Passive immunization with anti-laminin immunoglobulin G modifies the integrity of the seminiferous epithelium and induces arrest of spermatogenesis in the guinea pig

In the testis, the base of the Sertoli cells is in contact with the basement membrane matrix, in which the laminins constitute the major noncollagenous components. We have previously demonstrated that antibodies against a preparation enriched in basement membranes of seminiferous tubules (STBM) or a noncollagenous fraction of STBM passively transferred induced modifications to the basement membranes and focal sloughing of the seminiferous epithelium in the rat. In the present report, we tested the effect of passive immunization with anti-laminin IgG on the limiting membrane of the seminiferous tubules, spermatogenesis, and maintenance of the blood-testis barrier in the adult guinea pig. Rabbit antibodies to laminin 1 (IgG fraction) were injected in adult male guinea pigs (GP). Nonimmunized GP and GP immunized with normal rabbit serum IgG were used as controls. Measurements of variations in the diameter and lumen of the tubules and in the size of individual components of the tubular limiting membrane showed that the highest percentage of tubules with reduced lumen occurred 30 days after passive immunization with anti-laminin, when the limiting membrane was thickest and lesions to the seminiferous epithelium were most severe. The lesions included thickening of the limiting membrane, infolding in the basal lamina, deposits of immune complexes coincident with sloughing of pachytene spermatocytes and spermatids, and vacuolization of the Sertoli cells. Mononuclear cell infiltration of the tubules was rare. Permeability tracer studies revealed that Sertoli cell tight junctions remained impermeable. Fifty and 80 days after treatment, the basement membrane of the tubules and the progression of the spermatogenesis were normal. Passive immunization with anti-laminin IgG provided a valuable experimental model for the in vivo study of the influence of the basement membrane on the issue of spermatogenesis and the integrity of the seminiferous epithelium.

Autoantibodies to cryptic epitopes elicited by infection with lactate dehydrogenase-elevating virus

Lactate dehydrogenase-elevating virus (LDV) produces a permanent infection in mice with a B-lymphocyte polyclonal activation leading to hypergammaglobulinaemia. Since LDV specifically suppressed antibodies to native epitopes in CBA/Ht, but not BALB/c, mice immunized against a protein antigen, we explored the relationship between such a change in antibody specificity and the expression of autoantibodies under the influence of LDV. Again in CBA/Ht, but not BALB/c, mice we observed another effect of LDV: the sera from infected CBA/Ht mice were found by enzyme-linked immunosorbant assay to contain antibodies to various mouse tissue extracts. Immunoblots revealed a large spectrum of autoantigens that differed markedly between animals. Western-blot competition experiments showed that the protein autoantigens had to be denatured to react with most of the autoantibodies. Despite the presence of these autoantibodies directed to cryptic epitopes, no specific tissue lesions could be ascribed to the autoimmune response elicited by LDV infection, since both mouse strains showed mild inflammatory reactions in liver and kidney.

Endometrial dating and determination of the window of implantation in healthy fertile women

OBJECTIVE

To reassess endometrial morphological criteria of normality identifying the best morphological and molecular "implantation window" indicators in normal women.

DESIGN

Prospective clinical study.

SETTING

Assisted reproductive unit.

PATIENT(S)

Fourteen healthy volunteers.

INTERVENTION(S)

Blood sampling for LH, E(2), and progesterone (P4) determinations. Daily vaginal ultrasounds. Two endometrial biopsies per volunteer, 7 days apart, during luteal phase.

MAIN OUTCOME MEASURE(S)

Endometrial dating, pinopodes formation, immunohistochemical determination of integrins (alphavbeta3, alpha4beta1), leukemia inhibitory factor (LIF), interleukin-1 receptor type I (IL-1R tI), mouse ascites Golgi (MAG), the transmembrane mucin (MUC-1), and P4 receptor expression.

RESULT(S)

In 26 of 28 biopsies observers agreed; in two biopsies there was a discrepancy (difference of 72 hours). With use of LH peak, 24 of 26 samples were in phase, and 2 were 3 days behind. Pinopodes appeared on days 20-21 and persisted through day 28 in small groups or larger areas. beta3 Integrin was highly expressed in luminal and glandular epithelium from day 22 through 28; 48 hours thereafter pinopodes appeared. alpha4 Subunit exhibited luminal epithelium reaction positivity on days 22-23 and glands on days 18-23. LIF and IL-1R tI showed weak, erratic expression. MAG antibodies showed luminal epithelium expression up to day 22 and glands up to day 25. MUC-1 showed positivity during the whole luteal phase. P4 receptors were positive through day 20 and at the end of the luteal phase.

