritubular cells did not express IL-1beta. On the other hand, testicular tissue cells from sexually immature mice, showed high levels of IL-1beta, mainly in spermatocytes. Spermatogonia showed low levels of IL-1beta expression. Also, high levels of IL-1beta expression were detected in Leydig/interstitial cells. Peritubular cells clearly showed IL-1beta expression. Testicular tissue cells from adult mice, showed IL-1Ra expression in spermatogonia, Sertoli and Leydig/interstitial cells. IL-1Ra expression was clearly present in the Golgi apparatus of spermatogonia and Sertoli cells. However, peritubular cells did not show IL-1Ra expression. Testicular tissue cells from sexually immature mice, also showed high levels of IL-1Ra expression mainly in the cytoplasm and nucleus of the spermatogonia and Sertoli cells. In addition, Leydig/interstitial cells and peritubular cells also expressed IL-1Ra. Our results demonstrate, for the first time, the expression of IL-1beta in germ and Sertoli cells, and IL-1Ra in Leydig/interstitial cells of testicular tissues from adult and sexually immature mice, under in vivo conditions. In addition, the relative elevated levels of the IL-1 system in the testis of immature mice compared to mature mice may indicate its involvement in the spermatogenesis.

The closely related POU family transcription factors Brn-3a and Brn-3b are expressed in distinct cell types in the testis

Although the Brn-3a and Brn-3b POU family transcription factors were originally identified in neuronal cells, their expression in some non neuronal cell types has previously been reported. Here we report that Brn-3a and Brn-3b are also expressed in the testis with expression of each factor being observed at distinct stages of germ cell development. Thus, Brn-3a is expressed in spermatogonia whereas Brn-3b expression is observed in post-meiotic spermatids. In agreement with this, Brn-3a expression is detectable much earlier than that of Brn-3b in testes derived from sexually immature postnatal animals. Similarly, Brn-3b expression is absent in knock out mice lacking a functional CREM transcription factor in which the later stages of germ cell development do not occur, whereas Brn-3a expression is observed at similar levels in the testes of these knock out mice. Interestingly, the cellular pattern of Brn-3a expression during germ cell development coincides with that of the BRCA-1 anti-oncogene. Consistent with the possibility that Brn-3a may regulate expression of BRCA-1 in the testis, we have shown that Brn-3a can strongly activate the BRCA-1 promoter in co-transfection experiments whereas Brn-3b does not have this effect. Hence, as observed in neuronal cells, Brn-3a and Brn-3b may play distinct and important functional roles in the regulation of gene expression during germ cell development.

Expression and regulation of the CXC-chemokines, GRO/KC and IP-10/mob-1 in rat seminiferous tubules

Testicular inflammation is classically observed in the pathogenesis of viral and bacterial infection or tumoral invasion. In these situations, leukocyte infiltration is generally encountered. GRO/KC (growth-related oncogene) and IP-10/mob-1 (IFN-gamma-inducible protein) are two CXC-chemokines which attract neutrophils and activated T lymphocytes, respectively, have been studied for their ability to participate to testicular inflammation (orchitis). In the present work, using Northern blot and immunocytochemistry, we aimed to investigate whether GRO/KC and IP-10/mob-1 are produced within the seminiferous tubules of the testis and if these chemokines are induced by a number of pro-inflammatory cytokines and lipopolysaccharides (LPS). Our results show that GRO/KC and IP-10/mob-1 mRNAs were never found in germ cells, whether they were stimulated or not. In contrast, GRO/KC mRNA was expressed by isolated peritubular cells when stimulated by interleukin-1 alpha and beta (IL-1 alpha and IL-1 beta) or LPS and to a lesser extent by tumor necrosis factor-alpha (TNF-alpha) and by Sertoli cells when the latter were stimulated by rIL-alpha and rIL-1 beta and to a lesser extent by TNF-alpha and LPS. Moreover, IP10/mob-1 transcripts were strongly induced in peritubular cells by interferon-alpha (IFN-alpha) and IFN-gamma, whereas, in isolated Sertoli cells, INF-alpha and TNF-alpha were the only potent inducers. The kinetics of GRO/KC and IP-10/mob-1 mRNA expression by peritubular and Sertoli cells (significant stimulation as early as 1 hour and 4 hours post-exposure to the stimuli, respectively) are compatible with the hypothesis of a rapid mobilisation of these cells in an inflammatory process. Moreover, the dose-dependent effects of pro-inflammatory cytokines to induce a chemokine response were compatible with a high sensitivity of peritubular and Sertoli cells in orchitis. In conclusion, this present study shows that 2 CXC-chemokines, GRO/KC and IP10/mob-1, are produced by testicular somatic cells of seminiferous tubules, strongly indicating a likely role of these chemokines in the accumulation of neutrophils and T lymphocytes during orchitis of various origins.