CONCLUSION(S)

The three most cited markers that frame the window of implantation do not correlate in our material. Pinopodes are present from day 20 on; beta3 and alpha4 integrin subunits indicate a window opening on days 22-23.

Effect of testicular macrophage conditioned media from rats with autoimmune orchitis on Leydig cell function

PROBLEM

The aim of this study was to investigate the influence of immune-activated testicular macrophages obtained from rats with autoimmune orchitis (EAO) on Leydig cell steroidogenesis.

METHOD OF STUDY

EAO was induced in rats by active immunization with testis homogenate and adjuvants. Testicular and peritoneal macrophages from rats with EAO were isolated and cultured for 24 hr. Testosterone (T) production by purified Leydig cells incubated in vitro with macrophage-conditioned media (CM) from rats with EAO or control rats was measured.

RESULTS

An increase in T production by Leydig cells incubated with CM from testicular, but not peritoneal, macrophages of rats with EAO was observed. This increase was dose-dependent up to a concentration of 30% CM; proportions higher than 35% exhibited an inhibitory effect.

CONCLUSIONS

Immune-activated testicular macrophages obtained from rats with EAO induced both stimulatory and inhibiting steroidogenic effects on Leydig cells in vitro and not the exclusively inhibitory action that has widely been attributed to activated macrophages. This dual effect probably depends on the ability of these cells to synthesize different molecules that may exert opposite effects.

Serotonin in golden hamster testes: testicular levels, immunolocalization and role during sexual development and photoperiodic regression-recrudescence transition

Serotonin (5-HT) is found in the gonads and accessory reproductive organs of several species. The golden (Syrian) hamster is a seasonal breeder. Exposure of male adult hamsters to short days for 14 weeks results in a severe gonadal regression, while after a photoinhibition period of 22 weeks a spontaneous testicular recrudescence occurs. The aim of this study was to investigate the presence of 5-HT and its major metabolite 5-hydroxyindoleacetic acid (5-HIAA) in the gonads of golden hamsters, its immunolocation and its physiological role in the testis. The influence of age and photoperiod was also analyzed. Hamsters of 23, 36, 46, 60 and 90 days of age were kept in long photoperiod (LP: 14:10 h light/dark), and adult animals were exposed either to LP or to short photoperiod (SP: 6:18 h light/dark) for 14 and 22 weeks. Testicular parenchyma and capsule levels of 5-HT and 5-HIAA increased significantly at ages of 36 and 60-90 days, but decreased markedly during the exposure of adult hamsters to SP for 14 and 22 weeks. Mast cells were found exclusively in the testicular capsule. The testicular number of mast cells increased concomitantly with age, but decreased in adult hamsters exposed to SP. Mast and Leydig cells presented 5-HT-positive immunoreactivity. During sexual maturation as well as during the transfer of adult hamsters from LP to SP, the 5-HIAA/5-HT ratio showed the highest values in active adult animals, indicating that the increase in testicular 5-HT levels in adulthood is accompanied by an augment in 5-HT turnover. In vitro basal and hCG-stimulated testosterone production was significantly inhibited in presence of physiological concentrations of 5-HT. In conclusion, the present studies demonstrate the existence of 5-HT in mast cells and Leydig cells of hamster testes, as well as describe an inhibitory action of this neurotransmitter on gonadal testosterone production. Furthermore, the age-dependent and photoperiodic-related changes detected in testicular 5-HT levels suggest that this neurotransmitter might act as an important local modulator of the action of gonadotropins on steroidogenesis during sexual development and during the photoperiodic regression-recrudescence transition in the golden hamster.

Immunodetection of cell adhesion molecules in rat Sertoli cell cultures

PROBLEM

The presence of cell adhesion molecules (CAMs) in Sertoli cells has not been explored extensively. The expression of CAMs involved in cell-matrix and cell-to-cell interactions in Sertoli cell cultures was examined.

METHOD OF STUDY

Immunohistochemical and Western blot techniques were applied to rat Sertoli cell cultures using specific antibodies to alpha 3, alpha 5, and alpha 6 integrin subunits; NCAM; and cadherins.

RESULTS

Expression of alpha 3 and alpha 6 integrin subunits (mainly laminin receptors) and lack of expression of alpha 5 integrin subunit (fibronectin receptor) was observed in Sertoli cells by immunohistochemistry. These cells also expressed neural CAM (NCAM) and N-cadherin. By Western blot analysis, Sertoli cell extracts reacted with antibodies to alpha 3 integrin subunit revealed a band approximately 130 kDa, whereas no expression of alpha 5 integrin subunit was detected. Cell extracts incubated with antibodies to pan cadherin exhibited a band approximately 120 kDa, whereas bands of 180, 140, and 120 kDa were observed with antibodies to NCAM.