Molecular cloning, expression and characterization of the rat analogue of human membrane cofactor protein (MCP/CD46)

In humans, host cells are protected from homologous complement by membrane proteins encoded in the regulators of complement activation (RCA) gene cluster. These include complement receptor 1 (CR1), decay-accelerating factor (DAF, CD55) and membrane cofactor protein (MCP, CD46). In mouse and rat a single membrane inhibitor, Crry, appeared to perform the functions of both DAF and MCP and was proposed to be the functional analogue of both. Recently, however, murine homologues of DAF and MCP have been identified, prompting a search for the rat counterparts. We have described the identification of rat DAF and here describe the cloning of rat MCP from cDNA and genomic libraries, using a probe based on the mouse MCP cDNA sequence. The domain structure for rat MCP was identical to that of mouse MCP with four short consensus repeats (SCRs) followed by a STP domain, transmembrane segment and cytoplasmic tail. Overall identity of rat and mouse MCP was 77% at the amino acid level and 88% at the nucleotide level. Northern blot analysis from a range of tissues indicated that high-level expression was limited to the testis, although expression in other tissues was detected using reverse transcription-polymerase chain reaction. Rat MCP mRNA localized to Sertoli cells and spermatogonia in seminiferous tubules by in situ hybridization, but was absent in mature sperm. In cofactor assays utilizing human factor I, a recombinant soluble form of rat MCP catalysed cleavage of human C3ma.

beta1- and alpha6-integrin are surface markers on mouse spermatogonial stem cells

Although spermatogenesis is essential for reproduction, little is known about spermatogonial stem cells. These cells provide the basis for spermatogenesis throughout adult life by undergoing self-renewal and by providing progeny that differentiate into spermatozoa. A major impediment to our understanding of the biology of these stem cells is the inability to distinguish them from spermatogonia that are committed to differentiation. We made use of the known association of stem cells with basement membranes and our spermatogonial transplantation assay system to identify specific molecular markers on the stem cell surface. Selection of mouse testis cells with anti-beta1- or anti-alpha6-integrin antibody, but not anti-c-kit antibody, produced cell populations with a significantly enhanced ability to colonize recipient testes and generate donor cell-derived spermatogenesis. We demonstrate spermatogonial stem cell-associated antigens by using an assay system based on biological function. Furthermore, the presence of surface integrins on spermatogonial stem cells suggests that these cells share elements of a common molecular machinery with stem cells in other tissues.

A novel stage-specific antigen is expressed only in early stages of spermatogonia in Japanese eel, Anguilla japonica testis

We produced an antibody that recognized only early stages of spermatogonia in Japanese eel testis. This antibody (anti-spermatogonia-specific antigen-1, anti-SGSA-1) recognized a band of about 38 kDa in Western blot analysis of extracts from eel testis. This antigen was observed by immunohistochemistry only in type-A and early type-B spermatogonia and could not be seen in the late type-B spermatogonia, which appeared after the initiation of spermatogenesis by a single injection of human chorionic gonadotropin. Immunoreactive SGSA-1 was absent in spermatocytes, spermatids, spermatozoa, Sertoli cells, and interstitial Leydig cells. Similarly, this antigen was also detected only in type-A/primary spermatogonia in the testes of two species of teleosts, medaka (Oryzias latipes) and tilapia (Oreochromis niloticus), as well as a toad (Xenopus laevis). These results imply that the disappearance of SGSA-1 in late type-B/secondary spermatogonia is a critical step in the progression of spermatogenesis, and indicate that anti-SGSA-1 is a useful marker for analysis of the molecular mechanism controlling the differentiation of spermatogonia in lower vertebrates.

The expression of mouse gene P1A in testis does not prevent safe induction of cytolytic T cells against a P1A-encoded tumor antigen

Tumor antigen P815AB is recognized by cytolytic T lymphocytes (CTL) on mouse mastocytoma P815. This antigen is encoded by P1A, a gene activated in several tumors but silent in normal tissues except for testis and placenta. Notwithstanding the expression of P1A in testis, we found that male mice mounted P815AB-specific CTL responses as efficiently as females. The responding males remained fertile and no autoimmune lesions were observed in their testes. By immunohistochemistry with a rabbit antiserum directed against the P1A protein, we identified spermatogonia as the testicular cells expressing P1A. The absence of MHC class-I molecules on spermatogonia could be one of the mechanisms of protection against testicular autoimmunity, as the antigenic peptide should not be displayed at the cell surface. Human genes MAGE, BAGE and GAGE, which also code for tumor antigens recognized by autologous CTL, are not expressed in normal tissues other than testis. The results obtained in mice with antigen P815AB suggest that immunization of human males with such antigens will not generate autoimmune side-effects. Although P1A is strongly expressed in placenta, we also found that gestation did not prevent generation of CTL responses against antigen P815AB, and that such CTL responses did not affect gestation outcome. We identified labyrinthine trophoblasts as the placental cells expressing P1A. Again, the absence of MHC class-I molecules on these cells provides a plausible explanation for placental protection, although other mechanisms may also play a role.

A monoclonal antibody that specifically reacts with human embryonal carcinomas, spermatogonia and oocytes is able to induce human EC cell death

We developed a mouse monoclonal antibody, 6E2 (IgG3), against a human embryonal carcinoma (EC) cell line, NCR-G3, that possesses totipotent differentiation capabilities. Culturing human EC cells in the presence of 6E2 causes their death. It has been shown that 6E2 kills EC cells dose dependently. In immunohistochemical examination with normal human germ cells, 6E2 reacted specifically with spermatogonia and oocytes. Among human germ cell tumor tissues on aceton-fixed frozen sections, 6E2 reacted with embryonal carcinomas, seminomas and dysgerminomas, but it did not react with choriocarcinomas or with yolk sac tumors. Consistently, in flow cytometric analysis of cultured human germ cell tumor cell lines, 6E2 reacted exclusively with EC cells including NCR-G3 cells. It was revealed, by preserving its antigenicity after treatment with periodic acid and tunicamycin and by radiolabeling cells followed by immunoprecipitation, that the molecule defined by 6E2 is a cell surface protein having a molecular weight of approximately 80 kDa. These data illustrate that the molecule defined by 6E2 links human germ cell tumors, especially embryonal carcinoma, seminoma and dysgerminoma, to their normal counterparts and that it may play a role in survival and proliferation of human EC cells.

[Early or late orchidopexy? An evaluation of germ cell proliferation by PCNA immune expression]

A immunocytochemical study for detection of proliferating cell nuclear antigen (PCNA) in order to quantify the number of PCNA-positive spermatogonia, and cytophotometric determination of spermatogonial DNA were performed in cryptorchid and control testes. The number of PCNA-positive spermatogonia, and the average DNA content of spermatogonia in the cryptorchid testes were altered from first years of age. These precocious spermatogonial alterations suggest that the early surgical testicular descent doesn't prevent lesions of germ cells.