CONCLUSION

New data about the expression of receptors for extracellular matrix proteins (alpha 3 and alpha 6 integrin subunits) as well as cell-to-cell adhesion molecules (NCAM and cadherins) are reported in rat Sertoli cell cultures.

Increased testosterone production in vitro by Leydig cells from rats with severe autoimmune orchitis

We have previously observed (M. O. Suescun et al., 1994, Journal of Andrology, 15, 442-448) that rats with autoimmune orchitis (EAO) exhibit increased testosterone production in vitro by isolated testes. The aim of the present study was to determine whether the increase in testosterone production correlated with an enhanced number of Leydig cells and/or enhanced steroidogenic capacity per Leydig cell. For this purpose, EAO was induced in adult Sprague-Dawley rats by active immunization with testicular homogenate and adjuvants. At 80 days after the primary immunization, 60% of rats presented with severe testicular damage characterized by sloughing of the seminiferous epithelium, seminiferous tubule atrophy and interstitial mononuclear cell infiltration. At 160 days after the first immunization, testicular lesions were more severe. A morphometric study, by light microscopy, showed an increase in the number of Leydig cells in rats with EAO (45% increase at 80 days and 50% at 160 days). By electronmicroscopy, testicular sections of rats with EAO revealed the presence of numerous Leydig cells closely associated with macrophages. Most Leydig cells exhibited ultrastructural features of active steroid secreting cells. The steroidogenic capacity of Percoll-purified Leydig cells from tests of rats with EAO, killed at 80 and 160 days, was evaluated. Leydig cells from rats with EAO exhibited an enhanced steroidogenic response to hCG in vitro at 80 days (38%) and an increase in basal (77%) and post-hCG testosterone production (115%) at 160 days compared to controls. However, these cells were less sensitive to hCG. In conclusion, the results indicate that the enhancement of in-vitro testosterone production observed in rats with EAO is accounted for both by the increased number of Leydig cells and by the increased testosterone production of each Leydig cell.

Immunodetection of cell adhesion molecules and extracellular matrix proteins in rat Leydig cell cultures

Cell adhesion molecules (CAMs) as well as extracellular matrix (ECM) proteins were identified in Leydig cell cultures using immunohistochemical and Western blot analysis. Leydig cells were isolated from 60-day-old rats and cultured for 4 days. For immunofluorescence and immunoperoxidase techniques, Leydig cells were incubated with antisera to ECM proteins (antibodies to laminin, type IV collagen and fibronectin); antisera to integrins (antibodies to beta 1, alpha 3, alpha 5 and alpha 6 integrin subunits) and antisera to cell-to-cell adhesion molecules (antibodies to N-CAM and N-cadherin). Results of the two immunohistochemical techniques were similar. Laminin and type IV collagen were detected in the perinuclear area of Leydig cell cytoplasm and cell processes as bright granular immunofluorescence or as a brown reaction product using the immunoperoxidase technique. Leydig cells expressed alpha 3 and alpha 6 integrin subunits (mainly laminin receptors), while no reaction was detected with antibodies to the alpha 5 integrin subunit (fibronectin receptor). Leydig cells also expressed cell-to-cell adhesion molecules such as N-CAM and N-cadherin. Using Western blot analysis, Leydig cell extracts incubated with antibodies to laminin revealed two bands of around 200 kDa, which is characteristic of laminin 1 light chains. A band with electrophoretic mobility similar to that of the alpha 2 (IV) collagen chain from EHS sarcoma and a band of around 230 kDa similar to fibronectin were also detected in Leydig cell extracts using specific antisera. Leydig cells incubated with antibodies to the alpha 3 integrin subunit revealed two bands below 120 kDa. Finally, Western blot results showed that Leydig cells expressed N-CAM as two faint bands of around 140 kDa and N-cadherin as a 120 kDa band. The present data suggest that Leydig cells in culture are able to synthesize ECM proteins and express ECM receptors (integrins), as well as cell-to-cell adhesion molecules such as N-CAM and N-cadherin.

Alterations in cardiac muscarinic acetylcholine receptors in mice with autoimmune myocarditis and association with circulating muscarinic receptor-related autoantibodies

Hearts from mice hyperimmunized with cardiac tissue were studied to evaluate the expression and biological activity of muscarinic cholinergic receptors and immunoglobulin G deposits along the immunization period. Mice were sacrificed at 10 day intervals from the first injection up to day 100. Simultaneously, the activity of autoantibodies against muscarinic receptors on normal hearts was also examined in sera. Hearts with autoimmune myocarditis showed a muscarinic receptor-related dysfunction, with an impaired response to exogenous muscarinic agonists and a significant reduction in muscarinic binding sites, both effects being maximum at 40-50 days post-immunization. In addition, serum or immunoglobulin G from mice with myocarditis were able to interact with muscarinic acetylcholine receptors displaying a partial agonist effect. Autoimmune sera and immunoglobulin G reduced heart contractility while inhibited 3H-QNB binding to cardiac acetylcholine receptors in a concentration dependent manner showing the highest effects at days 40-50 and decreased progressively thereafter. The development of muscarinic receptor-related cardiac dysfunction may be associated with the presence of circulating antibodies having muscarinic receptor activity. These studies are of relevance to clinical conditions such as Chagas' disease, where immunological processes involving the cholinergic system are considered to cause cardiomyopathy.

Alterations of testicular function after induced autoimmune orchitis in rats

The endocrinological profile of animals with experimental autoimmune orchitis (EAO) has not been sufficiently explored. With this purpose orchitis was induced in adult rats by active immunization with testicular homogenate (TH) and adjuvants. Animals were sacrificed 50 or 80 days after the first immunization. Forty-three percent of rats immunized with TH developed orchitis. Different degrees of cell sloughing and atrophy of the seminiferous tubules and numerous macrophages and lymphocytes in close association with Leydig cells were seen. A significant increase in the number of Leydig cells was observed in rats with orchitis killed at 50 and 80 days. An enhanced number of interstitial non-Leydig cells was also detected in rats with testicular damage killed at 80 days. Levels of serum follicle-stimulating hormone (FSH) were two- to threefold higher in rats with EAO compared to concentrations detected in other groups. Moreover, rats with orchitis had significantly increased testicular testosterone. Serum luteinizing hormone (LH) did not change in animals of any group. In vitro studies showed an increase in the basal and human chorionic gonadotropin (hCG)-stimulated testosterone production in rats with EAO. The increase in testicular steroidogenesis without a concomitant enhancement in serum LH levels detected in rats with autoimmune orchitis suggests the existence of local control mechanisms.

Participation of cytoskeleton in the effect of antilaminin IgG on cardiac cholinoceptors

1. We have previously demonstrated a molecular relationship between laminin and cardiac cholinoceptors. 2. We have now explored the participation of cytoskeletal proteins in the interaction between an antilaminin IgG with cardiac cholinoceptors. 3. Antilaminin IgG, whilst it specifically reacts with laminin molecules was able to induce cardiac cholinoceptor activation; acting like an agonist, decreasing cyclic AMP concentrations, reducing heart contractility and increasing phosphoinositide turnover. 4. Antilaminin IgG also interfered with the binding of a radiolabelled muscarinic antagonist, [3H]-quinuclidinyl benzilate. Colchicine and cytochalasin B, drugs that are able to prevent microfilament and microtubule polimerization, impaired the binding of antilaminin IgG to muscarinic cholinoceptors. 5. Cytochalasin B but not colchicine modified the muscarinic cholinoceptor effects mediated by regulatory G proteins (cyclic AMP and contractility) induced by antilaminin IgG. 6. It was demonstrated, by immunofluorescence, that none of these disrupting drugs altered the specific recognition of the antibody by its antigen. 7. These data indirectly suggest the participation of the cytoskeleton in the laminin and cholinergic receptor association.

Phenotypic characterization of lymphocytic cell infiltrates into the testes of rats undergoing autoimmune orchitis

Experimental autoimmune orchitis (EAO) was induced in adult Wistar rats by active immunization with a testicular homogenate (TH) and adjuvants. Fifty per cent of the immunized rats developed EAO. Testicular damage became evident at 50 days after the primary immunization and increased in severity at 80 days. Phenotypic characterization of T-cell subsets (CD4+ and CD8+) and Ia+ cells was performed on cryostat sections of testis obtained from normal rats, rats immunized with adjuvant (control group) and rats immunized with TH and adjuvants (experimental group) at 50 and 80 days. Labelled cells were only detected in the interstitial area; no labelled cells were observed inside the seminiferous tubules with any of the monoclonal antibodies used (W3/25, OX-8, OX-6). A significant increase in the numbers of CD4+ and CD8+, as well as of Ia+ cells, were observed in the testis of rats with severe EAO at 80 days after the first immunization. Rats of the same experimental group without testicular damage showed no major differences compared to rats from the control group, with the exception of a lower number of CD8+ cells. Variations in the lymphocyte subsets in lymph nodes draining the site of immunization showed the opposite pattern to that observed in the testis. In conclusion, these data suggest the traffic of specifically sensitized lymphocytes from lymph nodes to the testis and an active role of CD4+, CD8+ and Ia+ cells in the pathogenesis of EAO in the rat.