Phenotypic changes in germ cells during gonadal development of the common carp (Cyprinus carpio). An immunohistochemical study with anti-carp spermatogonia monoclonal antibodies

A procedure is described in which large early spermatogonia were isolated from carp testes and purified from an initial 4-5% recovery up to 60-70% using equilibrium density centrifugation on a continuous Percoll gradient. Mice were immunized with the spermatogonia via the intrasplenic route. Six hybridoma cultures, producing monoclonal antibodies (MAbs) reacting selectively with germ cells, were selected and further analysed. Reactivity with five of these MAbs was observed on primordial germ cells (PGCs) in the developing indifferent gonads at the onset of proliferation, i.e. the age of 7 weeks. One MAb, encoded WCG6, appeared to define a new surface marker on PGCs being gradually expressed on the surface membrane between the age of 2 and 4 weeks, concomitantly with an increase in size of these mitotically silent cells. The reactivity of germ cells with five of the MAbs disappeared completely (WCG 7, 12, 15, 21) or nearly completely (WCG 6) during spermatogenesis, providing a striking difference from patterns obtained with MAbs raised previously against carp spermatozoa. Differences between male and female germ cells were not observed with the WCG-MAbs during gonad development, indicating that a common set of surface antigens is shared between germ cells of both sexes up to and including spermatogonia and oogonia.

Analysis of various antigens in golden hamster testis by monoclonal antibodies

A total of 38 hybridomas producing monoclonal antibodies (mAbs) was established by immunizing BALB/c mice with extracts of the golden hamster testis. Six mAbs stained the acrosome of developing spermatids by immunofluorescence. Two mAbs (1A11 and 4D8) reacted with spermatid components other than acrosome. The mAbs 1C9 and 4D3 recognized a 103 kilodalton (kDa) protein on immunoblots, and were reactive to spermatocytes and early spermatids, but not to late spermatids and spermatozoa. This finding suggests that the protein functions for meiosis or early spermiogenesis. Four mAbs (3G2, 2E5, 2G3, and 3F10) stained all stages of spermatogenic cells. The remaining 24 mAbs showed a positive reaction to the basement membrane of the seminiferous tubule. Two of them, 3D6 and 3E5, recognized approximately 150 kDa major proteins, indicating that the antigen is an extracellular matrix.

Is there a high rate of mitotic recombination between the loci encoding immunoglobulin VH and CH regions in gonial cells?

Rabbit sera from approximately 6000 offspring of matings informative for recombination at the immunoglobulin (Ig) heavy chain locus were tested with allotype antisera by double diffusion in gel. Seven recombinants were found, R1K-R7K, and in every case the recombinational event had taken place in the male parent. Two single males each fathered two recombinant offspring: R2K, R4K and R5K, R6K. Four further recombinants, reported from other laboratories as well as two new, as yet not fully documented recombinants in our laboratory, also occurred in the male parent. The recombinational events either separated the a locus which encodes the VH region of Ig, from the loci encoding its CH region or separated a-ms from the remaining linked loci d-e-f-g. The recombination frequency is 7/6142, approximately 0.1%. Our findings suggests that the recombinations took place in mitotic divisions during spermatogenesis. This work is the first evidence of gonial crossing-over in a mammal.

Monoclonal antibodies to human germ cell tumors from "routine" paraffin-embedded pathological specimens

We have established a method for monoclonal antibody (MoAb) preparation from routine paraffin-embedded tissue of human seminoma as an immunogen. Three 40-microns thick sections were deparaffinized and rehydrated. An eight-week-old BALB/c mouse was immunized intraperitoneally with this extract, which showed no detectable protein bands on sodium laurylsulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Five monoclonal antibodies (MoAbs) with different characteristics were obtained; one reacted with the nucleus, two with the cytoplasm, and two with the cytoplasmic membrane. One of the MoAbs 5G9 reacted with spermatogonia in normal human tissues and with seminoma, embryonal carcinoma and choriocarcinoma in the testicular tumors.

Surface location and stage-specificity of differentiation antigens on germ cells in the common carp (Cyprinus carpio), as revealed with monoclonal antibodies and immunogold staining