Antilaminin IgG triggers the murine atria phosphoinositide hydrolysis through muscarinic receptor stimulation

Induction of polyphosphoinositide hydrolysis in cardiac tissue by specific recognition of laminin by antilaminin IgG was assayed. BALB/c mice atria were labelled with the myo-[3H]-inositol precursor and inositol phosphate production was measured in the presence and absence of antilaminin and normal IgG. Antilaminin IgG but not normal IgG specifically increased phosphoinositide (PI) turnover. This increment was blocked by the muscarinic cholinergic antagonist atropine and mimicked by the cholinergic agonist carbachol. The phospholipase C inhibitor diphenylcarbamate (NCDC) also antagonized the stimulatory action of antilaminin IgG on PI turnover. By using an immunofluorescence technique, antilaminin IgG reacted with myocardial cell basement membranes. This antibody fixation was not blocked by atropine. These data suggest that antilaminin IgG specifically recognized myocardial laminin molecules and activated PI turnover through cholinergic stimulation. Even though laminin and cholinergic receptors are different, they probably share common signal transduction systems.

The California Maternal Serum alpha-Fetoprotein Screening Program: the role of ultrasonography in the detection of spina bifida

Between January 1988 and June 1990, 161 cases of open spina bifida were identified by the California Maternal Serum alpha-Fetoprotein Screening Program. Eight percent of these cases were not diagnosed by an initial ultrasonographic evaluation. Three defects were not recognized until birth. Ultrasonography is inadequate to identify all cases of open spina bifida.

Testicular lesions and lymphocyte subpopulations in rats immunized with a soluble fraction of testicular homogenate

A soluble fraction obtained from a testicular homogenate by precipitation with ammonium sulphate (ASPM) was emulsified with Freund's complete adjuvant (CFA) and injected into Wistar rats. At 50 days after the first immunization (total of three injections) the animals had developed moderate and multifocal testicular damage, characterized mainly by sloughing of the seminiferous epithelium. A delayed-type hypersensitivity response and circulating antibodies to ASPM were detected at different times with maximum levels at 50 days. The addition of Bordetella pertussis to the immunization did not increase the severity of the lesion but augmented the cellular and humoral immune response to ASPM. The phenotypic characterization of cells present in the lymph nodes draining from the site of immunization in animals injected with CFA alone (control group) revealed an increase in CD8+ T-cells and a low CD4/CD8 ratio. Conversely, rats immunized with CFA plus ASPM (experimental group) exhibited testicular damage and showed a significant decrease in CD8+ cells with a normal CD4/CD8 ratio. In conclusion, rats immunized with a testicular antigen developed focal aspermatogenic lesions and a concomitant specific immune response as well as lymph-node cell variations focused apparently on the CD8+ T-cell subpopulation.

Lymphocyte subsets in the lymph nodes of rats with autoimmune orchitis

We determined temporal variations of cell subpopulations in the immunization draining lymph nodes during the development of an experimental autoimmune orchitis (EAO) induced in Wistar rats. A phenotypic characterization of T cells and their subsets (CD4+ and CD8+), B, and Ia+ cells was performed by immunofluorescent technique. At the end of the immunization period (30 days), rats injected with testicular homogenate plus adjuvants presented a considerable increase in absolute cell number but normal lymphocyte subset percentages. Testicular damage became evident at 50 days after the first immunization and increased its severity at 80 days: animals that developed EAO presented a lower number of CD8+ cells as compared with undamaged rats. This latter group showed a low CD4/CD8 ratio due to the high proportion of CD8+ cells, which could probably have a suppressor function. At 80 days massive testicular infiltration and decreased absolute cell number in lymph nodes suggest the possible migration of specific lymphocytes to the target organ.

Antilaminin IgG binds and interacts with cardiac cholinergic receptors

Antilaminin IgG bound to cholinergic muscarinic receptors of normal mice heart and simulated the biological effect of a cholinergic agonist. Antilaminin IgG interfered with the binding of the radiolabelled muscarinic antagonist, (-)-[3H]quinuclidinyl benzilate, in a noncompetitive fashion. The interaction of antilaminin IgG with the muscarinic cholinergic receptor increased production of cGMP and decreased production of cAMP. Antilaminin IgG also decreased the contractile tension of mouse atria. Both the mechanical and enzymatic effect of antilaminin IgG required the activation of the muscarinic cholinergic system because they were blunted by atropine and mimicked by acetylcholine.