During development of juvenile and young adult carp (Cyprinus carpio, L., Teleostei) three differentiation stages were distinguished in the testis: the prespermatogenic, the early spermatogenic and the advanced spermatogenic testis. Carp testis tissue of these stages was dissociated by enzymatic digestion and viable testis cells with well preserved morphological features were obtained. The surface location and stage-specificity of differentiation antigens on these germ cells was investigated using monoclonal antibodies (MAbs) raised against carp spermatozoa. Binding of MAbs to cells was visualized with immunofluorescence as well as in the immunogold staining assay. Both methods revealed that antigenic determinants defined by seven MAbs were located on the outer surface of testis cells. Four MAbs, i.e. WCS 3, 17, 28 and 29, reacted with germ cells from both pre-spermatogenic testes (WCS 28 weakly) and spermatogenic testes. The antigenic determinants defined by three other MAbs, i.e. WCS 7, 11 and 12, appeared only after the onset of spermatogenesis. In the immunogold staining assay a post-fixation and nuclear staining procedure was developed which allowed identification of isolated germ cells, revealing clearly, for all seven MAbs, that the determinants were expressed on germ cells but not on somatic cells and, for WCS 7, 11 and 12 only, that the determinants first appeared on small spermatogonia prior to meiosis. A survey of the immunogold assay on the binding of the seven MAbs with isolated germ cells from ovaries, is included.

The distribution of sex-specific (H-Y) antigens within the seminiferous tubules of the testis: an immunohistochemical study

The cellular distribution of H-Y antigen within the seminiferous tubules of testes from both 20-day-old and adult rats has been examined immunohistochemically. Large amounts of diffuse-staining material surrounding the germ cells were observed within the tubules of 20-day-old rats while the germ cells appeared to have little H-Y positive material on them. In the sexually mature rat, the seminiferous tubules contained cells at various stages of development. Peroxidase staining was evident on many, but not all of these cells. On spermatids and spermatozoa with cytoplasmic droplets attached, peroxidase staining appeared to be present in only a proportion of these cells.

Purification and characterization of a proline-rich secretory protein that is a precursor to a structural protein of an insect spermatophore

The spermatophore or sperm sac of Tenebrio molitor (yellow mealworm beetle) is an acellular structure composed mostly of structural proteins, termed spermatophorins. The proteins are derived from the bean-shaped accessory reproductive glands of the male and are assembled into the multilayered structure within the ejaculatory duct. Homogenates of the secretory plug from this gland were used as immunogens for the production of monoclonal antibodies, including one identified as PL 21.1 which recognizes an antigen in the gland and the spermatophore. With the aid of gel filtration and immunoaffinity chromatography with a PL 21.1, we isolated a glandular secretory protein that is a precursor to a spermatophorin with similar electrophoretic mobility. On native polyacrylamide gels, the antigen from gland homogenates has an apparent molecular mass of 370 kDa. On sodium dodecyl sulfate gels, the antigen from the gland and that from the spermatophore have apparent molecular masses of 23 kDa. According to immunoblots of sodium dodecyl sulfate gels, the 23-kDa glandular antigen is organ-specific and adult-specific. By immunocytochemistry with PL 21.1, we found the antigens to be restricted to secretory vesicles of only one cell type in the gland and to a discrete layer in the outer wall of the spermatophore. The 23-kDa secretory antigen is distinguished by being high in glutamic acid/glutamine (15.4%) and in proline (25.2%).

The occurrence of serological H-Y antigen (Sxs antigen) in the diandric protogynous wrasse, Coris julis (L.) (Labridae, Teleostei)

The serological sex-specific (Sxs) antigen (previously called 'H-Y antigen') has been shown, in various vertebrate species ranging from fish to mammals, to be characteristic of the heterogametic sex. We studied a protogynous hermaphrodite, Coris julis, in order to examine whether the change of a female to a secondary male also involves a change in the Sxs-antigen phenotype. The (homogametic) females of this species were found to be Sxs negative, while both primary and secondary males were Sxs positive. This was true not only for gonads but also for nongonadal tissues. The administration of androgen to females is known to cause sex inversion in this species; we were able to demonstrate this again at the histological level, and found that androgen results in a Sxs positive phenotype in all tissues studied (gonads, spleen, muscle). We propose that androgen is responsible, directly or indirectly, for the occurrence of the Sxs antigen.

Analysis of the autoimmune response in an 'in situ' carcinoma of the testis

Immune response in a patient with an in-situ seminoma of the testis was studied. Immunohistochemical examination of the testicular biopsy demonstrated remarkable intracellular and membraneous accumulation of IgG antibodies in the atypical spermatogonia. Using FITC-conjugated Concanavalin A, an abnormally high binding of Concanavalin A was detected in the transformed cells. Circulating antibodies directed against an antigenic determinant (60 kD) which is expressed on normal human spermatozoa and lymphocytes were found only in the patient's serum and not in 500 control sera. The role and possible diagnostic value of this autoimmune reactivity in testicular malignancies are discussed.