Feline parvovirus propagates in cat bone marrow cultures and inhibits hematopoietic colony formation in vitro

Feline parvovirus (FPV) causes leukopenia in naturally infected cats. We investigated the mechanism of hematopoietic depression by this virus in feline bone marrow cultured in vitro. In suspension cultures we demonstrated FPV propagation and replication using DNA molecular hybridization. Viral RNA and DNA were observed by in situ hybridization in about 10% of marrow cells at day 3. Granulocytes and their precursors were virtually absent from infected cultures after six days. Infected cells showed viral capsid protein predominantly in nuclei by immunofluorescence. In clonal assays, FPV most efficiently inhibited hematopoietic colony formation by myeloid progenitor cells (CFU-GM), but erythroid colony formation (BFU-E and CFU-E-derived) was also depressed in the presence of virus. Inhibition of colony formation could be abrogated by physical inactivation of the virus or preincubation with specific neutralizing antibodies. Recombinant human colony stimulating factors GM-CSF and G-CSF supported feline myelopoiesis in progenitor assays, and FPV completely inhibited factor dependent colony formation.

Negative inotropic activity of antilaminin IgG: participation of cholinergic mechanisms

1. Antilaminin IgG decreased the dF/dt of mouse isolated atria and inhibited the mechanical effect of acetylcholine in a non-competitive fashion. 2. Inhibitors of nicotinic and muscarinic cholinoceptors impaired the negative inotropic action of antilaminin IgG in mouse isolated atria. Hemicholinium and tetrodotoxin also reduced the response while the antihistamine, pyrilamine was without effect. 3. These results suggest that antilaminin IgG modulates cholinergic function in mouse isolated atria. Possible mechanisms are discussed.

Sequential study of the histopathology and cellular and humoral immune response during the development of an autoimmune orchitis in Wistar rats

Wistar rats immunized with an homologous testicular homogenate (TH) and complete Freund's adjuvant, followed by i.v. injection of Bordetella pertussis, developed an autoimmune orchitis (EAO). Animals were studied at 7, 16, 30, 50, and 80 days (d) after the first immunization. An important lesion of the testis only appeared at 50 d, increasing in severity and incidence (77%) at 80 d. Lesions were characterized by a prevalent aspermatogenesis with tubular atrophy and mild interstitial mononuclear infiltrates. Delayed-type hypersensitivity response (DTH) against TH was detected early at 7 d and, except for 16 d, it increased with time, reaching a maximum at 80 d. A good temporal relationship between DTH and histopathology was found. Circulating antibodies to TH, detected by ELISA, were only present in 64% of the animals with testis lesion, while no deposits of IgG or C3 in the seminiferous tubules were seen. We describe a sequence of immunological events, concomitant with pathological changes of the testis, during the development of a severe EAO in Wistar rats.

California's experience with low MS-AFP results

The California AFP Screening Program was developed to offer pregnant women the opportunity to have their pregnancies screened for open neural tube defects (NTD). Because it is unwise to withhold potentially important clinical information about low MS-AFP results from the screened women and their physicians, follow-up diagnostic evaluations and counseling were offered to women with low MS-AFP results in addition to those with high results or positive family histories of NTD. Between April 7, 1986 and September 30, 1987, over 275,000 women voluntarily participated in the screening program. During the first year of the program 3,939 women were seen for follow-up evaluations due to low MS-AFP results. These evaluations occurred at state-approved AFP follow-up centers where ultrasonographic dating led to reinterpretation of 35% of the results. Of the remaining 2,552 (65%), 1,940 women (76%) had an amniocentesis. Sixteen Down syndrome fetuses were detected for a yield of 1/121 amniocenteses. Additional chromosome abnormalities included trisomies 18 and 13, Ullrich-Turner syndrome, (45,X), Klinefelter syndrome (47,XXY) and triploidy. The total yield of significant chromosome abnormalities was 1/78 amniocenteses.

Testis lesions and cellular and humoral immune responses induced in rats by immunization with laminin

Sixty-six percent of rats immunized with laminin isolated from a mouse Engelbreth-Holm-Swarm (EHS) sarcoma developed moderate lesions in the testis characterized by multiple foci of seminiferous tubules with different degrees of sloughing of the germinal epithelium or atrophy intermingled with normal histological areas. Interstitial mononuclear cell infiltrates were seen in the epididymis. By electron microscopy, pathological changes in the basement membranes of the seminiferous tubules, such as splitting and focal thickenings of knob-like projections toward the epithelium, were observed. Moreover, Sertoli cell cytoplasm showed dilated smooth endoplasmic reticulum and large vacuoles. By electron microscopy with the immunoperoxidase technique, staining for in vivo-bound rat IgG was detected along the walls of the seminiferous tubules as a bright linear immunofluorescence and as a dense reaction product on the basal lamina. High titers of circulating antilaminin antibodies were detected by ELISA in all the rats immunized with laminin. As revealed by the skin test, a delayed type hypersensitivity reaction to laminin was observed in these rats.

Induction of multifocal lesions of the testis by passive transfer of immune cells

Spleen cells obtained from Wistar rats bearing a multifocal damage of the testis that had been induced by an antiserum against a non-collagenous fraction of basement membranes, were able to transfer similar testicular lesions into normal recipients. Damage was characterized by multiple foci of seminiferous tubules with different degrees of cell sloughing and a mild interstitial mononuclear cell infiltrate. The incidence of testicular damage in the transferred recipients was 83%, while in the control group of rats transferred with spleen cells from donors that had been injected with normal rabbit serum only 4% of the animals presented mild lesions. In order to determine which lymphocyte subpopulations were effective in transferring the disease, rat spleen cells were treated with murine monoclonal antibodies W3/25 and OX8 or with a rabbit anti-rat IgG serum and complement, before the transfer. A multifocal damage of the testes, indistinguishable from that obtained with the untreated spleen cells was transferred in 50% and 25% of the rats injected with spleen cells depleted in B or in T lymphocytes, respectively. The most severe lesions were observed in the rats transferred with cell populations depleted in B cells.

Multifocal damage of the testis induced in rats by passive transfer of antibodies prepared against non-collagenous fraction of basement membrane

Multifocal damage of the testis was induced in 70% of the rats injected with an antiserum against a non-collagenous fraction (D-STBM) obtained from a preparation enriched in basement membranes of seminiferous tubules. The damaged areas were characterized by perivascular and peritubular cell infiltrates, changes in the walls of small vessels and seminiferous tubules, and sloughing of the germinal epithelium. By electron microscopy, the most frequent changes observed in basement membrane of the seminiferous tubules were folding, focal thickening, and delamination. By immunofluorescence, discontinuous linear deposits of rabbit IgG were observed along the walls of the seminiferous tubules. In the same localization, faint immunofluorescence showing the presence of rat IgG was also detected. The same pattern was obtained when rabbit and rat IgG eluted from the testes of these rats were layered on sections of normal rat testis. Moreover, by immunoelectron microscopy, discontinuous deposits of rabbit IgG were detected along the basement membranes of the seminiferous tubules. Neither C3 deposits nor changes in the serum CH 50 were observed. By leucocyte migration inhibition reaction (LMIR) a cellular immune response to basement membrane antigens was detected. In the control group, 12% of the rats injected with normal rabbit serum presented mild interstitial cell infiltrates and occasional sloughing of the germinal epithelium. Neither deposits of rat IgG or rabbit IgG nor a cellular immune response were observed.

Biosynthesis of basement membrane by parietal yolk sac cells

The biosynthesis of basement membrane (Reichert's membrane) by parietal yolk sac cells of the mouse embryo was studied using immunohistochemistry and autoradiography with the electron microscope. Fab' fragments of characterized antisera to either a mixture of type IV collagen and laminin, or to type IV collagen alone, were conjugated to horseradish peroxidase for the immunohistochemical study; radiolabeled proline, leucine, and glucosamine were utilized either in vivo or in isolated yolk sac membranes in vitro for autoradiography. Whereas neither of the two antisera employed localized in either the Golgi apparatus or in the cytosol, both localized in the rough endoplasmic reticulum (RER) and in the extracellular basement membrane. Furthermore, no evidence of passage of isotopically labeled precursors of basement membrane from the RER to the Golgi apparatus was observed. Consequently, it is concluded that the basement membrane precursors are synthesized in the RER of parietal yolk sac cells and neither traverse the Golgi apparatus nor diffuse across the cytosol of the cell in the process of secretion. By elimination, secretion must be via direct communications between RER and plasma membrane or via small vesicles observed in the cytosol between RER and plasma membrane. These data are not in accord with the concept of the universality of the Golgi apparatus in the biosynthesis of glycoprotein. Parietal yolk sac cells do not use the Golgi apparatus in the biosynthesis of basement membrane, but do use the Golgi apparatus for the biosynthesis of other proteins.