Ordered flow of secretion from accessory glands to specific layers of the spermatophore of mealworm beetles: demonstration with a monoclonal antibody

Monoclonal antibodies were produced against the secretory product of the bean-shaped accessory gland (BAG) of male mealworm beetles (Tenebrio molitor). Antibodies from one clone (PL 6.3) recognized a 9,600 dalton protein with a pI of 6.6 which was found in homogenates of the BAG. The PL 6.3 antigen was first detected on Western blots of BAG proteins from 2-day adults, and amounts increased for the next 6 days until reproductive maturation was achieved. The antibody also recognized a polypeptide with a molecular weight (mw) of about 5,000 daltons which we believe to be derived from the larger 9,600 dalton antigen. There are eight types of secretory cells in the BAG. By using light microscopic immunohistochemistry, we localized the antigens recognized by PL 6.3 in cell type 7 (intense staining) and cell type 5 (weak staining). Results from electron microscopic immunocytochemistry showed that antigen PL 6.3 was concentrated in the secretory granules characteristic of each of these two cell types and was absent in all other cell types. PL 6.3 antigens were traced from the BAG into its secretory product and then into the prespermatophoric mass in the ejaculatory duct. The antigen was not randomly mixed with other secretory products of the accessory glands. As it flowed from the BAG and into the ejaculatory duct, it remained in a coherent, precisely localized mass. Within the definitive spermatophore, the PL 6.3 antigen was concentrated in discrete layers of material that line the lumen.

Identification and partial characterization of a nucleolar antigen with a molecular weight of 145,000 found in a broad range of human cancers

Previous studies in our laboratory have indicated the presence of nucleolar antigens in tumors which were not detected in normal tissues. Some of the polyclonal antisera produced in these studies were shown to identify a Mr, 145,000 nucleolar antigen on immunoblots of tumor nucleoli but not in normal human liver nucleoli. A monoclonal antibody to a Mr 145,000 nucleolar protein (p145) was produced by immunization of mice with a nucleolar extract of HeLa cells which is enriched with this antigen. The monoclonal antibody showed bright nucleolar immunofluorescence localization in a broad range of human tumors including cancers of the gastrointestinal tract, genitourinary tract, lung, liver, muscle, cartilage, and blood. The p145 nucleolar antigen was not detected in most normal human tissues or in benign tumors, with only weak nucleolar staining observed in spermatogonia of the testes and in ductal regions of some hypertrophied prostates. Nucleolar antigen p145 was extracted from HeLa cell nucleoli by homogenization in a 0.01 M Tris buffer containing 0.2% deoxycholate. On sucrose density gradient centrifugation, the antigen remained sedimented with the nucleolar ribonucleoprotein fraction. Nucleolar antigen p145 was released from ribonucleoproteins following treatment with 4 M guanidinium hydrochloride or RNase. Peptide mapping of nucleolar antigen p145 showed that it was distinct from other known nucleolar antigens. Although it remains to be determined if the p145 antigen plays a role in cell transformation, maintenance of the malignant phenotype, or in cell division, it may have value as a tumor marker or as a therapeutic target.

Identification and immunochemical characterization of spermatogenic cell surface antigens that appear during early meiotic prophase

Three spermatogenic cell populations isolated from prepuberal mice--type B spermatogonia, preleptotene spermatocytes, and leptotene/zygotene spermatocytes--were used to elicit distinct polyclonal antisera. Surface binding specificities were determined for purified IgGs by indirect immunofluorescence and rosette assays on live cells. Binding activities were assayed both before and after absorptions with a variety of somatic and spermatogenic cells. Each of these antisera binds to surface antigens that are present on germ cells throughout spermatogenesis and are not shared by splenocytes, thymocytes, and erythrocytes. Only the antiserum raised against leptotene and zygotene spermatocytes (ALZ) recognizes a stage-specific subset of surface determinants. After appropriate absorptions, ALZ binds to the surface of early pachytene spermatocytes and germ cells at subsequent stages of differentiation, including vas deferens spermatozoa. Antigens which react with this absorbed IgG are not detected on the surface of spermatogonia or meiotic cells prior to pachynema, including leptotene and zygotene spermatocytes. The observed binding specificities may result from the synthesis of one or more surface molecules during the early meiotic stages, followed by delayed insertion into the plasma membrane during the pachytene stage of meiotic prophase. Stage-specific antigens recognized by ALZ, including both protein and probably lipid, have been localized immunochemically on nitrocellulose blots from one-dimensional SDS gels. A dithiothreitol-sensitive constituent (Mr approximately 39,000) recognized by ALZ has been identified as the major protein determinant present in early meiotic cells but absent in 8-day-old seminiferous cell suspensions containing spermatogonia and Sertoli cells. This determinant is present in populations of preleptotene, leptotene/zygotene, and early pachytene spermatocytes isolated from 17-day-old animals, an observation consistent with the hypothesis of delayed insertion into the plasma membrane.

Immune complex orchitis in infertile men. Immunoelectron microscopy of abnormal basement membrane structures

Testicular biopsies from 30 patients with fertility disorders were investigated by peroxidase-labeled antibodies against IgG and C3 at an ultrastructural level. Three types of abnormal basement membrane structures (ABMS) proved to be positive. Immune-type deposits (ABMS type 2), ABMS with vesicular particles (ABMS type 4), and those with membranous structures (ABMS type 5) stained positively for IgG and C3. In 21 cases ABMS were positive for at least one of the antisera. Two additional cases showed a linear reaction for IgG and C3 in the basement membrane. According to the number and size of positive ABMS, the cases were divided into three groups. Group I contained 10 cases with extensive ABMS types 2, 4, and 5 positive for IgG and C3 and two cases with linear positivity. At light microscopy, the changes varied from light to severe tubular atrophy. In these latter cases ABMS types 4 and 5 predominated, whereas in the light and focal tubular lesions ABMS type 2 did. In group II, eight cases revealed few and small ABMS positive by immunoelectron microscopy and no more than slight tubular changes at light microscopy. In group III, minimal or no ABMS were present, but in three cases mast cells were numerous in the interstitial tissue. The demonstration of immune deposits in the basement membrane of seminiferous tubules is interpreted to be the result of an antibody-mediated damage to the germinal epithelium leading to tubular atrophy. In one case obstruction of the sperm ducts and in another torsion of the testis are incriminated as events triggering the autoimmune process. Linear staining of the basement membrane for IgG and C3 in two cases suggests the development of antibasement membrane orchitis.

Expression of histoincompatibility antigens during spermatogenesis in the rat

The expression of the AgB-SB and -LD (Ia-like) antigens on spermatogenic cells has been investigated by using a protein A-containing Staphylococcus Cowan I rosetting assay. The results show that the Ia-like antigens are present on all spermatogenic cells although the relative expression seems to decrease slightly concomitant with the differentiation. The AgB-SD antigens are detected on spermatogenia, leptotene, and zygotene spermatocytes but not on later developmental stages.

Induction of tolerance in vitro by autologous murine testicular cells

We have investigated the regulation of self tolerance in mice by examining lymphocyte reactivity in vitro against two subpopulations of autologous testicular cells: germ cells that were derived from the seminiferous tubules, and interstitial somatic cells. In the presence of germ cells, lymphocyte proliferation was strongly reduced. In contrast, somatic interstitial cells stimulated lymphocyte proliferation. In both cases, reactive lymphocytes were mostly T cells. Suppressor T cells activated by autologous germ cells were nonspecific and capable of inhibiting lymphocyte proliferation against autologous and allogeneic somatic testicular cells as well as against allogeneic spleen cells. Suppression was abrogated after treatment of the responder lymphocytes with anti-Ly-2.2 serum plus complement. Lymphocyte proliferation by autologous interstitial cells was considerably reduced, but not completely abolished, by complement-dependent lysis with anti-Thy-1.2 serum. This may indicate the participation in proliferation of a lymphoid cell population other than T cells.