Antigens of the basement membranes of the seminiferous tubules induce autoimmunity in Wistar rats

A preparation enriched in basement membranes from seminiferous tubules was isolated from rat testes (STBM) and injected with complete Freund's adjuvant into Wistar rats. In 60% of animals a mild multifocal orchitis was observed. In damaged areas, perivascular and peritubular mononuclear cell infiltrates and different degrees of cell sloughing of some seminiferous tubules were observed. Electron microscopy revealed focal thickenings and delamination of the basement membrane of the seminiferous tubules as well as vacuolization of Sertoli cell cytoplasm. Using immunofluorescence discontinuous linear deposits of IgG were detected along the seminiferous tubular wall. Moreover, the same pattern of immunofluorescence was observed when the IgG eluted from the testes of the immunized rats was layered on sections of normal rat testis. Circulating antibodies to STBM were detected using passive haemagglutination in approximately 45% of the immunized rats, with titers ranging from 1:20 to 1:80. Leukocyte migration was inhibited when the spleen cells of the immunized rats were incubated with antigens from the basement membrane of seminiferous tubules, whilst a negative reaction was obtained when the soluble fraction of testis homogenate was used.

Isolation and immunological reactivity of soluble fractions from rat seminiferous tubule basement membrane

A preparation rich in basement membranes isolated from rat testes (STBM) was exposed to pepsin, collagenase, trypsin, and pronase to obtain soluble fractions. The immunological reactivity of these fractions was studied by gel immunodiffusion or by passive hemagglutination tests against an anti-STBM serum. All fractions reacted with the antiserum, but the highest titer was detected when the antiserum was reacted with a fraction that contained only traces of hydroxyproline (fraction 1), whereas low titers were obtained with collagen or collagen fragments isolated from STBM. Antibodies in the anti-STBM serum were mainly directed to the glycoproteins of STBM not related to collagen. Fraction 1, obtained by subsequent collagenase and trypsin digestion of STBM and purification by Sephadex G-200, was a high molecular weight glycoprotein that was free of half-cystine and methionine, had only traces of hydroxyproline, and contained 7.2% neutral sugars, 0.26% sialic acid, and 8.7 residues of glucosamine per 1000 residues of amino acids.

Experimental orchitis induced in rats by passive transfer of an antiserum to seminiferous tubule basement membrane

A multifocal damage of the testis was obtained when rats were injected intravenously or under the tunica albuginea of the testis with a rabbit antiseminiferous tubule basement membrane serum. The damage was characterized by foci of perivascular and peritubular infiltrates of mononuclear round cells, infolding, thickening, and rupture of the seminiferous tubular wall and different degrees of injury of the germinal epithelium such as, cell disorganization, cell sloughing, and atrophy. Delamination and thickening of seminiferous tubule basement membrane and vacuolization of the Sertoli cell cytoplasm was often observed by electron microscopy. A linear deposit of rabbit gamma-globulin was detected by immunohistochemical techniques along the basement membranes of the seminiferous tubules and vessels. Testicular damage was not detected in rats injected with normal rabbit serum, used as control. In the kidneys of rats injected intravenously with the immune serum, a deposit of rabbit gamma-globulin was detected along glomerular basement membrane. Focal areas of mononuclear cell infiltrates, hypercellularity of glomeruli and thickening of glomerular capillary walls and Bowman's capsule were also observed.

Partial chemical and immunological characterization of pepsin-solubilized collagen from the tunica albuginea of rat testis

A pepsin-solubilized collagen was isolated from the tunica albuginea of rat testis. Intrinsic viscosity, amino acid and carbohydrate composition were similar to data reported for other soluble collagens. An antiserlm to the pepsin-solubilized collagen was obtained and by indirect immunofluorescence an antigen-antibody reaction was observed in the collagen fibers of the tunica albuginea and in the intertubular collagen fibers of rat testis. By serological and immunofluorescence techniques, cross-reactions with other collagens indicates a lack of organ specificity. A strong cross-reaction between this antiserum and basement membranes from different organs of the rat was also found.

Ultrastructural localization of a soluble collagen antigen

Soluble collagen antigen was localized at the ultrastructural level using an enzyme-labeled antibody technique. Specific antiserum against neutral salt-soluble collagen was conjugated with horseradish peroxidase. Tissue culture of fibroblasts, sections of chick embryo connective tissue and skin and tendon of newborn and adult chickens were incubated with the conjugated antiserum and processed for light and electron microscopy. Light microscopic observations showed a localization of the collagen antigen in the cytoplasm of fibroblasts and in the extracellular collagen fibers. Ultrastructurally, the antigen was found on the ribosomes, on the membranes of the rough endoplasmic reticulum, in the intracisternal material of fibroblasts and extracellularly in the collagen fibrils. The collagen fibrils of chick embryo cartilage were intensely stained while the matrix itself remained unstained. Controls performed with absorbed antiserum, conjugated normal rabbit serum or different antigens failed to react with the tissues.