Studies on H-Y antigen in different cell fractions of the testis during pubescence: immature germ cells are H-Y antigen negative

Various cell types of the rat testis during pubescence, including germ, Sertoli, and Leydig cells, were partially enriched. The fractions were tested for the presence, binding, and secretion of H-Y antigen. The main results are: Immature germ cells are H-Y antigen-negative until the late diploid stages, and late primary spermatocytes or spermatids become positive; the somatic cells of the gonad are positive at all ages examined (18 days old to adulthood). Secretion of H-Y antigen is restricted to the Sertoli cell fraction. Binding of externally supplied antigen takes place on Leydig cells; the Sertoli cell surface will be saturated because of active secretion; there is no binding to germ cells. Thus, immature germ cells seem to be the only H-Y antigen-negative cells of the male organism, and the Sertoli cells seem to be the only ones to secrete H-Y antigen.

T-cell-mediated cytotoxic immune responses to F9 teratocarcinoma cells: cytolytic effector T cells lyse H-2-negative F9 cells and syngeneic spermatogonia

Murine thymus derived (T) lymphocytes primed in vivo to mouse 129 (H-2bc) derived H-2-negative F9 embryonal carcinoma cells and rechallenged in vitro with X-irradiated F9 stimulator cells differentiated into anti-F9 cell immune cytotoxic T lymphocytes (CTL). Using CBA mouse derived splenic responder T cells, F9 stimulator cells triggered a primary cytotoxic anti-F9 response. The CTL generated lysed the F9 antigen-positive target cells F9. PCC3 and PCC4, but not the F9 antigen-negative mouse 129 derived PYS tumor cells, nor LPS induced H-2bc blast cells. Mouse 129 anti-F9 cell antisera but not H-2k anti-H-2bc antisera blocked the lytic interaction with F9 target cells. Similarily unlabeled F9 cells but not H-2bc blast cells inhibited the anti-F9 cell cytotoxicity H-2k anti-F9 cell immune CTL were found to be cytotoxic for syngeneic spermatogonia, known to express the F9 antigen. The results suggest not only that CTL can recognize and lyse H-2-negative target cells, but also that CTL precursors can be sensitized against H-2-negative stimulator cells. From the data available it may be inferred that anti-F9 Cell immune CTL recognize the F9 antigen, known to be linked with the T/t locus. Since anti-F9 cell immune CTL lyse syngeneic spermatogonia, the system may be useful to analyze in vitro the induction and effector phase of a T-cell-mediated cytotoxic autoimmune orchitis.

Temporal expression of membrane antigens during mouse spermatogenesis

The temporal expression of cell surface antigens during mammalian spermatogenesis has been investigated using isolated populations of mouse germ cells. Spermatogenic cells at advanced stages of differentiation, including pachytene primary spermatocytes, round spermatids, and residual bodies of Regaud and mature spermatozoa, contain common antigenic membrane components which are not detected before the pachytene stage of the first meiotic prophase. These surface constituents are not detected on isolated populations of primitive type A spermatogonia, type A spermatogonia, type B spermatogonia, preleptotene primary spermatocytes, or leptotene and zygotene primary spermatocytes. These results have been demonstrated by immunofluorescence microscopy, by complement-mediated cytotoxicity, and by quantitative measurements of immunoglobulin (Ig) receptors on the plasma membrane of all cell populations examined. The cell surface antigens detected on germ cells are not found on mouse thymocytes, erythrocytes, or peripheral blood lymphocytes as determined by immunofluorescence and by cytotoxicity assays. Furthermore, absorption of antisera with kidney and liver tissue does not reduce the reactivity of the antibody preparations with spermatogenic cells, indicating that these antigenic determinants are specific to germ cells. This represents the first direct evidence for the ordered temporal appearance of plasma membrane antigens specific to particular classes of mouse spermatogenic cells. It appears that at late meiotic prophase, coincident with the production of pachytene primary spermatocytes, a variety of new components are inserted into the surface membranes of developing germ cells. The further identification and biochemical characterization of these constituents should facilitate an understanding of mammalian spermatogenesis at the molecular level.